# The following data were obtained during the first order thermal decomposition of SO2Cl2 at a constant volume : SO2Cl2 (g) → SO2 (g) + Cl2 (g) - Chemistry

Sum

The following data were obtained during the first order thermal decomposition of SO2Cl2 at a constant volume :

SO2Cl2 (g) → SO2 (g) + Cl2 (g)

 Experiment Time/s–1 Total pressure/atm 1 0 0.4 2 100 0.7

Calculate the rate constant.

(Given : log 4 = 0.6021, log 2 = 0.3010)

#### Solution 1

The given reaction is as follows:

SO2Cl2 (g) → SO2(g)+Cl2(g)

Also given:

 Experiment Time/s–1 Total pressure/atm 1 0 0.4 2 100 0.7

The rate constant k can be calculated as follows:

k=2.303/tlog

when t= 100s, k = 2.303/(100s)log

k = 2.303/(100s)log

k=2.303/(100s) log 4

k = 2.303/(100s)xx0.6021

k = 1.39 x 10-2s-1

Therefore, the rate constant is 1.39 x 10-2s-1

#### Solution 2

The thermal decomposition of SO2Cl2 at a constant volume is represented by the following equation:

SO2Cl2SO2(g) + Cl2(g)

At t =0          P0             0               0

At t=t            P0 p       p               p

After time t, total pressure is given as:

Pt =(P0p) + p + p

Pt = P0 + p

This, on rearrangement, gives:

p = Pt − P0

∴ P0p=P0(PtP0)= 2P0 − Pt

For the first-order reaction, we have:

k=2.303/tlog   P_0/(P_0 - p)

=2.303/tlog  P_0/(P_0 - p)

t = 100 s

k = 2.303/100log  0.42/(0.4 - 0.7) = 1.386 xx 10^(-2)s-1

Concept: Factors Influencing Rate of a Reaction
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