Post Utme Obafemi Awolowo University Chemistry Past Questions and Answers

Question 6:

The amount of methane molecules, $C{H}_4$, in $8.0$ grams of methane is ____________

A. $8mol$
B. $128mol$
C. $0.5mol$
D. 3.01 \times 10^{23}\) molecules

Question 7:

The concentration of a solution obtained by dissolving $0.53g$ of pure anhydrous $N{a}_{2}C{O}_3$ in water to make $250c{m}^3$ of solution is ____________

A. $2.0\times {10}^{-5}mold{m}^{-3}$
B. $2.1gd{m}^{-3}$
C. $2.0\times {10}^{-}$
D. $5.0\times {10}^{-5}mold{m}^{-3}$

Question 8:

What is the maximum volume of $C{O}_2$ at s.t.p. that can be obtained when dilute hydrochloric acid is added to 10 grams of $CaC{O}_3$ ?
\([ Ca =40, C =12, O =16]

A. $224d{m}^3$
B. $22.4d{m}^3$
C. $0.224d{m}^3$
D. $22.4d{m}^3$

Question 9:

Sulphur (IV) oxide travels a given distance in $10sec$. How long will it take equal volume of helium to travel the same distance under the same conditions? $[S=32,O=16,He$ $=4$ ]

A. $1.6sec$
B. $40sec$
C. $5.0sec$
D. $2.5sec$

Question 10:

The volume of hydrogen gas produced at S.T.P. when $100ml$ of $2M$ hydrochloric acid reacts with exeess zine is ____________

A. $2.24d{m}^3$
B. $4.48d{m}^3$
C. $1.12d{m}^3$
D. $44.8d{m}^3$