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WorksheetsHess's Law
Total questions: 6
Worksheet time: 11mins
Which statements about Hess's law are correct?
I. Itis an expression of the Law of Conservation of Energy
II. It can be used to indirectly determine the enthalpy of formation of a substance.
III. The overall enthalpy change for a reaction is independent of the reaction pathway.
I and II only
I, II, and III
I and III only
II and III only
Using the equations below:
C(s) + O2(g) → CO2(g) ∆H = –390 kJ
Mn(s) + O2(g) → MnO2(s) ∆H = –520 kJ
What is ∆H (in kJ) for the following reaction?
MnO2(s) + C(s) → Mn(s) + CO2(g)
910 kJ
130 kJ
-130 kJ
-910 kJ
Using the equations below
Cu(s) + 1/2O2(g) → CuO(s) ∆H = –156 kJ
2Cu(s) + O2(g) → Cu2O(s) ∆H = –170 kJ
what is the value of ∆H (in kJ) for the following reaction?
2CuO(s) → Cu2O(s)
142 kJ
15 kJ
-15 kJ
-142 kJ
Consider the following equations.
Mg(s) + O2(g) → MgO(s) ∆H = –602 kJ
H2(g) + O2(g) → H2O(g) ∆H = –242 kJ
What is the ∆H value (in kJ) for the following reaction?
MgO(s) + H2(g) → Mg(s) + H2O(g)
-844
-360
+360
+844
The enthalpies of combustion of C(s), H2(g) and C4H9OH(l) (in kJmol-1) are as follows
C(s) + O2(g) -> CO2(g) ∆H=a
H2(g) + ½O2(g) -> H2O(l) ∆H=b
C4H9OH(l) + 6O2(g) -> 4CO2(g) + 5H2O(l) ∆H=c
What is the enthalpy change for the reaction shown below?
4C(g) + 5H2(l) + ½O2(g) -> C4H9OH(l)
