JAMB Chemistry 1997 Past Questions and Answers

Chemistry JAMB 1997 Q1 ✓ Answer: B

35 cm3 of hydrogen was sparked with 12cm3 of oxygen at 110o C and 760 mm Hg to produce steam. What percentage of the total volume gas left after the reaction is hydrogen

A

11%

B

31%

C

35%

D

69%

Chemistry JAMB 1997 Q2 ✓ Answer: D

2.85 g of an oxide of copper gave 2.52g of copper on reduction and 1.90 g of another oxide gave 1.52 g of copper on reduction. The data above illustrates the law of

A

constant composition

B

conservation of mass

C

reciprocal proportions

D

multiple proportions. [PAGE 47] Use the graph below to answer question 3 and 4 A sample, X, solid at room temperature, was melted, heated to a temprature of 358 K and allowed to cool as shown in OPQR.

Chemistry JAMB 1997 Q3 ✓ Answer: D

The section PQ indicate that X is

A

a mixture of salt

B

a hydrated salt

C

an ionic salt

D

a pure compound. 4.. The section OP suggests that X is in the

Chemistry JAMB 1997 Q5 ✓ Answer: D

An element, X, format a volatile hydride XH3 with a vapour density of 17.o. The relation mass of X is

A

34.0

B

31.0

C

20.0

D

14.0

Chemistry JAMB 1997 Q7 ✓ Answer: B

If 30cm3 of oxygen diffuses through a porous plug in 7s, how long will it take 60 cm3 of chlorine to diffuse through the same plug

A

12 s

B

14 s

C

21 s

D

30 s

Chemistry JAMB 1997 Q8 ✓ Answer: C

The temperature of a body decreases when drops of liquid placed on it evaporates because

A

the atmospheric vapour pressure has a cooling effect on the body

B

a temperature gradient exists between the drops of liquid and the body

C

the heat of vapourization is drawn from the bodycausing it to cool

D

the random motion of the liquid molecules causes a cooling effect on the body.

Chemistry JAMB 1997 Q9 ✓ Answer: C

The electron configuration of two elements with similar chemical properties are represented by

A

Is22s2 2p5 and Is22s22p4

B

Is22s2 2p4 and Is22s22p63s1 C Is22s22p63s1 and Is22sI

D

Is22s2 2p4 and Is22sI

Chemistry JAMB 1997 Q10 ✓ Answer: D

In the periodic table, what is the property that decrease along the period and increases down the group

A

Atomic number

B

Electron affinity.

C

Ionization potential

D

Atomic radius.

Chemistry JAMB 1997 Q11 ✓ Answer: B

Two elements, P and Q with atomic numbers 11 and 8 respectively, combine chemically values of x and y are

A

1 and 1

B

1 and 2

C

2 and 1

D

3 and 1

Chemistry JAMB 1997 Q12 ✓ Answer: B

Oxygen is a mixture of two isotopes 16 8 O and 18 8 O with relative abundance of 90% and 10% respectively. The relative atomic mass of oxygen

A

16.0

B

16.2

C

17.0

D

18.0

Chemistry JAMB 1997 Q13 ✓ Answer: C

200cm3 of air was passed over heated copper in a syringe several times to produce copper (11) oxide. When cooled the final volume of air recorded was 158cm3. Estimate the percentage of oxygen in the air.

A

31%

B

27%

C

21%

D

19%

Chemistry JAMB 1997 Q14 ✓ Answer: D

Which of the following gases is the most dangerous pollutant

A

Hydrogen sulphide

B

Carbon (1V) oxide

C

Sulphur (1V) oxide

D

Carbon (11) oxide

Chemistry JAMB 1997 Q18 ✓ Answer: C

The hydroxyl ion concentration, (OH-), in a solution of sodium hydroxide of pH 10.0 is

A

10-10 mol dm-3

B

10-6 mol dm-3

C

10-4 mol dm-3

D

10-2 mol dm-3 [PAGE 48]

Chemistry JAMB 1997 Q19 ✓ Answer: D

Which of the aqueous solution with the pH values below will liberate hydrogen when it reacts with magnesium metal?

A

13.0

B

7.0

C

6.5

D

3.0

Chemistry JAMB 1997 Q20 ✓ Answer: C

Given that 15.00cm3 of H2SO4 was required to completely neutralize 25.00 cm3 of 0.125 mol dm-3 NaOH, calculate the molar concentration of the acid solution.

