Final answer:
To calculate the NH₃ concentration at t = 15.0 seconds, assuming a first-order reaction, use the formula [A]t =
with the initial concentration and the reaction constant. The estimated concentration of NH₃ at 15.0 seconds is 0.740 M.
Step-by-step explanation:
To determine the concentration of NH₃ at t = 15.0 seconds, we need to first confirm the order of the reaction, which is not provided in the question, unfortunately. Assuming it is a first-order reaction based on provided context, the concentration at time t can be calculated using the integrated rate law for a first-order reaction:
[A]t = [A]0e-kt
Where:
- [A]t is the concentration of NH₃ at time t,
- [A]0 is the initial concentration of NH₃ ,
- k is the reaction constant, and
- t is the time (in seconds).
For the given values:
- [A]0 = 0.851 M
- k = 9.23 × 10-3 s-1
- t = 15.0 s
We get:
[A]t = 0.851 × e-(9.23 × 10-3)(15.0)
Calculating this gives:
[A]t ≈ 0.851 × e-0.13845 ≈ 0.851 × 0.870 ≈ 0.740 M
Thus, the concentration of NH₃ at 15.0 seconds is approximately 0.740 M.