Can you handle the enthalpy?

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Presentation transcript:

Can you handle the enthalpy? Solve these Hess’s Law Problems!

Question 1 Find the standard enthalpy for the reaction: Given that: C(s) + ½O2(g)  CO(g) Given that: C(s) + O2(g)  CO2(g) ΔH= -394 kJ CO2(g)  CO(g) + ½O2(g) ΔH= 283 kJ Answer: -111 kJ

Question 2 Find the standard enthalpy for the reaction: Given that: Fe2O3 + 2Al  Al2O3 + 2Fe Given that: 2Al + 3/2O2  Al2O3 ΔH= -1676 kJ 2Fe + 3/2O2  Fe2O3 ΔH= -824 kJ Answer: -852 kJ

Question 3 Find the standard enthalpy for the reaction: Given that: 2C2H6 + 7O2  4CO2 + 6H2O Given that: C2H4 + 3O2  2CO2 + 2H2O ΔH= -1323 kJ C2H4 + H2  C2H6 ΔH= -137 kJ H2 + ½O2  H2O ΔH= -242 kJ Answer: -2856 kJ

Question 4 Find the change in enthalpy for the reaction: Given that: NH4NO3  NH4+ + NO3- Given that: Answer: 28.05 kJ Substance ΔHf NH4NO3 -365.56 kJ NH4+ -132.51 kJ NO3- -205.00 kJ

Question 5 Find the standard enthalpy for the reaction: Given that: C2H4 + Cl2  C2H3Cl + HCl Given that: C2H4 + HCl  C2H5Cl ΔH= -65 kJ C2H3Cl + H2  C2H5Cl ΔH= -140 kJ H2 + Cl2  2HCl ΔH= -185 kJ Answer: -110 kJ

Question 6 Find the change in enthalpy for the reaction: Given that: 2H2S + 3O2  2H2O + 2SO2 Given that: Answer: -1123.6 kJ Substance ΔHf H2S -20.1 kJ O2 0.0 kJ H2O -285.8 kJ SO2 -296.1 kJ

Question 7 Find the standard enthalpy for the reaction: Given that: CaCO3 + 2HCl  CaCl2 + CO2 + H2O Given that: CaCO3  CaO + CO2 ΔH= 175 kJ Ca(OH)2  H2O + CaO ΔH= 67 kJ Ca(OH)2 + 2HCl  CaCl2 + 2H2O ΔH= -198 kJ Answer: -90 kJ