## Negative in 15.5

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

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Caitlin Mispagel 1D
Posts: 47
Joined: Tue Oct 10, 2017 7:13 am

### Negative in 15.5

Can someone explain what happens to the negative sign in 15.5 a if O2 is a product? The question reads: Ethene is a minor but important component of natural gas, and its combustion has been thoroughly studied. At a certain temperature and pressure, the unique rate of the combustion reaction C2H4(g) 3 O2(g) S 2 CO2(g) 2 H2O(g) is
0.44 mol L 1 s 1. (a) What is the rate at which oxygen reacts?

Cynthia Tsang
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### Re: Negative in 15.5

Since the question is asking for the rate at which O2 reacts, the negative is implied with the question.

Joyce Lee 1C
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### Re: Negative in 15.5

^^^The answer above is corrected. It really depends on the wording of the question. For example, the rate at which oxygen is consumed would be negative because the oxygen is consumed and thus the amount of oxygen decreases. However, if the question asked for the rate at which oxygen is consumed, the answer would be a positive number.

Nisarg Shah 1C
Posts: 54
Joined: Sat Jul 22, 2017 3:00 am

### Re: Negative in 15.5

It's kind of like velocity, we prefer it to be positive, but depending on the wording it could be written as positive or negative.

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