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Emily Glaser 1F
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Joined: Thu Jul 27, 2017 3:01 am


Postby Emily Glaser 1F » Tue Jan 23, 2018 6:48 pm

Where does the third equation come from? The third equation being 2NO + 3/2O2 --> N2O5?

Connor Kelligrew 2D
Posts: 39
Joined: Fri Sep 29, 2017 7:07 am

Re: 8.65

Postby Connor Kelligrew 2D » Tue Jan 23, 2018 8:09 pm

They added the first reaction to half of the second reaction, and I am referring to the two reactions they provide in the problem.

Personally I would avoid dealing with fractions in these calculations if possible, and would not approach the problem like this.

Payton Schwesinger 1J
Posts: 45
Joined: Fri Sep 29, 2017 7:04 am

Re: 8.65

Postby Payton Schwesinger 1J » Tue Jan 23, 2018 10:04 pm

I was confused on this too.. Is there another way to do this without adding them together and ending up with fractions?

Evelyn L 1H
Posts: 67
Joined: Fri Sep 29, 2017 7:05 am

Re: 8.65

Postby Evelyn L 1H » Wed Jan 24, 2018 12:07 am

I don't understand where they got the target reaction from the two given reactions. Why can't we use Hess's law to find delta H?

Phillip Winters 2F
Posts: 50
Joined: Fri Sep 29, 2017 7:05 am

Re: 8.65

Postby Phillip Winters 2F » Wed Jan 24, 2018 12:14 am

They put fractions in the reaction because they wanted to display the reaction that only produces one mole of N2O5, which would result in their being fractional coefficients for some of the reactants

Posts: 58
Joined: Thu Jul 27, 2017 3:00 am

Re: 8.65

Postby RenuChepuru1L » Wed Jan 24, 2018 5:13 pm

from what it looks like in the solution manual you're trying to achieve 5 moles of o2 and 2 moles n on the reactants and the same for products so its the best way to manipulate the two equations to cancel out different reactants and products to end up with 1 mole of n2o5 for your product

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Re: 8.65

Postby Akash_Kapoor_1L » Thu Jan 25, 2018 2:37 pm

In the solutions manual, they say that "the reaction we want is" N2 + 5/2 O2 ----> N2O5
I'm not sure where they got the reaction from. Also is there a similar example to this in the textbook, because I'm not sure what method to use to solve this.

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