Question

Ethyl iodide (C2H5I) decomposes at a certain temperature in the gas phase as follows: C2H5I(g) → C2H4(g) + HI(g) From the following data determine the order of the reaction and the rate constant. Time (min) [C2H5I] (M) 0.0 2.00 15.0 1.73 30.0 1.46 48.0 1.14 75.0 0.65

Answer 1

Answer:

The order of the reaction is zero and the rate constant 0.018 M/s.

Explanation:

$C_2H_5I(g)\rightarrow C_2H_4(g) + HI(g)$

The order of the reaction be = x

The rate law of the reaction ;

$R=k[C_2H_5I]^x$

1. Rate of the reaction  when concentration changes from 2.00 M to 1.73 M in interval of 0.0 minutes to 15.0 minutes.

$R=-\frac{1.73M-2.00M}{15.0 min-0.0min}=0.018 M/min$

$0.018 M/min=k[1.73 M]^x$..[1]

2. Rate of the reaction  when concentration changes from 2.00 M to 1.73 M in interval of 15.0 minutes to 30.0 minutes.

$R=-\frac{1.46 M-1.73M}{30.0 min- 15.0 min}=0.018 M/min$

$0.018 M/min=k[1.46 ]^x$...[2]

[1] ÷ [2]

$\frac{0.018 M/min}{0.018 M/min}=\frac{k[1.73 M]^x}{k[1.46 M]^x}$

x = 0

The order of the reaction 0.

The rate law of the reaction ;

$R=k[C_2H_5I]^0$

$0.018 M/min=k[1.73 M]^0$

$k=0.018 M/min$

The order of the reaction is zero and the rate constant 0.018 M/s.