Section B: Numerical Problems in Chemical Kinetics

Question B1: Temperature-dependence of a first-order reaction

The thermal decomposition of gaseous dimethylether, (CH₂)₂O, to form methane (CH₂), hydrogen (H₂) and

carbon monoxide (CO), follows the single-step reaction given in equation (B.1):

(CH₂)20(g) → CH₂(g) + H₂(g) + CO(g)

Question B2: Kinetics of a reversible, first-order reaction

The acid-catalysed conversion of y-hydroxybutyric acid (GHBA) into its lactone, y-butyrolactone (GBL) is a

reversible reaction. The GHBA to GBL forward reaction is first-order with respect to the GHBA

concentration; the GBL to GHBA reverse reaction is first-order with respect to the GBL concentration.

An experimental study of the kinetics of this reaction was undertaken in 0.2 mol L hydrochloric acid (HCI) at

298 K. The initial concentration of GHBA was 18.23 x 10³ mol L¹. The concentration of GBL in solution was

followed as a function of time (t), as indicated in Table B.3.

Question B3: Heterogeneous kinetics

Carbon monoxide (CO) is found to adsorb onto a specific crystallographic surface of a particular transition metal single crystal. In an experiment, the number of CO molecules adsorbed per square metre of the surface, N, was measured as a function of CO gas pressure, Poo, at 400 K, and gave rise to the results reported in Table B.4.