Blowing Up Balloons With CO2

Chemistry tuition classes in Miracle Learning Centre is very beneficial. If you do not understand chemistry, you must definitely try the chemistry tuition class at Miracle Learning Centre. Let us learn about the preparation of Blowing Up Balloons With CO2.

What you'll need:

Balloon About 40 ml of water (a cup is about 250 ml so you don't need much) Soft drink bottle Drinking straw Juice from a lemon 1 teaspoon of baking soda

Instructions:

Before you begin, make sure that you stretch out the balloon to make it as easy as possible to inflate. Pour the 40 ml of water into the soft drink bottle. Add the teaspoon of baking soda and stir it around with the straw until it has dissolved. Pour the lemon juice in and quickly put the stretched balloon over the mouth of the bottle.

What's happening?

If all goes well then your balloon should inflate! Adding the lemon juice to the baking soda creates a chemical reaction. The baking soda is a base, while the lemon juice is an acid, when the two combine they create carbon dioxide (CO2). The gas rises up and escapes through the soft drink bottle, it doesn't however escape the balloon, pushing it outwards and blowing it up. If you don't have any lemons then you can substitute the lemon juice for vinegar.

Make Your Own Quick Sand

Science Tuition classes in Miracle Learning Centre is very beneficial. If you do not understand science, you must definitely try the chemistry tuition class at Miracle Learning Centre. Let us learn about the preparation of Quick Sand in this chemistry tuition lesson. Quick sand is a fascinating substance, make some of your own and experiment on a safe scale. Amaze your friends by demonstrating how it works.

What you'll need:

1 cup of maize cornflour Half a cup of water A large plastic container A spoon

Instructions:

This one is simple, just mix the cornflour and water thoroughly in the container to make your own instant quick sand. When showing other people how it works, stir slowly and drip the quick sand to show it is a liquid. Stirring it quickly will make it hard and allow you to punch or poke it quickly (this works better if you do it fast rather than hard). Remember that quick sand is messy, try to play with it outside and don’t forget to stir just before you use it. Always stir instant quicksand just before you use it!

What's happening?

If you add just the right amount of water to cornflour it becomes very thick when you stir it quickly. This happens because the cornflour grains are mixed up and can’t slide over each other due to the lack of water between them. Stirring slowly allows more water between the cornflour grains, letting them slide over each other much easier. Poking it quickly has the same effect, making the substance very hard. If you poke it slowly it doesn’t mix up the mixture in the same way, leaving it runny. It works in much the same way as real quick sand.

Make Glowing Water

Chemistry tuition classes in Miracle Learning Centre is very beneficial. If you do not understand chemistry, you must definitely try the chemistry tuition class at Miracle Learning Centre. Let us learn about the glowing water in this chemistry tuition lesson.

Tonic water doesn't look very strange under normal light but what happens when you look at it under a black light? Does the dye from a highlighter pen do the same thing? Find out what happens and why it happens with this cool experiment that you can do at home.
What you'll need: A black light (you can find them at places like Walmart and hardware stores, as well as online stores like Amazon). Tonic water or a highlighter pen. A dark room to do the experiment.

Instructions: If you are using a highlighter pen carefully break it open, remove the felt and soak it in a small amount of water for a few minutes. Find a dark room. Turn on the black light near your water, how does it look?

What's happening? Simple explanation: The ultra violet (UV) light coming from your black light lamp excites things called phosphors. Tonic water and the dye from highlighter pens contain phosphors that turn UV light (light we can’t see) into visible light (light we can see). That’s why your water glows in the dark when you shine a black light on it. Black lights are used in forensic science, artistic performances, photography, authentication of banknotes and antiques, and in many other areas. Detailed explanation: Black light (also known as UV or ultra violet light) is a part of the electromagnetic spectrum. The electromagnetic spectrum also includes infrared, X-rays, visible light (what the human eye can see) and other types of electromagnetic radiation. A black light lamp such as the one you used emits a UV light that can illuminate objects and materials that contain phosphors. Phosphors are special substances that emit light (luminescence) when excited by radiation. Your water glowed under the black light because it contained phosphors. If you used a highlighter pen then the UV light reacted with phosphors in the dye. If you used tonic water then the UV light reacted with phosphors in a chemical used in tonic water called quinine. There are different types of luminescence, they include fluorescence (used in this experiment, it glows only when the black light is on), phosphorescence (similar to fluorescence but with a glow that can last even after the black light is turned off), chemiluminescence (used to create glow sticks), bioluminescence (from living organisms) and many others.

Melting Chocolate

Science tuition classes in Miracle Learning Centre is very useful. If you do not understand science, you must definitely attend the science tuition class at Miracle Learning Centre. Let us learn about melting chocolate in this science tuition lesson.

Enjoy this simple melting chocolate experiment for kids. You've no doubt experienced chocolate melting on a hot day, so let's do some experiments to recreate these conditions as well as a few others before comparing results and coming to some conclusions.

At what temperature does chocolate go from a solid to a liquid? Is it different for white and dark chocolate? Give this fun science experiment a try and find out!

What you'll need: Small chocolate pieces of the same size (chocolate bar squares or chocolate chips are a good idea) Paper plates Pen and paper to record your results

Instructions: Put one piece of chocolate on a paper plate and put it outside in the shade. Record how long it took for the chocolate to melt or if it wasn't hot enough to melt then record how soft it was after 10 minutes. Repeat the process with a piece of chocolate on a plate that you put outside in the sun. Record your results in the same way. Find more interesting locations to test how long it takes for the chocolate pieces to melt. You could try your school bag, hot water or even your own mouth. Compare your results, in what conditions did the chocolate melt? You might also like to record the temperatures of the locations you used using a thermometer so you can think about what temperature chocolate melts at.

What's happening? At a certain temperature your chocolate pieces undergo a physical change, from a solid to a liquid (or somewhere in between). On a hot day, sunlight is usually enough to melt chocolate, something you might have unfortunately already experienced. You can also reverse the process by putting the melted chocolate into a fridge or freezer where it will go from a liquid back to a solid. The chocolate probably melted quite fast if you tried putting a piece in your mouth, what does this tell you about the temperature of your body? For further testing and experiments you could compare white choclate and dark chocolate, do they melt at the same temperature? How about putting a sheet of aluminium foil between a paper plate and a piece of chocolate in the sun, what happens then?

Bite Size Physics, Popping the Cork

Physics tuition classes in Miracle Learning Centre are very beneficial. If you do not understand physics, you must definitely try the physics tuition class at Miracle Learning Centre. Let us learn about the reaction of acids and a metal carbonate in this physics tuition lesson.

This experiment will pop a cork out of a wine bottle and make it go 50 to 60 feet! This is best done outdoors. If you do it with few ingredients there’s very little mess. Be careful with this. The cork comes out with a good amount of force, don’t point it at anyone or anything. Don’t point it at yourself.

Ingredients Wine bottle Cork (be careful that the corkscrew doesn’t go all the way through it) Baking Soda Vinegar Paper towel 1. Put about one inch of vinegar into the bottle. 2. Shove a wad of paper towel as far into the neck of the bottle as you can. Make sure the wad is not too tight. It needs to stick into the bottle but not too tight. 3. Pour baking soda into the neck of the bottle. Fill the bottle from the wad of paper all the way to the top of the bottle. 4. Now put the cork into the bottle fairly tightly. 5. Now tap the bottle hard on the floor or table to force the wad of paper and the baking soda into the bottle. 6. Give the bottle a bit of a shake. 7. Set it down and watch. 8. If it doesn’t blast in 30 seconds to 1 minute then give the cork a little nudge. Be careful to not get in front of the cork.

