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7A.3

Posted: Sun Mar 08, 2020 7:33 pm
by Labiba Sardar 2A
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)?

Re: 7A.3

Posted: Sun Mar 08, 2020 7:36 pm
by Nikki Razal 1L
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

Re: 7A.3

Posted: Sun Mar 08, 2020 7:37 pm
by Kate Osborne 1H
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.

Re: 7A.3

Posted: Mon Mar 09, 2020 1:57 pm
by Emily Vainberg 1D
For part A of this question, did you get that the rate of O2 was 1.32 moles.L-1.s-1 ?

Re: 7A.3

Posted: Mon Mar 09, 2020 2:04 pm
by Amy Pham 1D
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.