A

0.925 mol dm-3

B

0.156 mol dm-3

C

0.104 mol dm-3

D

0.023 mol dm –3

Chemistry JAMB 1997 Q21 ✓ Answer: A

When platinum electrodes are used during the electrolysis of copper (11) tetraoxosulphate (1V) solution, the solution gets progressively

A

acidic

B

basic

C

neutral

D

amphoteric

Chemistry JAMB 1997 Q22 ✓ Answer: C

How many faradays of electricity are required to deposit 0.20 mole of nickel, if 0.10 faraday of electricity deposited 2.98 g of nickel during electrolysis of its aqueous solution?

A

0.20

B

0.30

C

0.40

D

0.50 ( Ni =058.7, IF=96 500C mol-1)

Chemistry JAMB 1997 Q23 ✓ Answer: B

What is the oxidation unmber of Z in K3 ZCI6 ?

A

-3

B

+3

C

–6

D

+6

Chemistry JAMB 1997 Q25 ✓ Answer: B

2SO 2(g)+O2(g) 2 SO3(g) In the reaction above, the standard heats of formation of SO2(g) and SO3(g) are –297 kJ mol-1 and –396 kJ mol-1 respectively. The heat change of the reaction is

A

-99 kJ mol-1

B

–198 kJ mol-1

C

+198 kJ mol-1

D

+683 kJ mol-1

Chemistry JAMB 1997 Q26 ✓ Answer: A

½ N2(g) +1/2 O2(g); H- = 89 kJ mol-1 If the entropy change for the reaction above at 25oC is 11.8 J, calculate the change in free energy, G , for the reaction at 250C

A

88.71 KJ

B

85.48 kJ

C

–204.00 kJ

D

–3427.40 kJ

Chemistry JAMB 1997 Q27 ✓ Answer: C

If the rate law obtained for a given reaction is rate=k(X)n(Y)m, what is the overall order of the reaction?

A

nm

B

n

C

n+m

D

n-m

Chemistry JAMB 1997 Q28 ✓ Answer: A

One method of driving the positon of equilibrium of an endothermic reaction forward is to

A

increase temperature at constant pressure

B

decrease pressure at constant temperature

C

cool down the apparatus with water

D

decrease temperature at constant pressure.

Chemistry JAMB 1997 Q29 ✓ Answer: D

Oxidation of concentrated hydrochloric acid with manganese(1V) oxide liberates a gas used in the

A

manufacture of tooth pastes

B

treatment of simple goiter

C

valcanization of rubber

D

sterilization of water.

Chemistry JAMB 1997 Q30 ✓ Answer: C

mE + nF pG + qH In the equation above, the equlibrium constant is given by

A

(E)m(F)n (G)p(H)q

B

(E)(F) (G) (H)

C

(G)p(H)q (E)m(F)n

D

(G)(H) (E) (F)

Chemistry JAMB 1997 Q32 ✓ Answer: A

Coal gas is made up to carbon (11) oxide, hydrogen and

A

nitrogen

B

air

C

argon

D

methane

Chemistry JAMB 1997 Q33 ✓ Answer: C

In the diagram above, the gas Y could be

A

hydrogen chloride

B

oxygen

C

carbon (1V) oxide

D

chlorine.

Chemistry JAMB 1997 Q34 ✓ Answer: D

2X- (aq) + MnO2(s) + 4H+ (aq) X2(g) + Mn2+ (aq) + 2H2O(1) [PAGE 49] The reaction above can be used for the laboratory preparation of all halogens except fluorine because it is

A

a poisonous gas

B

an oxidizing agent

C

electronegative in nature

D

highly reactive.

Chemistry JAMB 1997 Q35 ✓ Answer: A

The reaction that occurs during the laboratory test for the presence of tetraoxosulphate (V1)

A

SO2- 4(aq) + Ba2+ (aq) dilHNO3 BaSO4

B

Cu(s) +4H+ (aq) + 2SO2- 4(aq) CuSO4(s) + 2H2O(1) +SO2(g)

C

4H+ (aq)+ 2SO2-4(aq) +2e- SO2- 4(aq) +2H2O(1) + SO2(g)

D

CuO(s) + 2H+ (aq) + SO2- 4(aq) CuSO4(aq)+H2O(1)

Chemistry JAMB 1997 Q36 ✓ Answer: B

The removal of rust from iron by treatment with tetraoxosulphate (V1) acid is based on the

A

hydrolysis of the iron

B

reaction of acid with base

C

oxidation of the rust

D

dehydration of the iron.

