The rate constant for this first-order reaction is 0.0442 s−1 at 300 °C.

Question

A⟶products

If the initial mass of A is 18.00 g, calculate the mass of A remaining after 0.791 min.

Mass of A: ___ g

Answer 1

First find the half life of the reaction with half life = ln(2) / k = 0.693 / 0.0442 = 15.68 seconds

Divide by 60 to convert half life into minutes = 0.2614 minutes

Determine the number of half lives that have past: 0.791 min / 0.2614 min = 3 half lives

Initial mass / number of half lives: 18.00 g / 2³ half lives = 2.25 g