Magic ink

Chemistry tuition classes in Miracle Learning Centre are very useful. If you do not understand chemistry, you must definitely attend the chemistry tuition class at Miracle Learning Centre. Let us learn about magic link in this chemistry tuition lesson.
Help your kids discover the magic of the amazing science experiment and kids activity that creates magic ink. Watch their eyes widen in wonder as they uncover the secrets behind the amazing possibilities of science!
Number of players: 1+
What you need: • lemon • water • small plate • toothpick • white paper • lamp

Activity:

Squeeze the lemon juice into a small plate with a few drops of water and mix with a spoon. Dip the toothpick into the lemon juice mix and write a message on the white sheet of paper. When it dries the writing will be invisible. Heat the paper by holding it over a lamp with the writing side down. The invisible ink writing will slowly turn brown and appear on the page! http://www.miraclelearningcentre.com

What Is Physics?

Physics mainly deals with motion, energy, force and matter. It is one of the fundamental branches of Science. Physics is based on a number of central theories from which everything else develops.

How to Study Physics?

From my point of view Physics is very much truly beautiful subject. It is the most fascinating and awe-inspiring subject in the world. But majority of physics students think that physics is one of the difficult subjects in the world. Due to lack of concentration in class most of the students are unable to solve the mathematical integration of Physics. So I want to share some few tips for effective participation in Physics Tuition Class.

1) Follow the classes very carefully.

2) Read the introduction and the summary of the relevant chapter and look at the section headings and subheadings. Try to solve the mathematical problem for every chapter.

3) Make notes for new terminology, general laws, and new units of measure.

4) Before the beginning of class please study the whole chapter in advance so that you will follow the new terminology or new thoughts which will be discussed in class.

5) Do more practice in your home and feel free to ask to your teacher.

6) Ensure you can answer all points mentioned in the syllabus to the level required by the verb used.

7) Always follow your book and make a study copy.

Why Private Tuition?

If your aim is to develop your knowledge and aptitude in a particular field, classroom training is not proper solution. In a classroom one teacher may be faced with around thirty pupils, each with different abilities, different rates of learning, and individual strengths and weaknesses. So it is very much unfortunate to handle all these students in a good manner. Compared to the conflicts of the classroom, private tuition is very much effective for mediocre students, which are unable to concentrate their minds while being in a class.

Why Miracle Learning Centre?

Miracle Learning Centre Pvt Ltd specializes in Science and Mathematics. Other than Chemistry, Physics is another Science subject that Miracle is strong in. Physics concepts are not easy to explain and not all teachers can explain well. Physics concepts are not easy to explain and not all teachers can explain well. All our Physics teachers are NIE trained, ex-school teachers who explain concepts very clearly and are able to give examples to elaborate the Physics concept. Physics teachers need to be very well versed in the subject to be able to explain the subtle differences in the topic. They will also highlight what to take note of and to be precise in your answers and calculations.

Learn About Our Physics Teachers:

Profile of Mr Wong – Mr Wong obtained his PGDE(merit) from NIE and was previously with Fairfield Methodist Secondary School. With 10 years of school teaching experience, he believes that the teacher’s pedagogical style is crucial in helping students achieve academic success. Therefore, the instructional scaffolding provided must be intentional and purposeful. A experienced teacher who explains concepts very well.

Profile of Ms Ong – Ms Ong is an ex-secondary school science teacher for 5 years, and work on improving the academic results of students and nurturing an environment that promotes creativity and innovation within individuals. She is experienced in providing class tuition for lower Sec Science/Physics/Chemistry/Mathematics for more than 10 yrs. Miss Ong has a Bachelor of Applied Science with Merits (Materials Engineering) from Nanyang Technological University of Singapore(NTU) and a Diploma in Education (Post-Graduate) Secondary from National Institute of Education(NIE).

Profile of Mr Lim – Mr Lim is an ex-secondary school teacher with more than 12 years of teaching experience. He specialises in Chemistry and Physics (secondary levels). A very patience teacher whom guide students through detailed step-by-step approach to problem solving as well as engaging in discussion/dialogue format of presentation in class room experience.

Miracle Learning Centre Chemistry Tuition Question on Qualitative Analysis . (O Level Chemistry Tuition/ IP Chemistry Tuition)

1. What gas is formed when aluminium powder is heated with alkaline aqueous sodium nitrate? A. oxygen B. nitrogen C. ammonia D. nitrogen dioxide

2. A solid is insoluble in water but dissolves in aqueous acid and in aqueous alkali without evolution of a gas in either case. What could the solid be? A. copper(II) carbonate B. copper(II) hydroxide C. zinc carbonate D. zinc hydroxide

3. Which one of the following solutions, when mixed, would give a visible change? A. Kl(aq) and NaOH(aq) B. CuSO4(aq) and MgCl2(aq) C. FeCl3(aq) and NH3(aq) D. NaCl(aq) and KOH(aq) Miracle Learning Centre Answer to Chemistry Tuition Question on Qualitative Analysis. (O Level Chemistry Tuition/ IP Chemistry Tuition) 1)C 2)D 3)C Learn from our Chemistry Tuition Questions and Answers. Miracle Learning Centre Call 6463 8756 or sms 8128 8342/9839 9908. (Specialist in Science and Maths) for Primary, Secondary and JC levels. Miracle Learning Centre specialises in Chemistry tuition, Physics tuition, Maths tuition and Science tuition Classes.

Miracle Learning Centre Chemistry Tuition Question on Periodic Table . (O Level Chemistry Tuition/ IP Chemistry Tuition)

Use the information in the table to answer the questions below. (You may use a letter once, more than once or not at all.)

(a) Which element could be hydrogen ? Give a reason for your choice. …………………………………………………………………………………………. …………………………………………………………………………………………. …………………………………………………………………………………………. (b) Which two elements are in the same Group of the Periodic Table ? Give a reason for your choice. …………………………………………………………………………………………. …………………………………………………………………………………………. (c) Using columns 3 and 4, calculate the mass of 1 mole of M and identify M ……………………………………………………………………………..……………. …………………………………………………………………………………………. …………………………………………………………………………………… (d) Give two observations you might make when element R is added to a dilute hydrochloric acid. ……………………………………………………………………………..……………. …………………………………………………………………………………………. …………………………………………………………………………………… Miracle Learning Centre Answer to Chemistry Tuition Question on Periodic Table . (O Level Chemistry Tuition/ IP Chemistry Tuition) 1. a. A. 24 dm3 of A weighs 24 x 0.08 g i.e. approx = 2 g b. G and J They have the same valency, one, towards oxygen and form oxides of similar formula c. Mass of one mole of M = 3 x 15 = 45 g Scandium d. There is an effervescence forming a colourless and odourless gas A pale green solution formed. Element R becomes smaller in size Learn from our Chemistry Tuition Questions and Answers. Miracle Learning Centre Call 6463 8756 or sms 8128 8342/9839 9908. (Specialist in Science and Maths) for Primary, Secondary and JC levels. Miracle Learning Centre specialises in Chemistry tuition, Physics tuition, Maths tuition and Science tuition Classes.

Miracle Learning Centre Chemistry Tuition Question on Extraction and Properties of Metals. (O Level Chemistry Tuition/ IP Chemistry Tuition)

1 Iron is extracted from its ore in a blast furnace. The raw materials in this process are iron ore, coke, limestone and air.

