Chemistry, 1985, JAMB Exam, Exam, Paper 1 | Objectives

Paper Info

Year :

1985

Title :

Chemistry

Exam :

JAMB Exam

Paper 1 | Objectives

41 - 48 of 48 Questions

#	Question	Ans
41.	Given that the molecular mass of iron is 56 and that of oxygen is 16, how many moles of iron(iii)oxide will be contained in 1kg of the compound? A. 25.0 moles B. 12.5 moless C. 6.25 moles D. 3.125 moles E. 0.625 moles Show Content Detailed Solution Fe₂O₃ = 56 x 2 + 48 = 160 = 1 moles 1000gm will contain \(\frac{1000}{160}\) = 6.25 moles	C
42.	3.0g of a mixture of potassium carbonate and potassium chloride were dissolved in a 25cm³ of this solution required required 40.00cm₃ of 0.1M HCl for neutralization. What is the percentage by weight of K₂CO₃ in the mixture. (K = 39, O = 16, C = 12) A. 60 B. 72 C. 82 D. 89 E. 92	E
43.	Some properties of chemical substances are mentioned below... i. sour taste ii. slippery touch iii. yields alkaline gas with ammonium salt iv. has pH less than 7 v. turns phenolphthalein pink. Which of the above are NOT typical properties of alkalis? A. i, iv and v B. iv and v C. i and iv D. ii and v E. ii, iii and iv	C
44.	A certain volume of gas at 298k is heated such that its volume and pressure are now four times the original values. What is the new temperature? A. 18.6k B. 100.0k C. 298.0k D. 1192.0k E. 4768.0k Show Content Detailed Solution \(\frac{P_1V_1}{T_1} = \frac{4P_1 \times 4V_1}{T_2}\) i.e \(\frac{P_1V_1}{298} = \frac{4P_1 \times 4V_1}{T_2}\) T² = \(\frac{298 \times 4P_1 \times 4V_1}{P_1V_1}\) = 298 + 16 = 4768.0k	E
45.	Hydrogen is not liberated when trioxonitrate(v)acid reacts with zinc because A. zinx is not rendered passive by acid B. hydrogen produced is oxidized to water C. oxides of nitrogen are produced D. all nitrates are soluble in water E. trioxonitrate(v)acid is a strong acid Show Content Detailed Solution When metals react with nitric acid, hydrogen gas is liberated. Nitric acid is a very strong oxidizing agent. So , it oxidizes the hydrogen gas formed during the reaction to form water and an oxide of nitrogen. \(Zn+4HNO_{3} \to Zn(NO_{3})_{2} + 2NO_{2} + 2H_{2}O\)	B
46.	The boiling point of water, ethanol, toluene and butan-2-ol are 373.0k, 351.3k, 383.6k and 372.5k respectively. Which liquid has the highest vapour pressure at 323.0k? A. water B. toluene C. ethanol D. butan-2-ol E. none	C
47.	In what respect will two dry samples of nitrogen gas differ from each other if sample 1 is prepared by completely removing CO₂ and O₂ from air, and sample 2 is prepared by passing purified nitrogen(i)oxide over heated copper? sample 1 is A. purer than sample 2 B. slightly denser than sample 2 C. in all respects the same as sample 2 D. colourless but sample 2 has a light brown colour E. slightly less reactive than sample 2	B
48.	Copper sulphate solution is electolysed using platinum electrodes A. current of 0.193 amperes is passed for 2hrs. How many grams of copper are deposited? (cu = 63.5, F = 96500 coulombs) A. 0.457g B. 0.500g C. 0.882g D. 0.914g E. 1.00g Show Content Detailed Solution Time = 2hrs 120mm = 120 x 60secs current = 0.193amps Quantity of electricity = 120 x 0.193 = 60 x 23.16 96,500 deposits 63.5 gms of Cu 60 x 23.2 will deposit \(\frac{63.5 \times 60 \times 23.2}{96500}\) = 0.457	A

41.	Given that the molecular mass of iron is 56 and that of oxygen is 16, how many moles of iron(iii)oxide will be contained in 1kg of the compound? A. 25.0 moles B. 12.5 moless C. 6.25 moles D. 3.125 moles E. 0.625 moles Show Content Detailed Solution Fe₂O₃ = 56 x 2 + 48 = 160 = 1 moles 1000gm will contain \(\frac{1000}{160}\) = 6.25 moles	C
42.	3.0g of a mixture of potassium carbonate and potassium chloride were dissolved in a 25cm³ of this solution required required 40.00cm₃ of 0.1M HCl for neutralization. What is the percentage by weight of K₂CO₃ in the mixture. (K = 39, O = 16, C = 12) A. 60 B. 72 C. 82 D. 89 E. 92	E
43.	Some properties of chemical substances are mentioned below... i. sour taste ii. slippery touch iii. yields alkaline gas with ammonium salt iv. has pH less than 7 v. turns phenolphthalein pink. Which of the above are NOT typical properties of alkalis? A. i, iv and v B. iv and v C. i and iv D. ii and v E. ii, iii and iv	C
44.	A certain volume of gas at 298k is heated such that its volume and pressure are now four times the original values. What is the new temperature? A. 18.6k B. 100.0k C. 298.0k D. 1192.0k E. 4768.0k Show Content Detailed Solution \(\frac{P_1V_1}{T_1} = \frac{4P_1 \times 4V_1}{T_2}\) i.e \(\frac{P_1V_1}{298} = \frac{4P_1 \times 4V_1}{T_2}\) T² = \(\frac{298 \times 4P_1 \times 4V_1}{P_1V_1}\) = 298 + 16 = 4768.0k	E

45.	Hydrogen is not liberated when trioxonitrate(v)acid reacts with zinc because A. zinx is not rendered passive by acid B. hydrogen produced is oxidized to water C. oxides of nitrogen are produced D. all nitrates are soluble in water E. trioxonitrate(v)acid is a strong acid Show Content Detailed Solution When metals react with nitric acid, hydrogen gas is liberated. Nitric acid is a very strong oxidizing agent. So , it oxidizes the hydrogen gas formed during the reaction to form water and an oxide of nitrogen. \(Zn+4HNO_{3} \to Zn(NO_{3})_{2} + 2NO_{2} + 2H_{2}O\)	B
46.	The boiling point of water, ethanol, toluene and butan-2-ol are 373.0k, 351.3k, 383.6k and 372.5k respectively. Which liquid has the highest vapour pressure at 323.0k? A. water B. toluene C. ethanol D. butan-2-ol E. none	C
47.	In what respect will two dry samples of nitrogen gas differ from each other if sample 1 is prepared by completely removing CO₂ and O₂ from air, and sample 2 is prepared by passing purified nitrogen(i)oxide over heated copper? sample 1 is A. purer than sample 2 B. slightly denser than sample 2 C. in all respects the same as sample 2 D. colourless but sample 2 has a light brown colour E. slightly less reactive than sample 2	B
48.	Copper sulphate solution is electolysed using platinum electrodes A. current of 0.193 amperes is passed for 2hrs. How many grams of copper are deposited? (cu = 63.5, F = 96500 coulombs) A. 0.457g B. 0.500g C. 0.882g D. 0.914g E. 1.00g Show Content Detailed Solution Time = 2hrs 120mm = 120 x 60secs current = 0.193amps Quantity of electricity = 120 x 0.193 = 60 x 23.16 96,500 deposits 63.5 gms of Cu 60 x 23.2 will deposit \(\frac{63.5 \times 60 \times 23.2}{96500}\) = 0.457	A