Page 04 8. A reaction must be exothermic if A both ∆G ° and ∆S ° are negative B both ∆G ° and ∆S ° are positive C ∆G ° is negative D ∆S ° is positive. 9. For the reaction A + B ↓ C the following data were obtained. Experiment Initial concentration of A (mol l−1) Initial concentration of B (mol l−1) Initial rate of formation of C (mol l−1 s−1) 1 0·1 0·1 0·05 2 0·2 0·1 0·05 3 0·1 0·2 X Given that the rate equation is Rate = k[B]2 the value of X will be A 0·05 B 0·10 C 0·15 D 0·20. 10. The rate equation for the reaction between nitrogen monoxide and chlorine is rate = k[NO]2[Cl2] The units for the rate constant, k, in this reaction are A s−1 B mol l−1 s−1 C l mol−1 s−1 D l2 mol−2 s−1.