(a) Write an overall equation for the blast furnace process. _____________________________________________________________ (b) Describe the role of the following raw materials in this process. (i) limestone ________________________________________________ (ii) coke ________________________________________________ (c) Steel, an alloy of iron, is a very important structural material. What is a major disadvantage of using steel as a structural material? _____________________________________________________________ Miracle Learning Centre Answer to Chemistry Tuition Question on Extraction and Properties of Metals . (O Level Chemistry Tuition/ IP Chemistry Tuition) 1.a.i.Fe2O3 + 3CO  2Fe + 3CO2 1.b.i.limestone: decomposes to form lime (CaO) which reacts with the acidic impurities to form slag. b.ii.coke: reacts with oxygen to produce carbon monoxide which acts as the reducing agent. c.Iron in steel rusts relatively quickly. Learn from our Chemistry Tuition Questions and Answers. Miracle Learning Centre Call 6463 8756 or sms 8128 8342/9839 9908. (Specialist in Science and Maths) for Primary, Secondary and JC levels. Miracle Learning Centre specialises in Chemistry tuition, Physics tuition, Maths tuition and Science tuition Classes.

Miracle Learning Centre Chemistry Tuition Question on Bonding . (O Level Chemistry Tuition/ IP Chemistry Tuition)

1. In the table below are some data concerning some common elements and compounds. (The letters are not the symbols for these substances)

(a) State two pieces of evidence you would use to support the suggestion that substance C is a metal. _______________________________________________________________ _____________________________________________________________ (b) Substance B is dissolved in water and substance F is dissolved in sodium hydroxide solution. When both solutions are electrolysed in separate electrolysis cells, they form dark brown solutions at the anodes. On heating, both dark brown solutions give a purple vapour. Name the element which is common to B and F. _____________________________________________________________ (c) Substance F readily changes to this purple vapour as compared to substance B when heated. Explain why. _______________________________________________________________ _____________________________________________________________ Miracle Learning Centre Answer to Chemistry Tuition Question on Bonding . (O Level Chemistry Tuition/ IP Chemistry Tuition) 1a.Good conductor of electricity in molten and solid states. High melting point. 1b.Iodine. 1c.It is covalent (molecular) and would turn into vapour easily. Learn from our Chemistry Tuition Questions and Answers. Miracle Learning Centre Call 6463 8756 or sms 8128 8342/9839 9908. (Specialist in Science and Maths) for Primary, Secondary and JC levels. Miracle Learning Centre specialises in Chemistry tuition, Physics tuition, Maths tuition and Science tuition Classes.

Miracle Learning Centre Chemistry Tuition Question on Particulate Nature of Matter. (O Level Chemistry Tuition/ IP Chemistry Tuition)

1 Zinc nitrate, Zn(NO3)2 produces zinc oxide, oxygen gas and nitrogen dioxide gas when it is decomposed. (a) Write the balanced chemical equation for the reaction. _____________________________________________________________ (b) When nitrogen dioxide is cooled, it forms a yellow liquid and then pale yellow crystals. These crystals are heated and the temperature is measured every minute. The following graph can be drawn.

(i) Describe the arrangement and movement of the molecules in the region C – D. __________________________________________________________ (ii) Name the change that occurs in the region B – C. ________________________________________________________ (d) Nitrogen dioxide, oxygen and water react to form dilute nitric acid. Briefly describe how zinc nitrate crystals could be prepared from dilute nitric acid and zinc oxide. _______________________________________________________________ _______________________________________________________________ Miracle Learning Centre Answer to Chemistry Tuition Question on Particulate Nature of Matter. (O Level Chemistry Tuition/ IP Chemistry Tuition) 1a)2Zn(NO3)2  2ZnO + O2 + 4NO2 1b)The molecules are packed closely together and but are disorderly. The molecules are able to move throughout the liquid. 1c)Melting. 1d)1. Add zinc oxide to the hot acid and stir. 2. Remove the excess zinc oxide by filtering. 3. Heat the solution of zinc nitrate in an evaporating dish to produce a saturated solution and cool. 4. Filter the crystals and dry them by squeezing them between filter paper. Learn from our Chemistry Tuition Questions and Answers. Miracle Learning Centre Call 6463 8756 or sms 8128 8342/9839 9908. (Specialist in Science and Maths) for Primary, Secondary and JC levels. Miracle Learning Centre specialises in Chemistry tuition, Physics tuition, Maths tuition and Science tuition Classes.

Miracle Learning Centre Chemistry Tuition Question on Extraction and Properties of Metals . (O Level Chemistry Tuition/ IP Chemistry Tuition)

1. Titanium and nickel are transition metals. Some reactions of these two metals are given below. Titanium is extracted in a two-stage process from titanium (IV) chloride. Stage 1 – titanium(IV) oxide is heated with chlorine and carbon to form titanium (IV) chloride and carbon monoxide. Stage 2 - titanium (IV) chloride is heated with sodium in an atmosphere of argon to give pure titanium and sodium chloride. (a) (i) Construct the balance equation for stage 2. (ii) Calculate the mass of sodium required to react with 184 kg of titanium (IV) chloride. (b) Suggest why it is necessary to carry out the reaction of titanium (IV) chloride with sodium in an atmosphere of argon. (c) Titanium (IV) chloride is a liquid with a boiling point of 136.4°C. Suggest with a reason, the type of bonding in titanium (IV) chloride. (d) Titanium is expensive even though it is relatively abundant in the earth’s crust. Suggest a reason for this. In an experiment, small amounts of three metals were added to three aqueous metal nitrate solutions. The results are shown in the table.

(e) Predict the observations in (i) and (ii) when nickel is added to separate solutions of zinc nitrate and copper (II) nitrate. Write a chemical equation for one of the reactions that takes place. Miracle Learning Centre Answer to Chemistry Tuition Question on Extraction and Properties of Metals. (O Level Chemistry Tuition/ IP Chemistry Tuition) 1a.i.TiCl4 + 4Na Ti + 4NaCl a.ii.Mass of sodium = 1b. If air was present, sodium would oxidise./ To prevent sodium from reacting with oxygen in the air. 1c.Titanium (IV) chloride has covalent bonding as simple molecular compounds have low boiling points due to weak intermolecular bonds. 1d. Titanium chloride is extracted using sodium which is extracted using electrolysis which is a costly method. e.i.No reaction. e.ii.Blue solution went colourless and nickel coated with a silver solid. Ni (s) + Cu2+(aq)  Ni2+ (aq) + Cu (s) Learn from our Chemistry Tuition Questions and Answers. Miracle Learning Centre Call 6463 8756 or sms 8128 8342/9839 9908. (Specialist in Science and Maths) for Primary, Secondary and JC levels. Miracle Learning Centre specialises in Chemistry tuition, Physics tuition, Maths tuition and Science tuition Classes.

