Jamb Chemistry 1983 Past Questions and Answers

Question 6:

• JAMB 1983

If an element has the electronic configuration 1s ² 2s² 2p³ 3s² 3p⁴, it is

A. A metal
B. An alkaline earth metal
C. An s-block element
D. A p-Block element
E. A transition element

Question 7:

• JAMB 1983

Some copper (ll) sulphate pentahydrate (CuSO₄ 5H₂O), was heated at 120 ^oC with the following results. Wt of crucible = 10.00 g; Wt of crucible + CuSO₄ 5H₂O =14.98g; Wt of crucible + residue = 13.54 g. How many molecules of water of crystalization were lost?
[H = 1, Cu = 63.5, O = 16, S = 32]

A. 1
B. 2
C. 3
D. 4
E. 5

Question 8:

• JAMB 1983

The three-dimensional shape of methane is

A. Hexagonal
B. Trigonal
C. Linear
D. Tetrahedral
E. Cubical

Question 9:

• JAMB 1983

An unknown organic compound X has a relative molecular mass of 180. It is a colourless crystaline solid, readily soluble in water. X contains the elements C, H and O in the atomic ratio 1: 2:1. The compound has a sweet teste and melts on heating. In the presence of yeast and in the absence of air, X is converted to compound Y and a colourless gas. Compound Y reacts with sodium metal to produce a gas Z which gives a 'pop' sound with a glowing splint. Y also reacts with ethanoic acid to give a sweet smelling compound W.
Compound W is

A. A soap
B. An oil
C. An alkane
D. An ester
E. Sucrose

Question 10:

• JAMB 1983

An unknown organic compound X has a relative molecular mass of 180. It is a colourless crystaline solid, readily soluble in water. X contains the elements C, H and O in the atomic ratio 1: 2:1. The compound has a sweet teste and melts on heating. In the presence of yeast and in the absence of air, X is converted to compound Y and a colourless gas. Compound Y reacts with sodium metal to produce a gas Z which gives a 'pop' sound with a glowing splint. Y also reacts with ethanoic acid to give a sweet smelling compound W.
The molecular formula of X is

A. C₁₂H₂₂O₁₁
B. C₆H₁₂O₆
C. C₃H₆O ₃
D. C₇H₁₄O₇
E. C₁₂H₆O₄