8. The half-life of a reaction was found to be inversely dependent on the concentration of the starting material. Thus, we can say that

Question

a. the reaction is zero order b.the reaction is first order
c.the reaction is second order

d. the reaction starts out first order and changes to second order after one half-life.

e. the reaction starts out second order and changes to first order after one half-life.

I think that the answer is the reaction is second order. Is this correct?

Answer 1

Here are the equations for half life for
order 0, order 1, and order 2. I didn't include order 3 because those reactions are not very common.
zero order:
half life = (Ao)/2ak

1st order:
half life = ln 2/ak

2nd order:
half life = 1/ak(Ao)

note: a and k are constants.l (Ao) is starting material concn.

You are right; it is second order. That is the only one for which the starting material is inversely dependent on the starting material, (Ao).