In: Chemistry
1.) Given the following data:
C2H2(g) + 5/2 O2(g) à2CO2(g) + H2O(l) ΔH= -1300.kJ
C(s) + O2(g) àCO2(g) ΔH= -394kJ
H2(g) + O2(g) à H2O(l) ΔH= -286kJ
Use Hess’s Law to calculate ΔH for the reaction
2C(s) + H2(g) àC2H2(g)
2.) Calculate ΔH° for each of the following reactions using the data for the enthalpy of
formation in the appendix.
2Na(s) + 2H2O(l)à2NaOH(aq) + H2(g
target Reaction: 2C(s) + H2(g) ---------------> C2H2(g)
Given reactions are arranged to get the target reaction, by stiochiometric coefficient selection
-1x {C2H2(g) + 5/2 O2(g)---->2CO2(g) + H2O(l) } ΔH1= -1300.kJ
2x {C(s) + O2(g)----->CO2(g) } ΔH2= -394kJ
1x{ H2(g) + O2(g) -------> H2O(l) } ΔH3= -286kJ
Same alegrabaic operation is to be carried out on enthapy change
So ΔH target = -1(ΔH1= -1300.kJ) + 2x(ΔH2= -394kJ) + (ΔH3= -286kJ)
= 1300 +(- 788) + (-286) = 226 KJ