Question

Use the graphing method to determine the answers of the following questions:

1- What is the order of the reaction?

2- Calculate the reaction rate with the appropriate units

3- Calculate the half-life t1/2 The data table is given below (carried at 430oC)

C4H8 (g) → 2C2H4 (g)

Time (s)	Pressure C4H8 (mmHg)
0	400
2000	316
4000	248
6000	196
8000	155
10000	122

Answer 1

First Plot ln(Pressure) vs Time to get the plot using excel or origin software. By inspection, the plot of ln(P) vs time is linear, and the plot of 1/Pa vs time is not. When ln P_C4H8 is plotted as a function of time, a straight line results. - The process is first-order. - k is the negative slope: 1.19 times 10^-4 2. Rate = -Delta P_C4H_8/Delta t = k P_C4H8 = 0 3. t1/2 for first order reaction is expressed as t1/2 = 0.693/k = 0.693/(1.19 x 10^-4) = 5.82 x 10^-3 s

First Plot ln(Pressure) vs Time to get the plot using excel or origin software.

By inspection, the plot of ln(P) vs time is linear, and the plot of 1/Pa vs time is not.

When ln P_C4H8 is plotted as a function of time, a straight line results.

- The process is first-order.

- k is the negative slope: 1.19 x 10^-4

2.

Rate = - $\Delta$ P_C4H8 / $\Delta$ t = k P_C4H8 = ()

3.

t1/2 for first order reaction is expressed as

t1/2 = 0.693 / k

= 0.693 / (1.19 x 10^-4)

= 5.82 x 10^-3 s