Question

Use standard heats of formation calculate ΔHrxn for following: a.) NaOH(s) + HCl(g) -> NaCl(s) +H2O(g) b.) 2CO(g) + O2(g) -> 2CO2(g)?

Answer 1

do you have a table with the ΔHf?

Answer 2

http://en.wikipedia.org/wiki/Standard_enthalpy_change_of_formation_%28data_table%29

Answer 3

I dont understand how to incorporate it with what the question is asking...@Cuanchi

Answer 4

@Cuanchi

Answer 5

ΔHº = ∑ΔvpΔHºf(products) - ∑Δ vrΔHºf(reactants) so this means that you add up the sum of the ΔH's of the products and subtract away the ΔH of the reactants

a) NaOH(s) + HCl(g) -> NaCl(s) +H2O(g)

(ΔHºf NaCl(s) +ΔHºf H2O(g))-(ΔHºf NaOH(s)+ΔHºf HCl(g))=ΔHrxn

b.) 2CO(g) + O2(g) -> 2CO2(g)

(2* ΔHºf CO2(g) -(2*ΔHºf CO(g)+ΔHºf O2(g))=ΔHrxn

Note: if you have 2 o "n" moles of the compound you have to multiply by 2 o "n" the value of the ΔHºf
For pure elements in standard conditions the ΔHºf =0. in your case that apply to the O2