Post Utme Chemistry Past Questions and Answers

Question 106:

Which of the following compounds will leave a metal residue when heated?

A. \(\mathrm{Cu}\left(\mathrm{NO}_{3}
ight)_{2}\)
B. \(\mathrm{AgNO}_{3}\)
C. \(\mathrm{K}_{2} \mathrm{CO}_{3}\)
D. \(\mathrm{Na}_{2} \mathrm{CO}_{3}\)

Question 107:

Which of the polymers contains nitrogen?

A. Nylon
B. PVC
C. Polyethene
D. Cellulose

Question 108:

A red precipitate of copper(I)dicarbide is formed when ammonium solution of copper(I) chloride is introduced into ____________

A. \(\mathrm{CH}_{2}=\mathrm{CH}-\mathrm{CH}_{2}-\mathrm{CH}_{3}\)
B. \(\mathrm{CH}_{3}-\mathrm{CH}_{2}-\mathrm{C} \equiv \mathrm{CH}\)
C. \(\mathrm{CH}_{3}-\mathrm{CH}_{2}-\mathrm{CH}^{2}-\mathrm{CH}^{3}\)
D. \(\mathrm{CH}^{3}-\mathrm{C} \equiv \mathrm{C}-\mathrm{CH}^{3}\)

Question 109:

What are the values of \(\mathrm{p} q, r\) and \(s\) respectively in the equation? \(\mathrm{pCH}_{4}+\mathrm{qO}_{2} \rightarrow \mathrm{rCO}\) \(+\mathrm{sH}_{2} \mathrm{O}\)

A. \(1,2,1,2\)
B. \(1,3,2,2\)
C. \(2,3,2,4\)
D. \(2,3,2,2\)

Question 110:

\(\mathrm{KHCO}_{3}\) is contaminated with \(\mathrm{K}_{2} \mathrm{CO}_{3}\) as impurity. If \(2.5 \mathrm{~g}\) of the impure \(\mathrm{KHCO}_{3}\) on heating produces \(0.224 \mathrm{dm}^{3}\) of \(\mathrm{CO}_{2}\) at s.t.p., calculate the percentage of \(\mathrm{K}_{2} \mathrm{CO}_{3}\) impurity. \((\mathrm{K}=39, \mathrm{H}=1\), \(C=12,0=16)\)

A. \(30 \%\)
B. \(40 \%\)
C. \(10 \%\)
D. \(20 \%\)