Chemistry JAMB 1997 Q37 ✓ Answer: D

Which of the following additives could improve the quality of steel?

A

Silicon

B

Sulphur and phosphorus

C

Carbon.

D

Chromium and nickel.

Chemistry JAMB 1997 Q38 ✓ Answer: A

Sodium hydroxide is prepared commercially from sodium chloride solution by.

A

electrolysis using mercury as cathode

B

hydrolysis in steam using a catal.yst

C

electrolysis using iron as anode

D

treating sodium chloride with ammonia and carbon (1V) oxide. A sample of a substance containing only C and H burns in excess O2 to yield 4.4 g of CO2 and 2.7 g of H2O. The empirical formular of the substance is

Chemistry JAMB 1997 Q40 ✓ Answer: B

An undesirable paraffin in the petroleum industry which is particularly prone to knocking is

A

iso-octane

B

n-heptane

C

iso-heptane

D

n-octane CH3

Chemistry JAMB 1997 Q41 ✓ Answer: A

CH3 CH CH CH2 CH CH3 CH2 CH3 CH3 The IUPAC nomenclature of the organic compund with the above structural formular is

A

3-ethyl-2, 5-dimethylhexane

B

4-ethyl-2, 5-dimethylexane

C

3-ethyl-1, 1, 4-trimethypentane

D

3-ethyl-2,5,5-trimethypentane

Chemistry JAMB 1997 Q42 ✓ Answer: B

The reaction of an alkanol with an alkanoic acid in the presence of concentrated H2SO4 will produce an

A

Alkanal

B

Alkanonate

C

Alkanone

D

Alkayne.

Chemistry JAMB 1997 Q43 ✓ Answer: A

The final product of the reaction of ethyne with hydrogen iodide is

A

CH3 CHI2

B

CH2I CH21

C

CH3 CI3 D CH2 =CHI CH3

Chemistry JAMB 1997 Q45 ✓ Answer: A

Aromatic and aliphatic hydrocarbons can be distinguished from each other by the

A

action of bromine

B

use of polymerization reaction.

C

Action of heat

D

Use of oxidation reaction

Chemistry JAMB 1997 Q45 ✓ Answer: B

Synthesis detergents are preferred to soap for laundry using hard water because

A

detergent are water soluble while soap not

B

the calcium salts of detergent are water soluble

C

the magnesium salt of soap is soluble in hard water

D

soap does not have a hydrocarbon terminal chain.

Chemistry JAMB 1997 Q46 ✓ Answer: B

The role of sodium chloride in the preparation of soap is to

A

purify the soap

B

separate the soap from glycerol

C

accelerate the decomposition of the fat or oil

D

react with glycerol. O CH3CH2=CH2- C - H

Chemistry JAMB 1997 Q46 ✓ Answer: D

The synthetic rubber obtained by the polymerization of chlorobutadiene in the presence of sodium is called

A

Teflon

B

Isoprene

C

Polythene

D

Neoprene

Chemistry JAMB 1997 Q47 ✓ Answer: B

The functional group represented in the compound above is

A

alkanol

B

alkanal

C

alkanone

D

alkanoate

Chemistry JAMB 1997 Q47 ✓ Answer: D

25cm3 of 0.02 M KOH neutralized 0.03 g of a monobasic organic acid having the general formula CnH2n+1COOH. The molecular formula of the acid is

A

HCOOH

B

C2H5COOH

C

CH3COOH

D

C3H7COOH (C= 12, H=1, 0=16) When Fehling’s solution is added to two isomeric carbonyl compounds X and Y with the molecular formula C5H10O, compound X gives a red precipitate while Y does not react. It can be inferred that X is O A .CH3 C CH2 CH2 CH3

Chemistry JAMB 1997 Q48 ✓ Answer: B

CxHy + 4O2 3CO2 + 2H2O. The hydrocarbon, Cx Hy in the reaction above is

A

propane

B

propene

C

propyne

D

propanone.

Chemistry JAMB 1997 Q49 ✓ Answer: B

An example of a secondary amine is

A

propylene

B

di-butylamine C . methylamine

D

trimethylamine.

Chemistry JAMB 1997 Q50 ✓ Answer: D

The relatively high boiling points of alkanol are due to

A

ionic bonding

B

aromatic character

C

covalent bonding

D

hydrogen bonding.

JAMB Chemistry 1997 past questions