Negative sign in reactants


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Carlos Gonzales 1H
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Negative sign in reactants

Postby Carlos Gonzales 1H » Fri Feb 23, 2018 9:36 am

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?

Hazem Nasef 1I
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Joined: Tue Oct 10, 2017 7:13 am

Re: Negative sign in reactants

Postby Hazem Nasef 1I » Fri Feb 23, 2018 10:43 am

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.

204918982
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Joined: Fri Sep 29, 2017 7:04 am

Re: Negative sign in reactants

Postby 204918982 » Fri Feb 23, 2018 2:21 pm

There will always be a negative sign in front of the reactants in order to make the reaction rate positive

Yu Chong 2H
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Joined: Fri Sep 29, 2017 7:05 am

Re: Negative sign in reactants

Postby Yu Chong 2H » Fri Feb 23, 2018 3:29 pm

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.

Leah Thomas 2E
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Joined: Fri Sep 29, 2017 7:06 am

Re: Negative sign in reactants

Postby Leah Thomas 2E » Fri Feb 23, 2018 7:50 pm

You can also think of it as reactants being used up so it's rate is negative since the amount is declining.

Sandhya Rajkumar 1C
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Joined: Fri Jun 23, 2017 11:40 am

Re: Negative sign in reactants

Postby Sandhya Rajkumar 1C » Sun Feb 25, 2018 10:19 am

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.

Varsha Sivaganesh 1A
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Joined: Thu Jul 13, 2017 3:00 am

Re: Negative sign in reactants

Postby Varsha Sivaganesh 1A » Sun Feb 25, 2018 4:51 pm

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.


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