Question Library

(a)(i) Gasoline (ii) Diesel (iii) Kerosine (iv) Wax (any two) (b)(i) C\(_n\)H\(_{2n + 1}\)OH (ii) Oxidation (iii) 2CH\(_3\)COOH + Na\(_2\)CO\(_3\) ---> 2CH\(_3\) COONa + CO\(_2\) + H\(_2\)O.

(a) Gay - Lussac Law of combining volumes states that when gases react, they do so in volumes which are in simple ratios to one another and to the volume of the product, if gaseous, provided that the temperature and pressure remain constant. (b) 2H\(_2\) + O\(_2\) -> 2H\(_2\)O. According to the equation, 2 volume of H\(_2\) requires 1 volume of oxygen. 50cm\(^3\) of H\(_2\) requires 25cm\(^3\) of oxygen, volume of oxygen available = 30cm\(^3\), volume of unused oxygen 30 - 25 = 5cm\(^3\).

(a)(i) It reacts with ammonia (ii) It is a powerful bleaching agent (iii) It combines with water to form HOCI and HCI acids (b)(i) Displacement reaction (ii) Redox reaction.

(a)(i) Sodium(Na) (ii) copper (Cu) (iii) magnesium (Mg) (b)(i) J is lead (Pb) (ii) Reduction.

(a)(i) Entropy is defined as the degree of disorderliness or randomness in a chemical system. (ii) Endothermic (b)(i) Energy barrier (ii) Activation energy.

(a)(i) Ammonium chloride and calcium hydroxide (ii) - Ammonia is an alkaline gas, it turns red litmus paper blue. - It is less dense than air. - A colourless gas with characteristic choking smell. (iii) Haber process - is the direct combination of hydrogen and nitrogen in volume ratio 3:1 respectively. The mixture is passed over a finely divided iron catalyst at a temperature of about 500^\circC and a pressure of 250 atmosphere yield ammonia. It is a reversible reaction. 3H\(_2\) + N\(_2\) \(\to\) 2NH\(_3\) (b) (i)2NH + 3CuO \(\to\) 3Cu + 3H\(_2\)O + N\(_2\) (ii) (NH\(_4\))\(_2\)CO\(_3\) \(\to\) 2NH\(_3\) + CO\(_2\) + H\(_2\)O (c)(i) catalytic oxidation of ammonia (ii) dilute trioxonitrate (v) acid does not generally give off hydrogen because any hydrogen formed is immediately oxidized by more of the acis to form water (d)(i) with bases NaOH + HNO\(_3\) \(\to\) CO\(_2\) + 2H\(_2\)O + 4NO\(_2\)

(a)(i) - Neutralization of a base by an acid - Direct combination of elements (ii) Thermometer, water bath and stirrer (b)(i) The solubility of K at 50\(^o\) equal to 0.58mol/dm\(^3\) (ii) The solubility of L equals to 1.0mol/dm\(^{-3}\) at 57\(^o\)C (iii) K is more soluble than L over the temperature range of 0\(^o\) to 31.5\(^o\)C (iv) Molar mass of L = 101g 3.4gm of L per 250cm\(^3\) \(\to\) 3.4 \(\to\) 250X \(\to\) 1000X = \(\frac{1000}{250}\) x 3.4 = 13.6g/dm\(^3\) At 20\(^o\)C the molar conc. of L = 0.34 The solubility 101 x 0.34 = 34.34g/dm\(^3\) at 20\(^o\)C. Since the concentration/solubility of 13.6g/dm\(^3\) is lower than the required solubility of 34.34g/dm\(^3\) at 20\(^o\)C, it is therefore not saturated ie. unsaturated

(a)(i) Cracking is the conservation of surplus supplies of less desirable fraction such as kerosine and gas oil into petrol (ii) C\(_2\)H\(_5\)OH C\(_2\)H\(_4\) (iii) When ethane and ethene are separately passed through water (a)(i) polysaccharide (ii) Fractional distillation (iii) sodium ethoxide (iv) 2-chloro ethanol (c)(i) Benzene produces more soot than ethene due to the high carbon of the former (ii) Because of higher molecular weight and higher carbon content in ethanoic acid than methanoic acid (iii) The sodium chloride used during the manufacture of soap is to decrease the solubility of the soap so that it separates out as hard cake (d)(i) ethyne - in synthesis to neoprene rubber (ii) coal - is used mainly as a fuel (iii) carbon black - used in manufacturing tyre