Miracle Learning Centre Chemistry Tuition Question on Mole Concept. (O Level Chemistry Tuition/ IP Chemistry Tuition)

1. Steel pans sometimes blacken because of the sulfur coming from the proteins in eggs reacting with ions to form iron (II) sulfide. The equation for the reaction is shown below. Fe (s) + S (s)  FeS (s) What mass of iron (II) sulfide is formed from using the pans to fry a hundred eggs each containing 0.032 g of sulfur? A 0.88 g B 8.8 g C 88 g D 5.6 g

2. A solution contains 8.20 g/dm3 of the acid H3ZO3. 25.0 cm3 of this solution reacted with an equal volume of 0.100 mol/dm3 NaOH. The equation for the reaction was NaOH + H3ZO3  NaH2ZO3 + H2O What is element Z? A nitrogen B phosphorus C silicon D sulfur

3. An aqueous solution of a salt was placed in a test tube and sodium hydroxide was added from a burette. The height of the precipitate formed in the tube was measured from various volumes of alkali added and a graph was shown below: height of precipitate volume of alkali added Which of the following salts would show this behaviour? I aluminium sulfate II zinc sulfate III ammonium sulfate A I only B I and II only C II and III only D I, III and III

Miracle Learning Centre Answer to Chemistry Tuition Question on Mole Concept . (O Level Chemistry Tuition/ IP Chemistry Tuition) 1.B 2.B 3.B Learn from our Chemistry Tuition Questions and Answers. Miracle Learning Centre Call 6463 8756 or sms 8128 8342/9839 9908. (Specialist in Science and Maths) for Primary, Secondary and JC levels. Miracle Learning Centre specialises in Chemistry tuition, Physics tuition, Maths tuition and Science tuition Classes.

Miracle Learning Centre Chemistry Tuition Question on Extraction and Properties of Metals. (O Level Chemistry Tuition/ IP Chemistry Tuition)

1. Zinc displaces iron from aqueous iron (II) sulfate because A zinc has a higher proton number than iron. B zinc atoms lose electrons more readily than iron atom. C zinc atoms can oxidise Fe2+ ions to Fe atoms. D zinc sulfate is more soluble than iron (II) sulfate.

2. Aluminium metal does not corrode easily because A it does not react with air. B an oxide layer protects the metal. C it is low in the reactivity series. D it reacts with water to form a protective layer of hydrogen.

3. Different forms of steel contain differing amounts of carbon. Steel S1 contains a high proportion of carbon. Steel S2 contains a low proportion of carbon. Which statement is correct? A S1 is stronger but more brittle than S2. B S1 is stronger but less brittle than S2. C S1 is less strong but more brittle than S2. D S1 is less strong but less brittle than S2. Miracle Learning Centre Answer to Chemistry Tuition Question on Extraction and Properties of Metals. (O Level Chemistry Tuition/ IP Chemistry Tuition) 1.B 2.B 3.A Learn from our Chemistry Tuition Questions and Answers. Miracle Learning Centre Call 6463 8756 or sms 8128 8342/9839 9908. (Specialist in Science and Maths) for Primary, Secondary and JC levels. Miracle Learning Centre specialises in Chemistry tuition, Physics tuition, Maths tuition and Science tuition Classes.

Miracle Learning Centre Science Tuition Question on Enzyme.

(a) Fig. 1.1 shows apparatus at the start of an experiment to investigate the digestion of an emulsion of fat droplets in water by enzyme A.

The pH indicator is green in a pH of 7, blue when the pH is above 7 and red when it is below 7. The apparatus is kept at 40 °C for 20 minutes during which time the indicator changes from green to red. (i) State the identity of enzyme A. _____________________________ (ii) Explain why the apparatus was kept at 40 °C. _________________________________________________________ _________________________________________________________ _______________________________________________________ (b) Name the products of digestion of the emulsion by enzyme A. _____________________________________________________________ (c) Describe the processes which led to the change in pH. _______________________________________________________________ _______________________________________________________________ _______________________________________________________________ _______________________________________________________________ _______________________________________________________________ ____________________________________________________________ 2 (a) Explain the “lock and key” theory of enzyme action. Miracle Learning Centre Answer to Science Tuition Question on Enzyme (O Level Science Tuition/IP Science Tuition/Secondary Science Tuition) 1 (a) (i) State the identity of enzyme A. Lipase (ii) Explain why the apparatus was kept at 40 °C. optimum temperature + for enzyme/lipase action (b) Name the products of digestion of the emulsion by enzyme A. fatty acids + glycerol (c) Describe the processes which led to the change in pH. fatty acids/ref. smaller molecules (can) pass through partially permeable membrane/Visking tubing down a concentration gradient/ by diffusion acidity of or lowers pH of water/ref acidity of molecules changes the pH indicator [max 3] 2 (a) ref enzyme – lock/ active site; ref substrate – key; key fits lock / ref. Shape/ size/ specificity; ref enzyme-substrate complex; reaction while key in lock; products formed. [max 5] Learn from our Science Tuition Questions and Answers. Miracle Learning Centre Call 6463 8756 or sms 8128 8342/9839 9908. (Specialist in Science and Maths) for Primary, Secondary and JC levels. Miracle Learning Centre specialises in Science tuition, Maths tuition, Chemistry tuition and Physics tuition classes.

Miracle Learning Centre Science Tuition Question on DNA. (O Level Science Tuition/IP Science Tuition/Secondary Science Tuition)

1 (a) The diagram shows a section of a DNA molecule.

The letters A and G represent 2 of the bases present in the molecule. Describe the structure of DNA. In your answer, you should clearly identify each of the labelled structures. _______________________________________________________________ _______________________________________________________________ _______________________________________________________________ _______________________________________________________________ ____________________________________________________________ (b) DNA is an information storage molecule. The organic bases present in DNA allow DNA to store information about the sequence of amino acids in a protein. Explain how it acts as an information storage molecule. . _______________________________________________________________ _______________________________________________________________ _______________________________________________________________ ____________________________________________________________

2) Fig. 6.1 shows the four stages of mitosis in an animal cell.

(a) Using the letters P, Q, R and S, list the correct order of the stages. …………………………………………………………………………………... (b) Name the stages. P ………………………………………. Q …………………………………….. R ……………………………………… S ................................................. (c) What is the diploid number of chromosomes in this cell? …………………………………………………………………………………... (d) Describe the characteristics of the resulting daughter cells at the end of the process and state the significance of this to the organism. Characteristics: ………………………………………………………………….. ……………………………………………………………………………………… ………………………………………………………………………………...... significance: ……………………………………………………………………… ……………………………………………………………………………………… ……………………………………………………………………………………… ………………………………………………………………………………...... Miracle Learning Centre Answer to Science Tuition Question on DNA. (O Level Science Tuition/IP Science Tuition/Secondary Science Tuition) 1 (a) The diagram shows a section of a DNA molecule. The letters A and G represent 2 of the bases present in the molecule. Describe the structure of DNA. In your answer, you should clearly identify each of the labelled structures. 1 DNA molecule made up of two chains/ is a double helix; 2 4 bases: Adenine, guanine, cytosine and thymine 3 A with T; G with C; 4 Held by hydrogen bonds (Y); 5 X is made of sugar and phosphate. [max. 4] (b) DNA is an information storage molecule. The organic bases present in DNA allow DNA to store information about the sequence of amino acids in a protein. Explain how it acts as an information storage molecule. The sequence of bases determines the sequence of amino acids; Three bases code for one amino acid; 2) Fig. 6.1 shows the four stages of mitosis in an animal cell.

(a) Using the letters P, Q, R and S, list the correct order of the stages. Q, P, S and R (b) Name the stages. P: metaphase Q: prophase R: telophase S: anaphase (c) What is the diploid number of chromosomes in this cell? Diploid no. = 4 (d) Describe the characteristics of the resulting daughter cells at the end of the process and state the significance of this to the organism. Characteristics: - the resulting daughter cells are genetically identical to each other; significance: ANY TWO OF THE FOLLOWING: - to increase the number of cells within an organism for growth; - for cell replacement / regeneration of tissues which are damaged or dying such as those lining the stomach wall or in the skin; - or for asexual reproduction; Learn from our Science Tuition Questions and Answers. Miracle Learning Centre Call 6463 8756 or sms 8128 8342/9839 9908. (Specialist in Science and Maths) for Primary, Secondary and JC levels. Miracle Learning Centre specialises in Science tuition, Maths tuition, Chemistry tuition and Physics tuition classes.

