question archive The standard heat of formation, ΔH?f, is defined as the enthalpy change for the formation of one mole of substance from its constituent elements in their standard states
The standard heat of formation, ΔH?f, is defined as the enthalpy change for the formation of one mole of substance from its constituent elements in their standard states
Subject:ChemistryPrice: Bought3
The standard heat of formation, ΔH?f, is defined as the enthalpy change for the formation of one mole of substance from its constituent elements in their standard states. Thus, elements in their standard states have ΔH?f=0. Heat of formation values can be used to calculate the enthalpy change of any reaction.
Consider, for example, the reaction
2NO(g)+O2(g)?2NO2(g)
with heat of formation values given by the following table:
Substance ΔH?f(kJ/mol)
NO(g) 90.2
O2(g) 0
NO2(g) 33.2
For which of the following reactions is ΔH?rxn equal to ΔH?f of the product(s)?You do not need to look up any values to answer this question.
List all that apply.
A. 2Li(s)+Cl2(g)→2LiCl(s)
B. 2H2(g)+O2(g)→2H2O(g)
C. H2(g)+12O2(g)→H2O(g)
D. Li(s)+12Cl2(g)→LiCl(s)
E. H2O2(g)→12O2(g)+H2O(g)
F. Li(s)+12Cl2(l)→LiCl(s)
