## 8.65

Emily Glaser 1F
Posts: 156
Joined: Thu Jul 27, 2017 3:01 am

### 8.65

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

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

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

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

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

RenuChepuru1L
Posts: 58
Joined: Thu Jul 27, 2017 3:00 am

### Re: 8.65

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

Akash_Kapoor_1L
Posts: 52
Joined: Thu Jul 13, 2017 3:00 am
Been upvoted: 1 time

### Re: 8.65

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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