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No expanded working has been attached for this question yet. The verified answer is Option B.

No expanded working has been attached for this question yet. The verified answer is Option D.

(a) - NaOH, filtration apparatus, source of heat, standard flask. (ii) Effervescence occurs, CO\(_2\) from trioxocarbonate (IV) is given off. (b)(i) To the solution of the substance, add potassium hexacyanoferrate (II) K\(_2\)Fe(CN)\(_6\) solution. A white ppt. confirms the presence of zinc ions or to the solution of the substance add few drops of ammonia solution, then add ammonium chloride solution. A white precipitate confirms the presence of aluminum ions (ii) (I) CaCO\(_3\) (II) Aqueous ammonia (III) Conc. H\(_2\)SO\(_4\) (c)(i) FeSO\(_4\) easily undergo oxidation when left for some time. (ii) The first jar contains a mixture of hydrogen and air.

(a)(i) Characteristic properties of electrovalent compounds. - They do not contain molecules - They dissolve in water to form electrolyte - They have high melting or boiling point - They are mostly inorganic compounds (ii) Alpha particles: They are positively charged - They have low penetrating power - They exert a very powerful ionizing effect upon any gas through which they pass. (iii) Catalysts : Catalysts remain unchanged in chemical nature and in mass at the end of a reaction. - Catalysts alter the rate of a chemical reaction - They are specific in action - Catalysts cannot initiate or start a reaction - They have no effect on the equilibrium of a reversible reaction. (b)(i) \(_{14}\)Si - 1S\(^2\)2S\(^2\) 2P\(^6\)3S\(^2\)3P\(^2\). Silicon belongs to group four in the periodic table. (ii) Bond between silicon and oxygen is covalent. (iii) 1 mole of silicon has a mass of 28 and 6.02 x 10\(^{23}\) atom, in 5.72 x 10\(^{-3}\) g. = \(\frac{5.72 \times 10^{-3}}{28}\) x 6.02 x 10\(^{23}\) = 1.2298 x 10\(^{20}\). (c)(i) X is a good reducing agent because it will react with water to liberate hydrogen. (ii) X is best stored under oil. (iii) X will react with cold water to liberate hydrogen gas. It is a violent reaction. (iv) X\(_2\)O + 2HCI \(\to\) 2XCI + H\(_2\)O. (v) The likely colour of the salt of X is white.

(a)(i) Acid anhydride means acid without water. e.g. SO\(_2\), CO\(_2\), etc. (ii) HCI react with metals more electropositive than hydrogen to liberate hydrogen gas. -HCI reacts with bases or alkali to produce salt and water only. -They react with trioxocarbonate (IV) and hydrogen trioxocarbonate (IV) to literate carbon (IV) oxide. (b)(i) H\(_2\)SO\(_4\) can form a neutral salt and also an acid salt while NHO\(_3\) can only form a neutral salt. (ii) Both copper and iron have low standard electrode potential and only iron reacts with the dilute acid because it is more active than copper (iii) The zinc dust has larger area of contact for the reaction to take place unlike the zinc granules. (c)(i) Activation energy in the combined energy which the reactant particles must have in order to react or for a reaction to occur. (iii) The heat of reaction of the mineral acids with sodium hydroxide is constant because the only change that actually occurs during the reaction is the formation of water molecule which has an approximately constant value of- 57.4 kJmol\(^{-1}\) (d)(i) Q\(_{(s)}\) has higher entrophy because the molecules of Q\(_{(s)}\) are free to move than that of Q\(_{(s)}\) (ii) Decrease in temperature will favour the reverse reaction.

(a)(i) (ii) At the anode Cu\(_{(s)}\) - 2e\(^-\) -> Cu\(^{2+}\)\(_{(ag)}\); At the cathode Cu\(^{2+}\) + 2e \(\to\) Cu\(_{(s)}\) (iii) Daniell cell is an electrochemical cell because chemical energy (from the reaction between the electrodes and the solution) is converted into electrical energy. (iv) The function of MnO\(_2\) in the Leclanche cell Pure copper plate is to serve as depolarizer that is preventing the impure copper (cathode) hydrogen gas from adhering to the anode. (b)(i) In MnO\(^-_4\) - + 8H\(^+\) + xe\(^-\) \(\to\) Mn\(^{2+}\) + yH\(_2\)O ; x = 5, y = 4 (ii) The oxidation of Mn in MnO\(^-_4\) is +7. (c)(i) - Position of the ions in the electro-chemical series -Concentration of the ions in the electrolyte -Nature of the electrode. (ii) Faraday's second law oxosulphate of electrolysis states that when the same quantity of electricity is passed through different electrolytes the relative number of moles of the elements discharged are inversely proportional to the charge on the ions of each of the elements respectively. (iii) AgNO\(_3\) and CuSO\(_4\) ; Ag\(^+\) + e\(^-\) -> Ag\(_{(s)}\) ; Cu\(^{2+}\) + 2e\(^-\) -> Cu\(_{(s)}\) 96500C will liberate 108; It liberated 0.780 It = \(\frac{0.780}{108}\) x 96500C = 696.9C (d)(i) 2 x 96500 C will liberate 63.50 ; 696.9C will liberate = \(\frac{696.9}{2 \times 96500}\) x 63.50 = 0.2293g. (ii) The quantity of electricity = 696.2 C. but Q = It ; 0.200 x t = 696.9 t = \(\frac{696.9}{0.200}\) = 3484.5s; = 58.075 mins.

