Question

The rate law for the decomposition of phosphine (PH3) is below. It takes 120. s for 1.00 M PH3 to decrease to 0.250 M. How much time is required for 4.00 M PH3 to decrease to a concentration of 0.320 M?

Answer 1

Answer: 588.8 seconds

Explanation:

1.00 - 0.25 = 0.75M

4.00 - 0.320 = 3.68M

Therefore,

0.75M in 120 seconds

3.68M in x seconds

Cross multiply:

0.75*x = 120*3.68

x = 120*3.68/0.75

x = 588.8 seconds