Question

QUESTION 3 [10 MARKS] a) Isobutane is used as a feedstock in the petrochemical industry, for example in the synthesis of isooctane. When 3.0 g of isobutene is heated to 400 C, it will change into butene. Table 2 shows the data that obtained in one experiment. After 25 minutes the mass of unreacted isobutene is remaining is found to be 0.375 g. Table 2: Experiment data Concentration of butene (min) (mol/L) Time 1.5 x10 1.24 x 10 1.00 x10 30 0.83 x10 i) Plot the data to determine the reaction order (7 Marks) ii) From the graph obtained, calculate the rate of constant (3 Marks)

Answer 1

1 10 15 20 25 30

It follows the equation: ---------------(1)

C = Col - kt

where intercept=[C₀]=1.48*10³ mol/L, slope=k=0.0225*10³ mol L^-1min^-1.

From Eq. (1), the rate can be given by

dc dt

So, it is a zeroth-order reaction.