(a)(i) -All members of a homologous series share a general molecular formula. -Each successive member in a series differs in its molecular formula by the addition of a - CH2 -. -All members show similar chemical properties -All members can usually be prepared by using the same general methods. (ii) The second member of the alkyne is propyne with formula C\(_3\)H\(_4\). The structure is (iii) C\(_2\)H\(_6\) + 4\(_2\) -> 2CO\(_2\) + 4H\(_2\)O (b)(i) Dehydration (ii) Esterification (iii) Substitution (iv) Reduction (v) Oxidation (c)(i) 2 - methylpropanoic acid (ii) Molecular formula C\(_4\)H\(_8\)O\(_2\) = CH\(_3\) CH(CH\(_3\)) COOH. Empirical formula = C\(_2\)H\(_4\)O (iii) Sodium, 2 - methyl propanoate and water. (CH\(_3\)CH(CH\(_3\))COONa + H\(_2\)O) (iv) The boiling point of 2 - methyl propanoic acid will be higher than that of the corresponding alkane because it is a liquid, while the corresponding alkane is a gas. (d)(i) Y is hydrogen. (ii) The activated charcoal is to bleach off the natural colour of the oil. (iii) Finely divided nickel. (iv) The product are soap and propane - 1, 2, 3 - triol.

(a)(i) Fused calcium chloride and concentrated tetraoxosulphate (VI) acid. (ii) Ca(OH)\(_2\), NaOH. (iii) Hydrogen and carbon (II) oxide (iv) Zn metals, zinc trioxocarbonate (IV), zinc oxides. (b)(i) Soft solder for welding and plumbing and type metal for printing. (ii) a black precipitate of PbS\(_{(s)}\) is deposited (iii)(i) Polymorphism (ii) Transition temperature (c)(i) 2AgNO\(_{3(s)}\) --> 2Ag\(_{(s)}\) + O\(_2\) + 2N\(O_2\). Lustrous Brown white (ii) NH\(_4\)CO\(_3\) -> 2NH\(_3\) + CO\(_2\) + H\(_2\)O. (iii) Metal Name of main ore Method of extraction One major use Iron Iron Haematite Reaction process Constfuction of vehicles Aluminium Bauxite Electrolysis of molten oxide cables, paints, cooking utensils

(a) MgSO\(_4\) is prepared in the laboratory by the action of dilute H\(_2\)SO\(_4\) on MgO. On crystallisation the hepta hydrate crystals MgSO\(_4\). 7H\(_2\)O known as Epsom salt is obtained. MgO + H\(_2\)SO\(_4\) -> MgSO\(_4\) + H\(_2\)O. (b)(i) - Industrial effuents -.Human waste. -Human activities (ii) During boiling some molecules of water do break up into oxygen and hydrogen, the oxygen then combine with the atmospheric oxygen. (iii) Alum (a double salt) (c)(i) - It is a greenish yellow gas - It is moderately soluble in water - It is about 2.5 times denser than air -It can be liquefied under pressure - It is poisonous. (ii) 2 FeCl\(_2\) + Cl\(_2\) ----> 2FeCI\(_3\) (iii) Chlorine is preferred to sulphur (IV) oxide in the bleaching of cotton because the bleaching action of SO\(_2\) usually does not last since the bleached dye become re-oxidized by atmospheric oxygen to form the original coloured compound. This is not so with chlorine. (d) CaOCl\(_2\) + 2HCI -> CaCl\(_2\) + H\(_2\)O + Cl\(_2\) from the equation. (40 + 16 + 35.5 x 2)g CaOCl\(_2\) will produce 22400cm\(^3\) of Cl\(_2\) at s.t.p. 127g -> 22400cm\(^3\) at temp. = 273k and pressure = 1.01 x 10\(^5\) N/M\(^{-2}\); Volume of CaOCl\(_2\) at s.t.p. \(\frac{P_1 V_1}{T_1}\) = \(\frac{P_2V_2}{T_2}\) \(V_2 = \frac{P_1V_1T_2}{T_1P_2}\) = \(\frac{1.20 \times 10^5 \times 400 \times 273}{298 \times 1.01 \times 1.05}\) = 435.4cm\(^3\) 127g -> 22400dm\(^3\) ; y -> 435.4dm\(^3\) y mass or CaOCl\(_2\) = \(\frac{435.4}{22400}\) x 127 = 2.468g

