00:01
Our chemical reaction is, looks like 2a plus b goes to 3c.
00:14
So the rate of the reaction is going to be equal to negative, 1 over the coefficient for the reactant, a, multiplied by the change in concentration of a over change in time.
00:33
Negative, because this delta a value will be negative.
00:37
So we need to cancel that negative to get a positive rate.
00:41
The rate is always positive.
00:44
That will then be equal to negative 1 over 1, the coefficient for b, multiplied by the change in concentration of b over change in time, which will also be equal to positive 1 over 3.
01:00
Positive now, because the change in concentration of c is positive is its concentration increases rather than decreases.
01:11
But if we use the words decreases, decreases, decreases, then we really don't need the negative sign.
01:18
And i think that that's what they're suggesting here.
01:21
They tell us that the rate of decrease for a is 0 .10 molar per second...