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Topic: Enthalpy of Formation - Semantics  (Read 1627 times)

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Offline intex

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Enthalpy of Formation - Semantics
« on: March 29, 2014, 09:03:15 PM »
Hello everyone!

I am having a little trouble fully understanding the semantics of this question. For this answer I believe the answer is (B) - as oxygen gas exists as O2 not O. However does the (298K) on the ΔfHo(298 K) relate to both the reactants and products as referred to in answer D?

Which statement is INCORRECT concerning the ΔfHo(298 K)for MgO(s).
(A)ΔfHo(298 K)refers to a reaction which produces 1 mol of MgO(s).

(B)ΔfHo(298 K)refers to a reaction which uses O(g) and Mg(s) as reactants.

(C)ΔfHo(298 K)refers to a reaction in which both reactants and products are at standard
pressure.

(D)ΔfHo(298 K)refers to a reaction in which both reactants and products are at298 K
Thanks!

Offline mjc123

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Re: Enthalpy of Formation - Semantics
« Reply #1 on: April 03, 2014, 08:41:56 AM »
Yes, you are right, B is incorrect for the reason you give. And D is correct, both reactants and products are at 298K.

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