Miracle Learning Centre Science Tuition Question on Circulatory System (O Level Science Tuition/IP Science Tuition/Secondary Science Tuition)

Fig. 3.1 shows three stages in the cardiac cycle.

(a) (i) Name the blood vessels labelled F and G. F __________________________________ G __________________________________ (ii) Explain why the walls of the atria have thinner muscle than the walls of the ventricles. _________________________________________________________ _________________________________________________________ _________________________________________________________ _____________________________________________________ (b) Describe what is happening to the following parts of the left side of the heart at stage K as shown in Fig. 3.1: • left atrium • left ventricle • aortic valve. _______________________________________________________________ _______________________________________________________________ _______________________________________________________________ _______________________________________________________________ _______________________________________________________________ (c) Letters A to F below refer to events which occur during a cardiac cycle. Put the letters into the boxes to show the correct sequence. The first one has been done for you. A Semi-lunar valves open B Blood enters the atria C Ventricles contract D Atrioventricular valves open E Blood flows into the ventricles F Atria contract Answer: B _______________ _____ _____ (d) Atrial Septal Defect (ASD) is a condition in which there is a hole in the wall separating the left and right atria. Explain how this will affect the flow of blood through the heart and suggest some of the possible effects of this condition. _______________________________________________________________ _______________________________________________________________ _______________________________________________________________ _______________________________________________________________ _______________________________________________________________ ____________________________________________________________ Miracle Learning Centre Answer to Science Tuition Question on Circulatory System. (O Level Science Tuition/IP Science Tuition/Secondary Science Tuition) 1 (a) (i) Name the blood vessels labelled F and G. F inferior vena cava G pulmonary artery (ii) Explain why the walls of the atria have thinner muscle than the walls of the ventricles. ventricles pump blood to further organs ( to lungs/to whole body); atria pump blood, to ventricles/shorter distance; correct reference to pressure; e.g. ventricles have to push blood further so blood under higher pressure or create higher pressure R atria at lower pressure or ventricles receive blood at higher pressure (b) Describe what is happening to the following parts of the left side of the heart at stage K as shown in Fig. 3.1: • left atrium • left ventricle • aortic valve.

(c) Answer: BFDECA (d) Atrial Septal Defect (ASD) is a condition in which there is a hole in the wall separating the left and right atria. Explain how this will affect the flow of blood through the heart and suggest some of the possible effects of this condition. 1 blood passes from left to right atria 2 because of higher pressure in left atrium 3 mixing of oxygenated and deoxygenated blood 4 blood would flow from right atrium to right ventricle to lungs 5 there would be more than excess blood to the lungs (due to increased pressure from right ventricle) [4points] Effects: 6 high blood pressure in lungs 7 enlargement and weakening of right atria and ventricle/ heart failure 8 shortness of breath; 9 fainting/ fatigue [2 points] Learn from our Science Tuition Questions and Answers. Miracle Learning Centre Call 6463 8756 or sms 8128 8342/9839 9908. (Specialist in Science and Maths) for Primary, Secondary and JC levels. Miracle Learning Centre specialises in Science tuition, Maths tuition, Chemistry tuition and Physics tuition classes.

Miracle Learning Centre Chemistry Tuition Question on Mole Concept. (O Level Chemistry Tuition/ IP Chemistry Tuition)

1. Steel pans sometimes blacken because of the sulfur coming from the proteins in eggs reacting with ions to form iron (II) sulfide. The equation for the reaction is shown below. Fe (s) + S (s)  FeS (s) What mass of iron (II) sulfide is formed from using the pans to fry a hundred eggs each containing 0.032 g of sulfur? A 0.88 g B 8.8 g C 88 g D 5.6 g

2. A solution contains 8.20 g/dm3 of the acid H3ZO3. 25.0 cm3 of this solution reacted with an equal volume of 0.100 mol/dm3 NaOH. The equation for the reaction was NaOH + H3ZO3  NaH2ZO3 + H2O What is element Z? A nitrogen B phosphorus C silicon D sulfur

3. An aqueous solution of a salt was placed in a test tube and sodium hydroxide was added from a burette. The height of the precipitate formed in the tube was measured from various volumes of alkali added and a graph was shown below: height of precipitate volume of alkali added Which of the following salts would show this behaviour? I aluminium sulfate II zinc sulfate III ammonium sulfate A I only B I and II only C II and III only D I, III and III

Miracle Learning Centre Answer to Chemistry Tuition Question on Mole Concept . (O Level Chemistry Tuition/ IP Chemistry Tuition) 1.B 2.B 3.B Learn from our Chemistry Tuition Questions and Answers. Miracle Learning Centre Call 6463 8756 or sms 8128 8342/9839 9908. (Specialist in Science and Maths) for Primary, Secondary and JC levels. Miracle Learning Centre specialises in Chemistry tuition, Physics tuition, Maths tuition and Science tuition Classes.

Miracle Learning Centre Chemistry Tuition Question on Redox Reactions. (O Level Chemistry Tuition/ IP Chemistry Tuition)

1. The exhaled breath of diabetics contains propanol. A medical student wishes to test for diabetes by asking patients to bubble their breath through a reagent. Which reagent could be used? A aqueous bromine B acidified potassium dichromate (VI) solution C universal indicator D aqueous potassium iodide

2. In the following reaction: MnO2 + 4HCl  MnCl2 + 2H2O + Cl2 The substance HCl is reacting as A a catalyst. B a dehydrating agent. C an oxidising agent. D a reducing agent.

3. In which of the following is the oxidation number (oxidation state) of chromium greater than that of manganese? A K2Cr2O7 MnO4 B Cr2O3 MnO2 C K2CrO4 KMnO4 D Cr2(SO4)3 MnSO4 Miracle Learning Centre Answer to Chemistry Tuition Question on Redox Reactions. (O Level Chemistry Tuition/ IP Chemistry Tuition) 1.B 2.C 3.D Learn from our Chemistry Tuition Questions and Answers. Miracle Learning Centre Call 6463 8756 or sms 8128 8342/9839 9908. (Specialist in Science and Maths) for Primary, Secondary and JC levels. Miracle Learning Centre specialises in Chemistry tuition, Physics tuition, Maths tuition and Science tuition Classes.

Miracle Learning Centre Chemistry Tuition Question on Extraction and Properties of Metals . (O Level Chemistry Tuition/ IP Chemistry Tuition)

1. Titanium and nickel are transition metals. Some reactions of these two metals are given below. Titanium is extracted in a two-stage process from titanium (IV) chloride. Stage 1 – titanium(IV) oxide is heated with chlorine and carbon to form titanium (IV) chloride and carbon monoxide. Stage 2 - titanium (IV) chloride is heated with sodium in an atmosphere of argon to give pure titanium and sodium chloride. (a) (i) Construct the balance equation for stage 2. (ii) Calculate the mass of sodium required to react with 184 kg of titanium (IV) chloride. (b) Suggest why it is necessary to carry out the reaction of titanium (IV) chloride with sodium in an atmosphere of argon. (c) Titanium (IV) chloride is a liquid with a boiling point of 136.4°C. Suggest with a reason, the type of bonding in titanium (IV) chloride. (d) Titanium is expensive even though it is relatively abundant in the earth’s crust. Suggest a reason for this.

