Answer: a) The concentration after 8.8min is 0.17 M
b) Time taken for the concentration of cyclopropane to decrease from 0.25M to 0.15M is 687 seconds.
Explanation:
Expression for rate law for first order kinetics is given by:

where,
k = rate constant
t = age of sample
a = let initial amount of the reactant
a - x = amount left after decay process
a) concentration after 8.8 min:



b) for concentration to decrease from 0.25M to 0.15M


The gas particles move faster.
Solid - made up of tightly packed particles, which gives it a solid shape.
Gas - made up of very loose particles, giving it more freedom to roam around as a gas
Liquid - fills into whatever it gets put in, basically takes the shape of the object its in
The thing that it is called is it is called the atomic number of the thing