Jamb Chemistry 2012 Past Questions and Answers

Question 26:

• JAMB 2012

A metal M displaces zinc from ZnCl, solution, solution
This shows that

A. Electrons flow from zinc to M
B. M is more electropositive than zinc
C. M is more electonegative than zinc
D. Zinc is more electropositive than M

Question 27:

• JAMB 2012

CO(g) + H\(_2\) O\(_{(g)}\) → CO\(_{2(g)}\) + H\(_{2(g)}\)
Calculate the standard heat change of the reaction above, if the standard enthalpies of formation of CO\(_{2(g)}\), H\(_2\)O\(_{(g)}\) and CO\(_{(g)}\) in kJmol\(^{-1}\) are - 394, -242 and - 110 respectively.

A. + 262 KJ mol ^-1
B. - 262 KJ mol ^-1
C. + 42 KJ mol ^-1
D. - 42 KJ mol ^-1

Question 28:

• JAMB 2012

An increase in entropy can best be illustrated by

A. Mixing of gases
B. Freezing of water
C. The condensation of vapour
D. Solidifying candle wax

Question 29:

• JAMB 2012

The highest rate of production of carbon (lV) oxide can be achieved using

A. 0.05 mol ^-3HCI and 5g powdered CaCO₃
B. 0.05 mol ^-3HCI and 5g lump CaCO₃
C. 0.10 mol ^-3HCI and 5g powdered CaCO₃
D. 0.025 mol ^-3HCI and 5g powdered CaCO₃

Question 30:

• JAMB 2012

A piece of filter paper moistened with lead (ll) ethanoate solution turns black when the paper is dropped into a gas likely to be

A. Sulphur (VI) oxide
B. Hydrogen chloride
C. Sulphur (VI) oxide
D. Hydrogen sulphide