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Negative sign in reactants

Posted: Fri Feb 23, 2018 9:36 am
by Carlos Gonzales 1H
For the general rate law, will the reactants always have a negative sign in front of them? Is this simply because the reactants are being decomposed?

Re: Negative sign in reactants

Posted: Fri Feb 23, 2018 10:43 am
by Hazem Nasef 1I
The reaction rate is represented as change in concentration over change in time. Since the concentration of reactants decreases as time goes on, the change in concentration is a negative value. To make the reaction rate a positive value, we always place a negative sign in front of the change in concentration of reactants.

Re: Negative sign in reactants

Posted: Fri Feb 23, 2018 2:21 pm
by 204918982
There will always be a negative sign in front of the reactants in order to make the reaction rate positive

Re: Negative sign in reactants

Posted: Fri Feb 23, 2018 3:29 pm
by Yu Chong 2H
Yes because the reactants would be decreasing, to get a positive value for rate of reaction we have to have a negative sign ahead of it.

Re: Negative sign in reactants

Posted: Fri Feb 23, 2018 7:50 pm
by Leah Thomas 2E
You can also think of it as reactants being used up so it's rate is negative since the amount is declining.

Re: Negative sign in reactants

Posted: Sun Feb 25, 2018 10:19 am
by Sandhya Rajkumar 1C
The concentration of the reactants will decrease over the reaction, so without the negative sign, the reaction rate for the reactants would be a negative number, as it is calculated from the change in concentration over the change in time. However, we want to work with positive reaction rates, so by adding a negative sign in front of the change in concentration of the reactants, we make the reaction rate positive.

Re: Negative sign in reactants

Posted: Sun Feb 25, 2018 4:51 pm
by Varsha Sivaganesh 1A
Since we are calculating the rate of the forward reaction, we are assuming that the reactants are being used up and converted into the products. Therefore, the concentration of reactants is decreasing and the change in concentration will be negative.