No expanded working has been attached for this question yet. The verified answer is Option D.

Rough 1st Reading 2nd Reading 3rd Reading 3ed Reading Final volume 27.00 36.00 26.05 40.95 Initial volume 0.00 10.00 0.00 15.00 Volume A used 27.00 26.00 26.05 25.95 Volume pipette = 25cm\(^3\) Volume of A used = \(\frac{26.00 + 26.95 + 25.95}{3}\) = \(\frac{78.00}{3}\) = 26.00 cm\(^3\) Equation for reaction; HCL + KHCO\(_3\) \(\to\) KCl + CO\(_2\) (i) Let C\(_A\) represent the conc. of A = 0.100 mol sm\(^{-3}\) V\(_A\) volume of A = 26.00 cm\(^3\) C\(_B\) conc. of B = ? V\(_B\) volume of B = 25.00 cm\(^3\) \(_n\)A mole of A = 1 \(_n\)B mole of B = 1 from \(\frac{C_A \times V_B}{C_B \times V_B} = \frac{1}{1}\) = \(\frac{0.100 \times 26}{C_B \times 25} = \frac{1}{1}\) C\(_B\) = \(\frac{0.100 \times 26}{25}\) = 0.104 mol dm\(^{-3}\) (ii) Mass KHCO\(_3\) in mol/dm\(^3\) Molar mass of KHCO\(_3\) = 39 + 1 + 12 + 16 x 3 = 100 Mass = 0.104 x 100 = 10.4g/dm\(^3\) (iii) Percentage by mass of KHCO\(_3\) in the mixture = \(\frac{15.0 - 10.4}{15} \times \frac{100}{1}\) % = \(\frac{4.6}{15} \times \frac{100}{1}\)% = 30.7% (iv) Mass of NaCl in the mixture = 15.0 - 10.4 = 4.6g

Test Observation Inference (a) (i) C + water and tested with litmus C is soluble in water, no action on litmus Soluble, carbohydrate(Sugar) (ii) C + water + Fehling's solution Brick red precipitate was observed Reducing sugar glucose is suspected (b)(i) D + strong heat A black residue was obtained and a reddish-brown gas evolved NO\(_2\) from NO\(_3^-\) CUO is suspected (as residue) (ii) D + water A light blue solution was obtained. D is a soluble in water Cu\(^{2+}\) is suspected (iii) D + NH\(_4\)OH A blue precipitate was observed which dissolved in excess alkali to give a blue solution Cu\(^{2+}\) is present Conclusion - C is a reducing sugar (glucose) and is a salt which is Cu(NO\(_3\))\(_2\)

(a) - NaOH, filtration apparatus, source of heat, standard flask. (ii) Effervescence occurs, CO\(_2\) from trioxocarbonate (IV) is given off. (b)(i) To the solution of the substance, add potassium hexacyanoferrate (II) K\(_2\)Fe(CN)\(_6\) solution. A white ppt. confirms the presence of zinc ions or to the solution of the substance add few drops of ammonia solution, then add ammonium chloride solution. A white precipitate confirms the presence of aluminum ions (ii) (I) CaCO\(_3\) (II) Aqueous ammonia (III) Conc. H\(_2\)SO\(_4\) (c)(i) FeSO\(_4\) easily undergo oxidation when left for some time. (ii) The first jar contains a mixture of hydrogen and air.

The passage describes how the rise of motor vehicles (cars, lorries, and motorcycles) led to changes in road transport, such as the adaptation of road surfaces through tar-spraying and efforts to widen and straighten roads. Although challenges remained, these adjustments indicate an overall improvement in road transport systems.

The expression "unless mechanically minded" refers to coachmen and grooms who would struggle to adapt to the new technology of motor vehicles. In other words, only those are can adapt to new technology would be able to continue making a living, as the rise of motor vehicles was making traditional roles like that of coachmen and grooms obsolete.