# chemistry

Given the thermochemical equation:

2 Al(s) + 3/2 O2(g) > Al2O3(s) ΔH = -95.7 kJ

find the heat of reaction, ΔH, for the following reaction:

2 Al2O3(s)> 4 Al(s) + 3 O2(g)
Select one:
a. -95.7 kJ
b. +95.7 kJ
c. -47.8 kJ
d. +47.8 kJ
e. +191.4 kJ

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1. You have the reaction as shown. You want the reverse reaction and double that. So take dH that you have, change the sign (because of the reversal) and double it.

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2. would it be a positive or a negative though?

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posted by tal
3. it would be e...

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posted by tal
4. yes.
You reversed the sign because the reaction is reversed. So that makes it positive. Then double that for e.

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5. thank you !!!

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posted by tal

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