(a)(i) - They formed coloured ions in solution - They exhibit variable oxidation - They exhibit very high catalytic activity (ii) Quantity of electricity (Q) = current x time Q = 1.8 x 12.5 x 60 = 1350 coulombs M\(^{2+}\) + 2e\(^-\) M; 2 x 96500 will liberate one mole of the metal but 1350 liberatrate 0.45 2 x 96500 \(\to\) X; X = \(\frac{2 \times 96500}{1350}\) x 0.45 = 64.33 The relative molecular mass of m is 64.33 (iii) copper - plated iron corrodes easily when scratched because the iron is exposed to moisture, which readily reacts with iron to form iron(iii) oxide (rust). Copper has high resistance to corrosion but iron does not (b)(i) The law of definite proportion states that all pure sample of a particular chemical compound contain similar elements combined in the same proportion by mass (ii) - weigh the sample of copper (II) oxide in boat - place the boat inside a hard glass tube - Heat the sample strongly while passing a stream of dry hydrogen gas through the glass tube - Remove the flame, but continue to pass hydrogen gas as the sample cools down - Weigh the residue, the difference in mass is the quantity of oxygen in the sample (b)(iii) 2Cu(NO\(_3\))\(2\) \(\to\) 2CuO + O\(_2\) + 4NO\(_2\)

(a)(i) Bomb calorimeter (ii) Hoffman voltameter. (b)(i) Solubility in water, glucose is soluble in water while cellulose is not soluble in water (ii) Glucose is a strong reducing agent, it reduces Fehling's solution to red precipitate of copper (I) oxide on boiling. Cellulose does not reduce Fehling's solution (c)(i) (c)(ii) NH\(_4\)Cl, and iodine (d)(i) Pb(NO\(_3\))\(_2\) (ii) The brown fumes (NO\(_2\)) turns damp blue litmus paper red. (iii) It is not advisable to collect nitrogen by displacement of air because it has about the same density as air.

Test Observation Inference (a)(i) C + water + litmus Soluble in water to give a colourless solution which turns red litmus blue Basic solution (ii) C + HCl\(_{(aq)}\) Effervescence occurs colourless and odourless gas evolved gas which turns lime water milky The gas is CO\(_2\) from CO\(_3^{2+}\) (b)(i) D + NaOH\(_{(aq)}\) + Heat Colourless gas evolved with characteristic chocking smell which turns litmus blue and form white fumes with conc. HCl acid stopper/Vapour Gas is NH\(_3\) NH\(_4^+\) present (ii) D + water + BaCl\(_{2(aq)}\) and HCl It is soluble in water, white ppt. formed, ppt. dissolved forming a colourless soln. Colourless gas with irritating smell evolved; the gas turned the colour of acidified K\(_2\)Cr\(_2\)O\(_7\) or soln. from orange to green SO\(_3^{2-}\), SO\(_4^{2-}\) or CO\(^{2-}_3\) or S\(^{2-}\) present the gas is SO\(_2\) from SO\(_4^{2-}\)

Burette readings Rough 1st 3rd 3rd Final burette reading (cm\(^3\)) 23.50 33.00 23.00 28.00 Initial burette reading (cm\(^3\)) 0.00 10.00 0.00 5.00 Initial burette reading (cm\(^3\)) 23.50 23.00 23.00 23.00 (a) Average volume of the acid(titre) = \(\frac{23.00 + 23.00 + 23.00}{3}\) = 23.00 cm\(^3\) (b) A is 0.050 mol dm\(^{-3}\) of HCl; B is 0.25 mol dm\(^{-3}\) of XCO\(_3\) Let the mole ratio of the acid to the triocarbonate (IV) be M From \(\frac{\text{concentration of A(C\(_A\)) x volume of (V\(_A\))}}{\text{concentration of B(C\(_B\)) x volume of (B)(V\(_B\))}}\) \(\frac{0.050 \times 23.00}{0.025 \times 25.00}\) = m m = 1.84 Since m = \(\frac{A}{B}\) A : B = 1.84 : 1 A : B approximately 2 : 1 expressed in a whole number ratio (c) Molar mass of XCO\(_3\) = 160g (given); concentration = 7.2g/dm\(^3\) (hydrated trioxocarbonate) (i) concentration of anhydrous salt = mole concentration x molar mass 0.025 x 106 = 2.65 m/dm\(^3\) (ii) percentage of water of crystallisation = \(\frac{7.2 - 2.65}{7.2} \times \frac{100}{1}\)% = \(\frac{4.55}{7.2}\) x 100% = 63.19%

