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Calculate enthalpy change?

Calculate the enthalpy change,ΔHf°, for the formation of 7 mol of stronium carbonate from its elements.

Sr(s) + C(graphite) + 3/2 O^2(g) ----> SrCO^3

The experimental information available is:

1. Sr(s) + 1/2 O^2(g) -----> SrO(s) ΔHf° = -592 kJ/mol

2. SrO(s) + CO^2(g) -----> SrCO^3 ΔHf° = -234 kJ/mol

3. C(graphite) + O^2(g) -----> CO^2(g) ΔHf° = -394 kJ/mol

1 Answer

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  • 9 years ago
    Favorite Answer

    Leave all three data equations alone. Simply add then together. The SrO will cancel as will the CO2. You will be left with your target equation.

    Since the equations are unmodified, simply add the three enthalpies to arrive at your answer.

    More Hess' Law:

    http://www.chemteam.info/Thermochem/Thermochem.htm...

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