## rate of a reaction

$aR \to bP, Rate = -\frac{1}{a} \frac{d[R]}{dt} = \frac{1}{b}\frac{d[P]}{dt}$

Anaranjo
Posts: 14
Joined: Wed Nov 18, 2015 3:00 am

### rate of a reaction

9. A scientist conducts an experiment to determine the rate of the following reaction: N2(g) + O2(g) → 2NO(g)
If the initial concentration of N2 was 0.500 M and the concentration of N2 was 0.450 M after 0.100 s, what is the rate of the reaction?
a. 0.500 M/s d. 10.0 M/s
b. 1.00 M/s e. 0.250 M/s
c. 5.00 M/s

Kimberly_Rivera_3K
Posts: 10
Joined: Fri Jul 15, 2016 3:00 am

### Re: rate of a reaction

Anaranjo wrote:9. A scientist conducts an experiment to determine the rate of the following reaction: N2(g) + O2(g) → 2NO(g)
If the initial concentration of N2 was 0.500 M and the concentration of N2 was 0.450 M after 0.100 s, what is the rate of the reaction?
a. 0.500 M/s d. 10.0 M/s
b. 1.00 M/s e. 0.250 M/s
c. 5.00 M/s

The rate of this reaction will be the change in concentration of N2 (0.050 M) over the change in time (0.100 s), which should be a. 0.500 M/s.

The rate here shouldn't be negative, even thought the change in concentration is "negative." We're focused here on the amount of N2 changing over time.

Hope this helps!

Jenna Smith 3F
Posts: 10
Joined: Wed Sep 21, 2016 2:55 pm

### Re: rate of a reaction

To calculate the rate here, you must divide the change in concentration (units=M) by the change in time (units=s). The change in concentration is 0.5-0.45=0.05M. The change in time is 0.1s. 0.05M/0.1s=0.5M/s, so the answer is a.