We can solve this problem by assuming that the decay of cyclopropane follows a 1st order rate of reaction. So that the equation for decay follows the expression:
A = Ao e^(- k t)
Where,
A = amount remaining at
time t = unknown (what to solve for)
Ao = amount at time zero = 0.00560
M
k = rate constant
t = time = 1.50 hours or 5400 s
The rate constant should be given in the problem which I think you forgot to include. For the sake of calculation, I will assume a rate constant which I found in other sources:
k = 5.29× 10^–4 s–1 (plug in the correct k value)
Plugging in the values in the 1st equation:
A = 0.00560 M * e^(-5.29 × 10^–4 s–1 * 5400 s )
A = 3.218 × 10^–4 M (simplify as necessary)
