Answer:
k is 9.1×10^-3 min^-1
Explanation:
Rate for a first-order reaction is kC
Rate = kC = change in concentration/time
C = 0.501 M
Co = 0.722 M
Change in concentration = Co - C = 0.722 - 0.501 = 0.221 M
Time = 48.5 min
k×0.501 = 0.221/48.5
0.501k = 4.56×10^-3
k = 4.56×10^-3/0.501 = 9.1×10^-3 min^-1