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

1) Germanium is an element in Group IV. a) It has a similar macromolecular structure to diamond. Predict two physical properties of germanium. _______________________________________________________ ______________________________________________________
b) Explain why graphite, which is also a macromolecular form of carbon, has different physical properties to diamond and germanium. ________________________________________________________ ________________________________________________________
c) The electron distribution of a germanium atom is 2, 8, 18, 4. Draw a diagram to show the arrangement of the outermost shell electrons in the compound germanium tetrachloride. Use o to represent an electron from germanium. Use x to represent an electron from chlorine.
d) Germanium forms a series of saturated compounds with hydrogen which resemble the alkanes. i) Predict the general molecular formula of these compounds of germanium and hydrogen. ___________________________________________________ ii) Draw the structural formula for one of the above compounds that contains four germanium atoms per molecule.
When aqueous solutions of germanium(II) chloride and of iron(III) chloride are mixed, the following reaction occurs. GeCl2 + 2FeCl3 → 2FeCl2 + GeCl4 Explain why this is a redox reaction in terms of oxidation states. ___________________________________________________________ ___________________________________________________________ ___________________________________________________________
Miracle Learning Centre Answer to Chemistry Tuition Question on Bonding. (O Level / IP Chemistry) 1a) hard; unable to conduct electricity; b) in graphite, atoms are arranged in layers consisting of hexagonal rings; in diamond(germanium), atoms are arranged in tetrahedral shape; c) diagram of 1Ge and 4Cl; 4 shared pairs; d) i) GenH2n+2; ii) H H H H I I I I H – Ge – Ge – Ge - Ge - H I I I I H H H H e) The oxidation state of germanium changes from +2 to +4. Increase in oxidation state, thus oxidation. The oxidation state of iron changes from +3 to +2. Decrease in oxidation state thus reduction.
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.

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Chemistry Tuition Question on Organic Chemistry. (O Level / IP Chemistry)
1. Propanoic acid, C2H5CO2H, is a weak acid.
(a) Explain what is meant by the term weak acid.
(b) Propanoic acid reacts with sodium carbonate. Write the equation for this reaction.
(c) Magnesium reacts with propanoic acid to form magnesium propanoate and hydrogen.
Mg + 2C2H5CO2H  (C2H5CO2)2Mg + H2
A student added 4.80 g of magnesium to 30.0 g of propanoic acid.
(i) Which one of these reactants, magnesium or propanoic acid, is in excess? Explain your answer.
(ii) Calculate both the number of moles of hydrogen and the volume of hydrogen formed at r.t.p.
(d) Terylene has the simplified structure shown.
(i) State the functional groups on the monomers used to make Terylene.
(ii) State the type of polymerisation that occurs when Terylene is made.
State one large scale use of Terylene.
Many problems are caused by the disposal of plastics.
Describe one method of disposal of a plastic and a problem caused by this method.
Miracle Learning Centre Answer to Chemistry Tuition Question on Organic Chemistry. (O Level / IP Chemistry)
6. (a) acid which is only slightly or partly ionised/partly dissociated/not fully ionized .
(b) 2C2H5CO2H + Na2CO3 → 2C2H5CO2Na + CO2 + H2O
(c) (i) 24g of magnesium will need 2 x 74 g of propanoic acid to react so 4.8g magnesium requires 29.6g acid , so acid (30g) in excess OR
74g of propanoic acid will need ½ x 24g of Mg to react so 30g of acid requires 4.86g Mg so acid in excess (as only 4.8g Mg used) OR mol Mg = 4.8/24 = 0.2 mol acid = 30/74 = 0.405(4)/0.41 mol; 2x moles of acid required to 1 mole Mg Mg = 0.4 x 74 = 29.6g compared with 30 g acid OR 0.405/2 moles = 0.2027/0.203 moles acid compared with 0.2 moles Mg (Any two ) (ii) 0.2 mol H2 0.2 x 24 = 4.8 dm3 (d) (i) alcohols and carboxylic acids are monomers (both required) (ii) condensation (iii) clothing/named clothing/sails/conveyor or fan belts. (e) • take up landfill space because does not (bio)degrade. • incineration/burning – harmful substances/harmful fumes/harmful gases produced • recycling – difficult to sort out different polymers 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.