Posted by Rachel on .
C2H6 > 2CH3
at a temperature where the halflife is 21 minutes.
If the initial concentration is 8.0 mM, what would the concentration be after 46.0 minutes?
How long would it take to convert 95% of C2H6 at this temperature?

Chemistry 
DrBob222,
Fist, solve for k.
k = 0.693/t_{1/2}.
The b part of the question is solved with the following.
Set No = 8.0 mM
Solve for N. Units will be in mM.
Substitute k from the first part.
ln(No/N) = kt
For c part.
Use the same equation as part b but us No = 100
N = 5
k form part a
Solve for t.
Post your work if you get stuck.