In an experiment, small amounts of three metals were added to three aqueous metal nitrate solutions. The results are shown in the table.

Predict the observations in (i) and (ii) when nickel is added to separate solutions of zinc nitrate and copper (II) nitrate. Write a chemical equation for one of the reactions that takes place. Miracle Learning Centre Answer to Chemistry Tuition Question on Extraction and Properties of Metals. (O Level Chemistry Tuition/ IP Chemistry Tuition) 1a.i.TiCl4 + 4Na Ti + 4NaCl a.ii.Mass of sodium = 1b. If air was present, sodium would oxidise./ To prevent sodium from reacting with oxygen in the air. 1c.Titanium (IV) chloride has covalent bonding as simple molecular compounds have low boiling points due to weak intermolecular bonds. 1d. Titanium chloride is extracted using sodium which is extracted using electrolysis which is a costly method. e.i.No reaction. e.ii.Blue solution went colourless and nickel coated with a silver solid. Ni (s) + Cu2+(aq)  Ni2+ (aq) + Cu (s) Learn from our Chemistry Tuition Questions and Answers. Miracle Learning Centre Call 6463 8756 or sms 8128 8342/9839 9908. (Specialist in Science and Maths) for Primary, Secondary and JC levels. Miracle Learning Centre specialises in Chemistry tuition, Physics tuition, Maths tuition and Science tuition Classes.

Miracle Learning Centre Chemistry Tuition Question on Particulate Nature of Matter. (O Level Chemistry Tuition/ IP Chemistry Tuition)

1 Zinc nitrate, Zn(NO3)2 produces zinc oxide, oxygen gas and nitrogen dioxide gas when it is decomposed. (a) Write the balanced chemical equation for the reaction. _____________________________________________________________ (b) When nitrogen dioxide is cooled, it forms a yellow liquid and then pale yellow crystals. These crystals are heated and the temperature is measured every minute. The following graph can be drawn.

(i) Describe the arrangement and movement of the molecules in the region C – D. __________________________________________________________ (ii) Name the change that occurs in the region B – C. ________________________________________________________ (d) Nitrogen dioxide, oxygen and water react to form dilute nitric acid. Briefly describe how zinc nitrate crystals could be prepared from dilute nitric acid and zinc oxide. _______________________________________________________________ _______________________________________________________________ Miracle Learning Centre Answer to Chemistry Tuition Question on Particulate Nature of Matter. (O Level Chemistry Tuition/ IP Chemistry Tuition) 1a)2Zn(NO3)2  2ZnO + O2 + 4NO2 1b)The molecules are packed closely together and but are disorderly. The molecules are able to move throughout the liquid. 1c)Melting. 1d)1. Add zinc oxide to the hot acid and stir. 2. Remove the excess zinc oxide by filtering. 3. Heat the solution of zinc nitrate in an evaporating dish to produce a saturated solution and cool. 4. Filter the crystals and dry them by squeezing them between filter paper. Learn from our Chemistry Tuition Questions and Answers. Miracle Learning Centre Call 6463 8756 or sms 8128 8342/9839 9908. (Specialist in Science and Maths) for Primary, Secondary and JC levels. Miracle Learning Centre specialises in Chemistry tuition, Physics tuition, Maths tuition and Science tuition Classes.

Miracle Learning Centre Chemistry Tuition Question on Bonding . (O Level Chemistry Tuition/ IP Chemistry Tuition)

In the table below are some data concerning some common elements and compounds. (The letters are not the symbols for these substances)

(a) State two pieces of evidence you would use to support the suggestion that substance C is a metal. _______________________________________________________________ _____________________________________________________________ (b) Substance B is dissolved in water and substance F is dissolved in sodium hydroxide solution. When both solutions are electrolysed in separate electrolysis cells, they form dark brown solutions at the anodes. On heating, both dark brown solutions give a purple vapour. Name the element which is common to B and F. _____________________________________________________________ (c) Substance F readily changes to this purple vapour as compared to substance B when heated. Explain why. _______________________________________________________________ _____________________________________________________________ Miracle Learning Centre Answer to Chemistry Tuition Question on Bonding . (O Level Chemistry Tuition/ IP Chemistry Tuition) 1a.Good conductor of electricity in molten and solid states. High melting point. 1b.Iodine. 1c.It is covalent (molecular) and would turn into vapour easily. Learn from our Chemistry Tuition Questions and Answers. Miracle Learning Centre Call 6463 8756 or sms 8128 8342/9839 9908. (Specialist in Science and Maths) for Primary, Secondary and JC levels. Miracle Learning Centre specialises in Chemistry tuition, Physics tuition, Maths tuition and Science tuition Classes.

Miracle Learning Centre Chemistry Tuition Question on Extraction and Properties of Metals. (O Level Chemistry Tuition/ IP Chemistry Tuition)

1 Iron is extracted from its ore in a blast furnace. The raw materials in this process are iron ore, coke, limestone and air.

(a) Write an overall equation for the blast furnace process. _____________________________________________________________ (b) Describe the role of the following raw materials in this process. (i) limestone ________________________________________________ (ii) coke ________________________________________________ (c) Steel, an alloy of iron, is a very important structural material. What is a major disadvantage of using steel as a structural material? _____________________________________________________________ Miracle Learning Centre Answer to Chemistry Tuition Question on Extraction and Properties of Metals . (O Level Chemistry Tuition/ IP Chemistry Tuition) 1.a.i.Fe2O3 + 3CO  2Fe + 3CO2 1.b.i.limestone: decomposes to form lime (CaO) which reacts with the acidic impurities to form slag. b.ii.coke: reacts with oxygen to produce carbon monoxide which acts as the reducing agent. c.Iron in steel rusts relatively quickly. Learn from our Chemistry Tuition Questions and Answers. Miracle Learning Centre Call 6463 8756 or sms 8128 8342/9839 9908. (Specialist in Science and Maths) for Primary, Secondary and JC levels. Miracle Learning Centre specialises in Chemistry tuition, Physics tuition, Maths tuition and Science tuition Classes.

Miracle Learning Centre Chemistry Tuition Question on Periodic Table . (O Level Chemistry Tuition/ IP Chemistry Tuition)

1. Use the information in the table to answer the questions below. (You may use a letter once, more than once or not at all.)

(a) Which element could be hydrogen ? Give a reason for your choice. …………………………………………………………………………………………. …………………………………………………………………………………………. …………………………………………………………………………………………. (b) Which two elements are in the same Group of the Periodic Table ? Give a reason for your choice. …………………………………………………………………………………………. …………………………………………………………………………………………. (c) Using columns 3 and 4, calculate the mass of 1 mole of M and identify M ……………………………………………………………………………..……………. …………………………………………………………………………………………. …………………………………………………………………………………… (d) Give two observations you might make when element R is added to a dilute hydrochloric acid. ……………………………………………………………………………..……………. …………………………………………………………………………………………. …………………………………………………………………………………… Miracle Learning Centre Answer to Chemistry Tuition Question on Periodic Table . (O Level Chemistry Tuition/ IP Chemistry Tuition) 1. a. A. 24 dm3 of A weighs 24 x 0.08 g i.e. approx = 2 g b. G and J They have the same valency, one, towards oxygen and form oxides of similar formula c. Mass of one mole of M = 3 x 15 = 45 g Scandium d. There is an effervescence forming a colourless and odourless gas A pale green solution formed. Element R becomes smaller in size

Learn from our Chemistry Tuition Questions and Answers. Miracle Learning Centre Call 6463 8756 or sms 8128 8342/9839 9908. (Specialist in Science and Maths) for Primary, Secondary and JC levels. Miracle Learning Centre specialises in Chemistry tuition, Physics tuition, Maths tuition and Science tuition Classes.