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

(a)(i) An infant recognises only comfort or discomfort (ii) An infant percieves his environment as a strange world. (b) He first learns that his parents are people who respond to his needs. (c)(i) The parents learn the developing traits of the child (ii) The parents learn what the child may become in future (d) A responsible parent sometimes has to take unpleasant action/subject the child to unpleasant experiences.

SOW WIND AND REAP WHIRLWIND Once upon a time, there lived a man called Chief Olowolayemo. He was a rich man who was highly respected in his town. Chief Olowolayemo had two wives. The name of the first wife was Phebe Ademosun while the second and younger wife was Ebun. Chief Olowolayemo married the first wife when he was poor. Phebe was a loving wife, who loved her husband and struggled very hard with her husband to acqire money. She had seven children for Chief Olowolayemo, six of whom were girls and the last was a boy. It was because it took her a long time to have a male child that her husband decided to marry Ebun, his second wife. Ebun was the daughter of the great herbalist in the town of Ilugun. Ebun's father was famous for bad medicines and charms. When she became Chief Olowolayemo's wife. Ebun was about eighteen years old while the first wife was twenty-nine. Phebe, the chiefs first wife accepted Ebun as her wife and always took care of her when she newly came into the family. At the time the Chief married Ebun. Phebe had five female children. The first wife. despite the fact that her husband was fed up with her after having five female children. was a pleasant woman who embraced Ebun and extended hands of fellowship to her. Before too long. Ebun became pregnant and had her first child who happened to be a male. Chief Olowolayemo was very happy after waiting for so long to have a male child The first wife in her normal pleasant character regarded the arrival of the male child as an open way for her to have her own. Thus. she named the child Adesina. Adesina grew up to love his father's eldest wife because the woman showed no inhibition in loving him. To cut the long story short, Ebun had three boys for her husband and the eldest wife had six female and one male children. Chief Olowolayemo was trying his best to share his love among the two wives. The first wife in her characteristic manner showed love and affection for Ebun. the junior wife. The children were growing up in the same family. They were attending schools. The children of the first wife were more brilliant in the school than the children of the second wife. The most brilliant of all the children was the last male child of the first wife called Oluomo. This always annoyed the second wife who became unhappy with her three children She always scolded them and made remarks that their younger brother was acknowledged to be more brilliant than they. As a result of this she decided to complain to her father She visited her father and when she told him her fears of the effect that Oluomo would be more popular than her three male children. she demanded that her father should give her poison to kill Oluomo. She collected the poison and headed home. When she got home she decided to poison Oluomo's food The second week after this it was her turn to prepare food for the whole family. She prepared a good meal and poisoned Oluomo's food which she kept on a table where he could see it to eat. When the children closed from school, Adesina. Ebun's first child rushed home ahead of others. On getting home, he met nobody in the house and he was hungry. He started searching the kitchen for food. The first plate of food he saw on the table was the food his mother had poisoned and meant for Oluomo He took the food and ate hurriedly. Soon after eating, he started feeling stomach-ache and before long. he started rolling on the floor. writhing in pains. As this was happening, the other children came into the house. They were crying for help when the two wives and Chief Olowolayemo came in. The wicked woman rushed in crying while others were trying to rush the boy to the hospital. Ebun could no longer contain the situation and she began to cry out: "I have killed my son I don't know it will end like this '. When they heard this, the sympathisers who gathered forced her to explain. After listening to her dastardly story, her husband sent her packing. She begged for pity but her husband said: "Get away wicked wife, you reap what you sow"