Post Utme Chemistry Past Questions and Answers

Question 1151:

\(A _{( g )}+2 B _{( g )} \rightarrow C _{( g )}\)
In the reaction represented by the equation above, the rate of appearance of \(C\) is found experimentally to be independent of the concentration of A and to increase four folds when the concentration of B is doubled. The rate law for the reaction is ____________

A. Rate \(=K[A]^{0}[B]^{4}\)
B. Rate \(= K [A]^{0}[B]^{2}\)
C. Rate \(= K [A][B]^{2}\)
D. Rate \(= K [A]^{2}[B]^{0}\)

Question 1152:

How is the equilibrium constant for the forward reaction of an equilibrium \(\left( K _{ f }\right)\) related to that of the reverse reaction \(\left( K _{r}\right)\) ?

A. \(\left( K _{+}\right)\)is the additive inverse of \(\left( K _{r}\right)
B. \left( K _{1}\right)\) is the multiplicative inverse of \(\left( K _{f}\right)\)
C. \(\left( K _{ r }\right)\) is the same as \(\left( K _{f}\right) \)
D. The product of \(\left( K _{r}\right)\) and \(\left( K _{f}\right)\) is zero

Question 1153:

What is the concentration of \(OH ^{-}\)ions of an aqueous solution of \(pH 4.4\) ?

A. \(9.600 \times 10^{-10} moldm ^{-3}\)
B. \(2.512 \times\) \(10^{-10}\) moldm \(^{-3}\)
C. \(9.600 \times 10^{-11}\) moldm \(^{-3}\)
D. \(2.512 \times 10^{-11}\) moldm\(^{-3}\)

Question 1154:

Consider the reaction
\(2 A _{( g )} \rightleftharpoons B _{( g )}+ C _{( q )}, \Delta H =+25.6 kJ\)
Which of the following changes will favour the formation of the products of the reaction represented above, at equilibrium?

A. Decrease in temperature
B. Increase in pressure
C. Increase in temperature
D. Decrease in volume

Question 1155:

An element \({ }_{88}^{226} X\) undergoes radioactive decay by emitting two alpha particles and a beta radiation. Which of the following nuclei correctly describe the product formed by the reaction?

A. \({ }_{89}^{22}\) T
B. \({ }_{84}^{218} S\)
C. \({ }_{85}^{218} R\)
D. \({ }_{87}^{222} Q\)