Miracle Learning Centre Chemistry Tuition Question on Extraction and Properties of Metals . (O Level Chemistry Tuition/ IP Chemistry Tuition)

Miracle Learning Centre Answer to Chemistry Tuition Question on Extraction and Properties of Metals . (O Level Chemistry Tuition/ IP Chemistry Tuition) 1)A 2)D 3)C Learn from our Chemistry Tuition Questions and Answers. Miracle Learning Centre Call 6463 8756 or sms 8128 8342/9839 9908. (Specialist in Science and Maths) for Primary, Secondary and JC levels. Miracle Learning Centre specialises in Chemistry tuition, Physics tuition, Maths tuition and Science tuition Classes.

Miracle Learning Centre Physics Tuition Question on Temperature. (O Level Physics Tuition / IP Physics Tuition)

1. The length of the mercury thread is found to be 6 cm and 20 cm at 0oC and 70oC respectively on an ungraduated thermometer. (a) State the temperature that correspond to a length of 10 cm.

Temperature = __________ State the length of the mercury thread that corresponds to the steam point.

Length = ___________

Miracle Learning Centre Answer to Physics Tuition Question on Temperature. (O Level Physics Tuition / IP Physics Tuition) 1 (a) 14 cm rep 70 oC 4 cm rep (70/14) x 4 = 20oC (b) 70 oC rep 14 cm 1000C rep (14/70)x 100 = 20 cm Length = 20 + 6 = 26 cm Learn from our Physics Tuition Questions and Answers. Miracle Learning Centre Call 6463 8756 or sms 8128 8342/9839 9908. (Specialist in Science and Maths) for Primary, Secondary and JC levels. Miracle Learning Centre specialises in Physics tuition, Chemistry tuition, Maths tuition and Science tuition Classes.

Miracle Learning Centre Science Tuition Question on Kinetic Theory. (O Level Science Tuition/IP Science Tuition/Secondary Science Tuition)

1. The diagram shows a car traveling at a constant speed of 30 m/s on a level road. At this speed the car has to overcome a total force of 600 N opposing the car.

a) State the value of the driving force produced by the engine for a constant speed of 30 m/s. _________________________________________________________ b) Explain why the car slows down when it climbs a hill, even though the driving force is unchanged. _________________________________________________________ _________________________________________________________ _________________________________________________________ c) When on the level road and travelling at 30 m/s, the driving force is removed and the car starts to decelerate. If the mass of the car is 800 kg, calculate the deceleration of the car due to the opposing force. 2. A gas in an enclosed container is heated uniformly. Assuming the volume of the container is constant, use the kinetic theory to explain the effect of this heating on the pressure which the gas exerts on the container. _______________________________________________________________ _______________________________________________________________ _______________________________________________________________ _______________________________________________________________ _______________________________________________________________ _______________________________________________________________ _______________________________________________________________ _______________________________________________________________ Miracle Learning Centre Answer to Science Tuition Question on Kinetic Theory. (O Level Science Tuition/IP Science Tuition/Secondary Science Tuition) 1. a) 600 N b) Some of the kinetic energy is converted into gravitational potential energy. c) Deceleration = Retarding Force / mass = 600 / 800 = 0.75 m/s2 2. When the gas in a container is heated, the gas particles gain kinetic energy and move more rapidly. Thus, they hit against the walls of the container with greater force AND greater frequency. As p = F/A, the pressure exerted on the walls of the container rises. Learn from our Science Tuition Questions and Answers. Miracle Learning Centre Call 6463 8756 or sms 8128 8342/9839 9908. (Specialist in Science and Maths) for Primary, Secondary and JC levels. Miracle Learning Centre specialises in Science tuition, Maths tuition, Chemistry tuition and Physics tuition classes.

Miracle Learning Centre Science Tuition Question on Turning Effects of Force. (O Level Science Tuition/IP Science Tuition/Secondary Science Tuition)

1. Fig (a) and Fig (b) show cranes carrying similar loads but with different orientations of the arm.

a) Which of the above figures allow a greater load to be carried without the crane tilting to the right? Explain your answer. _________________________________________________________ _________________________________________________________ b) The load has a weight of 800 N. The load needs to be turned upright by applying the force F with the load turning about point A as shown in Fig (c). You can assume that the centre of mass is located at the centre of the load.

(i) Calculate the mass of the load. (ii) Calculate the minimum force F needed to just turn the load about point A.

(a) The diagram shows a mass moving at a steady speed of 0.1 m s-1 when the applied force F is 12 N. (i) Draw in the other horizontal force which is acting on the mass and indicate its line of action and magnitude. (ii) Calculate the work done in moving the mass 1.5 m along the surface. (b) Force F is now increased to 18 N and acts for 0.2 s. Assuming that all other forces remain constant, calculate (i) the acceleration produced, (ii) the highest speed reached. Miracle Learning Centre Answer to Science Tuition Question on Turning Effects of Force. (O Level Science Tuition/IP Science Tuition/Secondary Science Tuition) 1. a) Fig (b) as the perpendicular distance of the load to the pivot is smaller than in Fig (a). b) (i) Mass = 80 kg (ii) Anticlockwise moments = Clockwise moments F x 0.6 = 800 x 0.5 F = 667 N

(aii) Work done = F x s = 12 x 1.5 = 18 J (bi) Resultant force = 18-12 = 6 N A = Resultant/mass = 6/3 = 2m/s2 © Highest speed = u + at [1]= 0.1 + 2x 0.2 = 0.5 m/s Learn from our Science Tuition Questions and Answers. Miracle Learning Centre Call 6463 8756 or sms 8128 8342/9839 9908. (Specialist in Science and Maths) for Primary, Secondary and JC levels. Miracle Learning Centre specialises in Science tuition, Maths tuition, Chemistry tuition and Physics tuition classes.

Miracle Learning Centre Science Tuition Question on Pressure (O Level Science Tuition/IP Science Tuition/Secondary Science Tuition)

1. The hydraulic system shown in the diagram below contains an incompressible liquid. A downward force of 3 N is exerted on the smaller piston.

Calculate (a) the pressure, in Pa, exerted by the 3 N force (b) the magnitude of the force X that is necessary to balance the system. 2) Amy is worried about burglars. She puts a pressure sensor on the floor near her front door. She is going to connect the sensor to an alarm circuit. The alarm will make a noise when someone treads on the sensor. Amy studies the data sheet that comes with the sensor. She finds the graph shown below.

(a) Write down the equation for calculating pressure. ………………………………………………………………………………….. (b)Amy has a weight of 600 N. If the sensor has an area of 30 cm2, calculate the pressure on the sensor in N/cm2, when she stands on the whole sensor barefoot. pressure = …………………….. (c)Use the graph to find the resistance of the sensor when Amy stands on it. resistance = …………………….. (d) Suppose the alarm will only ring when someone treads on the whole sensor barefoot with a minimum pressure of 18 N/cm2. Explain why her pressure sensor may not be practical. …………………………………………………………………………………….. ………………………………………………………………………………….. Miracle Learning Centre Answer to Science Tuition Question on Pressure (O Level Science Tuition/IP Science Tuition/Secondary Science Tuition) 1a) p = F/A = 3 / 0.0002 = 15 000 Pa b) Force X = p A = 15 000 x 0.0006 = 9 N 2) Amy is worried about burglars. She puts a pressure sensor on the floor near her front door. She is going to connect the sensor to an alarm circuit. The alarm will make a noise when someone treads on the sensor. Amy studies the data sheet that comes with the sensor. She finds the graph shown below.

