1. Calculating ΔHfθ from combustion data
Find ΔHfθ of ethyne C2H2 given the following combustion data
ΔHcθ C2H2 (g) = kJmol-1
C (s) = -394 kJmol-1
H2 (g) = -286 kJmol-1
Find ΔHfθ of propan-1-ol C3H7OH given the following combustion data
ΔHcθ C3H7OH (l) = kJmol-1
C (s) = -394 kJmol-1
H2 (g) = -286 kJmol-1
Ans: +226kJmol-1
Ans: -316kJmol-1

2. Calculating ΔHrθ from formation data
Calculate ΔHrθ for the following reaction:
CH2=CH2(g) + H2(g) CH3CH3(g)
ΔHfθ ethene = +52kJmol-1
ΔHfθ ethane = -85kJmol-1
Calculate ΔHrθ for the reaction:
CaCO3(s) CaO(s) + CO2(g)
ΔHfθ CaCO3= -1207kJmol-1
CaO = -635kJmol-1
CO2 = -394kJmol-1
Ans: -137kJmol-1
Ans: +178kJmol-1