Hess's Law Problem (8.55 in the Sixth Edition)

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KatelinTanjuaquio 1L
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Hess's Law Problem (8.55 in the Sixth Edition)

Postby KatelinTanjuaquio 1L » Fri Mar 15, 2019 10:13 pm

I was having trouble with the question below:

Screen Shot 2019-03-15 at 10.11.24 PM.png


However, when I was computing it, I could not figure out how to cancel oxygen. When I looked at the solutions manual, I don't understand why they multiplied only oxygen by 3/2 in the second equation, but not the rest of the substances or the enthalpy. Could someone please explain?

Screen Shot 2019-03-15 at 10.09.53 PM.png

Chem_Mod
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Re: Hess's Law Problem (8.55 in the Sixth Edition)

Postby Chem_Mod » Fri Mar 15, 2019 11:35 pm

The second reaction in the question is not balanced, the 3/2 is used to balance the reaction.

Lydia Luong 4L
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Re: Hess's Law Problem (8.55 in the Sixth Edition)

Postby Lydia Luong 4L » Sat Mar 16, 2019 12:45 am

We must always make sure our equations are balanced first before we do anything else. Since there were 3 Oxygens in the products side, we must multiply Oxygen by 3/2 to balance the equation.


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