Question

For the reaction: 2 A+B 3 C the rate of disappearance of B was 0.30 M/s. What is the rate of disappearance of A and the rate of appearance of C?

Answer 1

rA = 0.60 M/s

rC = 0.90 M/s

Step-by-step explanation:

Let's consider the following reaction:

2 A+B ⇒ 3 C

The rate of each substance can be calculated like the change in its concentration divided by the change in time. Given the rate must always be positive, we add a minus sign before the reactants change in concentration.

`rA=-(\Delta[A] )/(\Delta t)`

`rB=-(\Delta[B] )/(\Delta t)`

`rC=(\Delta[C] )/(\Delta t)`

The rate of the reaction is equal to the rate of each substance divided by its stoichiometric coefficient.

`r= (rA)/(2) =(rB)/(1) =(rC)/(3)`

The rate of disappearance of B is 0.30 M/s.

The rate of disappearance of A is:

`(rA)/(2) =(rB)/(1)\\rA = 2 * rB = 2 * 0.30 M/s = 0.60 M/s`

The rate of appearance of C is:

`(rB)/(1) =(rC)/(3)\\rC = 3 * rB = 3 * 0.30 M/s = 0.90 M/s`