Sulphuryl chloride, SO2Cl2, decomposes according to the following first-order reaction:

Question

SO2Cl2(g) �¨ SO2(g) + Cl2(g)

At a certain temperature, it is observed that it takes 147 minutes for 23.0% of the sulphuryl chloride to react. Calculate the half-life for the reaction in units of min.

Answer 1

ln(No/N) = kt
Take No = 100, then N = 77, t is 147 min and solve for k.
Then k = 0.693/t_1/2 and solve for t_1/2
Post your work if you get stuck.

Answer 2

how did you get No and N?

Answer 3

I just assumed 100 for No (the number of molecules at the beginning), then if 23% react, that leaves 77. You could take ANY number for No and take 23% of that and subtract from No to obtain N. OR, you could take No = No, then N = 0.77*No but it's easier to stick in a number. Does that help.