Obafemi Awolowo University Chemistry Post Utme Past Questions and Answers

Question 6 :

The amount of methane molecules, \(CH _{4}\), in \(8.0\) grams of methane is ____________

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

Question 7 :

The concentration of a solution obtained by dissolving \(0.53 g\) of pure anhydrous \(Na _{2} CO _{3}\) in water to make \(250 cm ^{3}\) of solution is ____________

A. \(2.0 \times 10^{-5} mol dm ^{-3}\)
B. \(2.1 gdm ^{-3}\)
C. \(2.0 \times 10^{-}\)
D. \(5.0 \times 10^{-5} mol dm^{-3 }\)

Question 8 :

What is the maximum volume of \(CO _{2}\) at s.t.p. that can be obtained when dilute hydrochloric acid is added to 10 grams of \(CaCO _{3}\) ?
\([ Ca =40, C =12, O =16]

A. \(224 dm ^{3}\)
B. \(22.4 dm ^{3}\)
C. \(0.224 dm ^{3}\)
D. \(22.4 dm ^{3}\)

Question 9 :

Sulphur (IV) oxide travels a given distance in \(10 sec\). 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. \(1.6 sec\)
B. \(40 sec\)
C. \(5.0 sec\)
D. \(2.5 sec\)

Question 10 :

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

A. \(2.24 dm ^{3}\)
B. \(4.48 dm ^{3}\)
C. \(1.12 dm ^{3}\)
D. \(44.8 dm ^{3}\)