Problem: Consider the following reaction:2Mg(s) + O2(g)→ 2MgO(s)        ΔH = -1204 kJWhich of the following statements is true?a) This reaction is endothermic.b)  This reaction represents the formation reaction for MgO and ΔHfo (MgO) = -1204 kJ.c)  When 3.55g Mg reacts at constant pressure, the heat transferred is -87.9 kJ.d)  When 40.3g MgO(s) is decomposed into Mg(s) and O2 at constant pressure, 1204 kJ is absorbed.e)  All reactants and products are not in their standard state.

FREE Expert Solution

For this problem, analyze each choice and determine the correct statement for the given reaction:

2 Mg (s) + O2 (g) → 2 MgO (s) ΔH = -1204 kJ


a. This reaction is endothermic.

  • Recall that in thermochemistry, a reaction is considered endothermic when the reaction absorbs heat in the process. 
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Problem Details

Consider the following reaction:

2Mg(s) + O2(g)→ 2MgO(s)        ΔH = -1204 kJ

Which of the following statements is true?

a) This reaction is endothermic.

b)  This reaction represents the formation reaction for MgO and ΔHfo (MgO) = -1204 kJ.

c)  When 3.55g Mg reacts at constant pressure, the heat transferred is -87.9 kJ.

d)  When 40.3g MgO(s) is decomposed into Mg(s) and Oat constant pressure, 1204 kJ is absorbed.

e)  All reactants and products are not in their standard state.


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