Jamb Chemistry 1989 Past Questions and Answers

Question 21:

• JAMB 1989

An element, Z froms an anion whose formula is [Z(CN)₆]^y. If Z has an oxidation number of +2, what is the value of y?

A. - 2
B. - 3
C. - 4
D. - 5

Question 22:

• JAMB 1989

The combustion of ethene, C ₂H ₄, is given by the equation C ₂H ₄ + 30 ₂ → 2CO₂ + 2H₂ O; ∆H = - 1428 KJ. If the molar heats of formation of water and carbon (IV) oxide are - 286 kJ and - 396 kJ respectively, calculate the molar heat of formation of ethene in KJ

A. - 2792
B. + 2792
C. - 64
D. + 64

Question 23:

• JAMB 1989

Which of the following represents the balanced equation for the reaction of copper with concentrated trioxonitrate (V) acid?

A. Cu _(s) + 2HNO _3(aq) → Cu (NO ₃) _2(aq) + H _2(g)
B. Cu _(s) + 4HNO _3(aq) → Cu (NO ₃) _2(aq) + 2H ₂O ₍₁₎ + 2NO _2(g)
C. 3Cu _(s) + 8HNO_3(aq) → 3Cu (NO₃)_2(aq) + 4H₂O₍₁₎ + 2NO_(g)
D. 3Cu_(s) + 4HNO_3(aq) → 3Cu(NO ₃) _2(aq) + 2H ₂O ₍₁₎ + 2NO _(g)

Question 24:

• JAMB 1989

The catalyst used in the contact process for the manufacture of tetraoxosulphate (VI) acid is

A. Manganes (IV) oxide
B. Manganese (ll) tetraoxosulphate (VI)
C. Vanadium (V) oxide
D. Iron metal

Question 25:

• JAMB 1989

Some products of destructive distillation of coal are

A. Carbon (IV) oxide and ethanoic acid
B. Trioxocarbonate (IV) acid and methanoic acid
C. Producer gas and water gas
D. Coke and ammonia liquor