Calculate ΔHrxn for the following reaction:
CaO(s)+CO2(g)→CaCO3(s)
Use the following reactions and given ΔH values:
Ca(s)+CO2(g)+12O2(g)→CaCO3(s),
ΔH= -812.8 kJ
2Ca(s)+O2(g)→2CaO(s), ΔH= -1269.8 kJ
See your other post above.
To calculate ΔHrxn for the given reaction, we need to use the given reactions and their ΔH values to determine the net ΔH for the target reaction. Here's how to do it step by step:
1. Write out the target reaction:
CaO(s) + CO2(g) → CaCO3(s)
2. Manipulate the given reactions to match the target reaction as much as possible:
Scale the first reaction by multiplying it with 2:
2Ca(s) + 2CO2(g) + 12O2(g) → 2CaCO3(s)
3. Reverse the second reaction to get CaO on the reactant side:
2CaO(s) → 2Ca(s) + O2(g)
4. Add the two manipulated reactions together to yield the target reaction:
2CaO(s) + 2CO2(g) + 12O2(g) + 2CaO(s) → 2CaCO3(s) + 2Ca(s) + O2(g)
5. Simplify the equation by canceling out common reactants and products:
2CO2(g) + 12O2(g) + 2CaO(s) → 2CaCO3(s) + 2Ca(s) + O2(g)
6. Write down the net ΔH for the simplified equation:
ΔHnet = ΣΔH(products) - ΣΔH(reactants)
7. Substitute the given ΔH values into the net ΔH equation:
ΔHnet = (-812.8 kJ) - (2)(-1269.8 kJ)
8. Calculate ΔHrxn:
ΔHrxn = ΔHnet
ΔHrxn = (-812.8 kJ) - (2)(-1269.8 kJ)
ΔHrxn = -812.8 kJ + 2539.6 kJ
ΔHrxn = 1726.8 kJ
Therefore, ΔHrxn for the given reaction CaO(s) + CO2(g) → CaCO3(s) is 1726.8 kJ.