Chemistry, 1978, JAMB Exam, Exam, Paper 1 | Objectives

Paper Info

Year :

1978

Title :

Chemistry

Exam :

JAMB Exam

Paper 1 | Objectives

11 - 20 of 48 Questions

#	Question	Ans
11.	When large hydrocarbon molecules are heated at high temperature in the presence of a catalyst to give smaller molecules, the process is known as A. disintegration B. polymerization C. cracking D. degradation E. distillation	C
12.	The pH of four solutions W, X, Y, Z are 4, 6, 8, 10 respectively, therefore A. none of these solutions is acidic B. the pH of Y is made more acidic by addition of distilled water C. Z is the most acidic solution D. W is the most acidic solution E. X is neutral Show Content Detailed Solution W is the most acidic solution since 4 < 6 < 8 < 10. The lower the value on the pH scale, the more acidic a solution.	D
13.	When each of the nitrates of Potassium, Magnesium and iron is heated, A. all the nitrates decompose to their oxides B. the nitrate of magnesium gives the nitrite and oxygen C. the nitrates of iron magnesium and iron give the oxides D. the nitrate of iron gives the nitrite and oxygen E. the nitrate of the magnesium is not decomposed	C
14.	Which of the following metals cannot replace hydrogen from water or steam? A. Sodium B. Magnesium C. Iron D. Calcium E. Copper	E
15.	A sample of hard water contains some calcium sulphate and calcium hydrogen carbonate. The total hardness may therefore be removed by A. boiling the water B. adding excess calcium hydroxide C. adding a calculated amount of calcium hydroxide D. adding sodium carbonate E. adding magnesium hydroxide	D
16.	During the electrolysis of copper II sulphate between platinum electrodes, if litmus solution is added to the anode compartment, A. the litmus turns blue but no gas is evolved B. the litmus turns blue and oxygen is evolved C. the litmus turns blue and hydrogen is evolved D. the litmus turns red and oxygen is evolved E. the litmus turns red and then becomes colourless	D
17.	The reaction between an organic acid and an alcohol in the presence of an acid catalyst is known as; A. saponification B. dehydration C. esterification D. hydrolysis E. hydration	C
18.	The IUPAC names of the compounds CH3COOH and CH2=CH2 are respectively; A. acetic acid and ethene B. methanoic acid and ethene C. methanoic acid and ethylene D. ethanol and ethene E. acetic acid and ethylene Show Content Detailed Solution The IUPAC id for \(CH_{3}COOH\) is Acetic acid, while for \(C_{2}H_{4}\) is ethene.	A
19.	If 30cm³ of oxygen diffuses through a porous pot in 7 seconds, how long will it take 60cm³ of chlorine to diffuse through the same pot, if the vapour densities of oxygen and chlorine are 16 and 36 respectively? A. 9.3 sec B. 14 sec C. 21 sec D. 28 sec E. 30.3 sec Show Content Detailed Solution The rate of diffusion of a gas is proportional to the square root of the density. 16 and 7 secs 36 or 6 will be proportional to 7/16 x 6 7/4 x 6 But volume of chlorine is twice that of oxygen. The rate of escape of chlorine is 2/1 x 7/4 x 6/1 = 7 x 3; = 21 sec	C
20.	Brass and bronze are both metallic alloys. Which of the following constituents is common to both alloys? A. Tin B. Zinc C. Copper D. Lead E. Aluminium	C

11.	When large hydrocarbon molecules are heated at high temperature in the presence of a catalyst to give smaller molecules, the process is known as A. disintegration B. polymerization C. cracking D. degradation E. distillation	C
12.	The pH of four solutions W, X, Y, Z are 4, 6, 8, 10 respectively, therefore A. none of these solutions is acidic B. the pH of Y is made more acidic by addition of distilled water C. Z is the most acidic solution D. W is the most acidic solution E. X is neutral Show Content Detailed Solution W is the most acidic solution since 4 < 6 < 8 < 10. The lower the value on the pH scale, the more acidic a solution.	D
13.	When each of the nitrates of Potassium, Magnesium and iron is heated, A. all the nitrates decompose to their oxides B. the nitrate of magnesium gives the nitrite and oxygen C. the nitrates of iron magnesium and iron give the oxides D. the nitrate of iron gives the nitrite and oxygen E. the nitrate of the magnesium is not decomposed	C
14.	Which of the following metals cannot replace hydrogen from water or steam? A. Sodium B. Magnesium C. Iron D. Calcium E. Copper	E
15.	A sample of hard water contains some calcium sulphate and calcium hydrogen carbonate. The total hardness may therefore be removed by A. boiling the water B. adding excess calcium hydroxide C. adding a calculated amount of calcium hydroxide D. adding sodium carbonate E. adding magnesium hydroxide	D

16.	During the electrolysis of copper II sulphate between platinum electrodes, if litmus solution is added to the anode compartment, A. the litmus turns blue but no gas is evolved B. the litmus turns blue and oxygen is evolved C. the litmus turns blue and hydrogen is evolved D. the litmus turns red and oxygen is evolved E. the litmus turns red and then becomes colourless	D
17.	The reaction between an organic acid and an alcohol in the presence of an acid catalyst is known as; A. saponification B. dehydration C. esterification D. hydrolysis E. hydration	C
18.	The IUPAC names of the compounds CH3COOH and CH2=CH2 are respectively; A. acetic acid and ethene B. methanoic acid and ethene C. methanoic acid and ethylene D. ethanol and ethene E. acetic acid and ethylene Show Content Detailed Solution The IUPAC id for \(CH_{3}COOH\) is Acetic acid, while for \(C_{2}H_{4}\) is ethene.	A
19.	If 30cm³ of oxygen diffuses through a porous pot in 7 seconds, how long will it take 60cm³ of chlorine to diffuse through the same pot, if the vapour densities of oxygen and chlorine are 16 and 36 respectively? A. 9.3 sec B. 14 sec C. 21 sec D. 28 sec E. 30.3 sec Show Content Detailed Solution The rate of diffusion of a gas is proportional to the square root of the density. 16 and 7 secs 36 or 6 will be proportional to 7/16 x 6 7/4 x 6 But volume of chlorine is twice that of oxygen. The rate of escape of chlorine is 2/1 x 7/4 x 6/1 = 7 x 3; = 21 sec	C
20.	Brass and bronze are both metallic alloys. Which of the following constituents is common to both alloys? A. Tin B. Zinc C. Copper D. Lead E. Aluminium	C