## 7A.3

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

Labiba Sardar 2A
Posts: 103
Joined: Sat Jul 20, 2019 12:15 am

### 7A.3

The combustion reaction C2H4 (g) + 3O2 (g) --> 2CO2 (g) + 2H2O (g) has a unique rate of .44 mol.L^-1.s^-1

When finding the rate at which oxygen reacts and the rate at which water forms, why do both of these rates have positive values? Shouldn't they be opposite values since one is used up in the reaction (O2) while the other is formed (H2O)?

Nikki Razal 1L
Posts: 116
Joined: Fri Aug 30, 2019 12:17 am
Been upvoted: 1 time

### Re: 7A.3

I feel like the rates would both be positive because I think they are technically the same, just working in the opposite direction. either way, the book says that positive reaction rate is the normal convention in chemical kinetics

Kate Osborne 1H
Posts: 102
Joined: Fri Aug 30, 2019 12:16 am

### Re: 7A.3

the unique rate is the same for all reactants and products in that unique reaction. so the rate at which the product forms and the reactant is used up must equal each other, so they have to have the same sign.

Emily Vainberg 1D
Posts: 102
Joined: Sat Jul 20, 2019 12:15 am

### Re: 7A.3

For part A of this question, did you get that the rate of O2 was 1.32 moles.L-1.s-1 ?

Amy Pham 1D
Posts: 103
Joined: Fri Aug 09, 2019 12:15 am

### Re: 7A.3

Emily Vainberg 1D wrote:For part A of this question, did you get that the rate of O2 was 1.32 moles.L-1.s-1 ?

Yes, this is correct! The rate of consumption of oxygen (O2) is 1.3 mols.L-1.s-1, with correct sigfigs.