(a) Write down the equation for calculating pressure. P = F / A (b) Amy has a weight of 600 N. if the sensor has an area of 30 cm2, calculate the pressure on the sensor in N/cm2, when she stands on the sensor. pressure = …………………….. (c) Use the graph to find the resistance of the sensor when Amy stands on it. resistance = …………………….. (d)Suppose the alarm will only ring when someone treads on the sensor with a minimum pressure of 18 N/cm2. Explain why her pressure sensor may not be practical. For the alarm to work, the person stepping on the sensor must be at least 540 N. If the person is lighter, the sensor would not work. Learn from our Science Tuition Questions and Answers. Miracle Learning Centre Call 6463 8756 or sms 8128 8342/9839 9908. (Specialist in Science and Maths) for Primary, Secondary and JC levels. Miracle Learning Centre specialises in Science tuition, Maths tuition, Chemistry tuition and Physics tuition classes.

Miracle Learning Centre Maths Tuition Question on Probability. (O Level Maths Tuition/IP Maths Tuition/Secondary Maths Tuition)

1. A bowl of sweets contains 12 chocolate nuggets, 13 mints and 15 toffees. Mr Chan takes two sweets at random and eats them. (a) Draw a tree diagram to represent all the possible outcome. (b) Calculate the probability, as a fraction in its simplest form, that i) a chocolate nugget and a mint was taken. ii) none of the two sweets chosen were toffees. (c) A third sweet was randomly taken from the bowl. Calculate the probability that the first two sweets drawn were of the same type and the third was a chocolate nugget. Miracle Learning Centre Answer to Maths Tuition Question on Probability. (O Level Maths Tuition/IP Maths Tuition/Secondary Maths Tuition)

bi) P(that to get chocolate and mint) =12 40 × 13 39 + 13 40 × 12 39 = 15 bii) P(none of the two sweets are toffees) = 12 40 × 24 39 + 13 40 × 24 39 = 5 13 (c) P(two sweets of the same type and the third a chocolate nugget) =12 40 × 11 39 × 10 38 + 13 40 × 12 39 × 12 38 + 15 40 × 14 39 × 12 38 = 119 1235 Learn from our Maths Tuition Questions and Answers. Miracle Learning Centre Call 6463 8756 or sms 8128 8342/9839 9908. (Specialist in Science and Maths) for Primary, Secondary and JC levels. Miracle Learning Centre specialises in Maths tuition, Science tuition, Chemistry tuition and Physics tuition classes.

Miracle Learning Centre Maths Tuition Question on Trigonometry. (O Level Maths Tuition/IP Maths Tuition/Secondary Maths Tuition)

1. ACF is a vertical wall. The angle of depression of a boy at B from the top of the wall, A, is 63˚. Calculate (a) the distance between the boy and the foot of the wall, F, (b) the angle of elevation of a point C on the wall, 4 m above F, from the boy at B.

Miracle Learning Centre Answer to Maths Tuition Question on Trigonometry. (O Level Maths Tuition/IP Maths Tuition/Secondary Maths Tuition) 1.(a) BAF = 90˚ - 63˚ = 27˚ tan 27˚ = BF = 3.06 m (3sf) 1(b) tan CBF = CBF = 52.6˚ (1dp) Learn from our Maths Tuition Questions and Answers. Miracle Learning Centre Call 6463 8756 or sms 8128 8342/9839 9908. (Specialist in Science and Maths) for Primary, Secondary and JC levels. Miracle Learning Centre specialises in Maths tuition, Science tuition, Chemistry tuition and Physics tuition classes.

Miracle Learning Centre Science Tuition Question on Circulatory System. (O Level Science Tuition/IP Science Tuition/Secondary Science Tuition) 1 Fig. 1.1 shows the changes in blood pressure (A), velocity (B) and cross sectional area (C) of the blood vessels of the systemic circulation as blood flows and returns to the heart.

(a) State the relationship between the velocity of the blood and the total cross sectional area of the blood vessels. (b) (i) Comment on the rate of blood flow through the capillaries. (ii) Explain the importance of this in relation to the function of the capillaries. (c) Explain how the velocity of blood (i) is maintained in the arteries, despite fluctuations in blood pressure, (ii) in the veins increases, while the blood pressure continues to fall. 2(a) Fig. 5.1 shows how a blocked blood vessel in the heart can be by-passed using an artificial blood vessel. Fig 5.1

(i) Name the blocked blood vessel. (ii) Identify structures P and Q on Fig. 5.1. P -------------------------------------- Q ---------------------------------------- b) Sometimes, instead of an artificial blood vessel being used for the graft, a vein is taken from elsewhere in the patient’s body. Suggest two ways in which a vein might not be as suitable for carrying blood to the heart muscle as the blood vessel in the heart before it became blocked.

c) Fig. 5.2 shows the same blood vessel, as in (a)(i) but this time the blockage is being treated with the use of a ‘stent’.

(i) Name two components of the material that is causing the blockage at R.

(ii) Suggest and explain why patients are given ‘anti-platelet’ drugs before inserting the stent. Miracle Learning Centre Answer to Science Tuition Question on Circulatory System. (O Level Science Tuition/IP Science Tuition/Secondary Science Tuition)

Learn from our Science Tuition Questions and Answers. Miracle Learning Centre Call 6463 8756 or sms 8128 8342/9839 9908. (Specialist in Science and Maths) for Primary, Secondary and JC levels. Miracle Learning Centre specialises in Science tuition, Maths tuition, Chemistry tuition and Physics tuition classes.

Miracle Learning Centre Science Tuition Question on Cells. (O Level Science Tuition/IP Science Tuition/Secondary Science Tuition) 1 Fig. 1.1 shows five types of cells.

(a) Identify cells A, B and C. A …………………………………………………… B …………………………………………………… C …………………………………………………… (b) What is the function of cell C? ……………………………………………………………………………………… ………………………………………………………………………………….. (c) State two ways by which cell E can be recognized as a plant cell. 1 ………………………………………………………………………………….. ………………………………………………………………………………….. 2 ………………………………………………………………………………….. ………………………………………………………………………………. 2 (a) Explain how structure and function are related with reference to the following cell types: (i) Palisade mesophyll cells (ii) Xylem vessels [7] (b) How differently does a palisade mesophyll cell behave from a human cheek cell when both are placed in concentrated sucrose solutions? [3] Miracle Learning Centre Answer to Science Tuition Question on Cells (O Level Science Tuition/IP Science Tuition/Secondary Science Tuition) 1) Fig. 1.1 shows five types of cells.

(a) Identify cells A, B and C. A: xylem vessels B: sperm C: red blood cell (b) What is the function of cell C? - transport of oxygen; - from lungs to all parts of body; (c) State two ways by which cell E can be recognized as a plant cell. 1 presence of cellulose cell wall; and/or 2 presence of chloroplasts; and/or ANY TWO presence of large central vacuole;

Learn from our Science Tuition Questions and Answers. Miracle Learning Centre Call 6463 8756 or sms 8128 8342/9839 9908. (Specialist in Science and Maths) for Primary, Secondary and JC levels. Miracle Learning Centre specialises in Science tuition, Maths tuition, Chemistry tuition and Physics tuition classes.