Question

Calculate ΔHrxn for the following reaction:

CaO(s)+CO2(g)→CaCO3(s)
Use the following reactions and the given values of ΔH for them:
Ca(s)+CO2(g)+12O2(g)→CaCO3(s),ΔH2Ca(s)+O2(g)→2CaO(s),ΔH==−812.8kJ−1269.8kJ
Express your answer to four significant figures in kilojoules.

Answer 1

To calculate ΔHrxn for the given reaction, CaO(s) + CO2(g) → CaCO3(s), use Hess's law and the given values of ΔH for the provided reactions. Reverse one equation and use another equation to add them together and find the overall ΔHrxn.

Step-by-step explanation:

To calculate ΔHrxn for the given reaction, CaO(s) + CO2(g) → CaCO3(s), we can use Hess's law and the given values of ΔH for the provided reactions.

First, we need to write two equations that can be added together to give the desired equation:

1. Reverse the equation CaCO3(s) → CaO(s) + CO2(g) to get ΔH = -177.8 kJ

2. Use the equation Ca(s) + O2(g) → 2CaO(s) with ΔH = -1269.8 kJ

Now, we can add these two equations together:

2Ca(s) + 2CO2(g) + O2(g) → 2CaCO3(s) with ΔH = -177.8 kJ + -1269.8 kJ = -1447.6 kJ

Therefore, the ΔHrxn for the given reaction is -1447.6 kJ.

Answer 2

The enthalpy change for the reaction CaO(s)+CO2(g)→CaCO3(s) is -2082.6 kJ.

Step-by-step explanation:

The enthalpy change for the reaction CaO(s)+CO2(g)→CaCO3(s) can be calculated using the information provided. We can use Hess's law and the given values of ΔH for the reactions to determine the overall enthalpy change. By adding the enthalpy changes of the provided reactions in the appropriate direction, we can calculate the enthalpy change for the desired reaction.

Using the given values of ΔH for the reactions:

1. Ca(s) + CO2(g) + 1/2O2(g) → CaCO3(s), ΔH = -812.8 kJ
2. 2Ca(s) + O2(g) → 2CaO(s), ΔH = -1269.8 kJ

We can rearrange the equations and multiply them by factors to obtain the desired reaction:

1. 2Ca(s) + 2CO2(g) + O2(g) → 2CaCO3(s), ΔH = -812.8 kJ
2. 2Ca(s) + O2(g) → 2CaO(s), ΔH = -1269.8 kJ

Now, by adding these two equations, we can cancel out the common substances and obtain the desired reaction:

CaO(s) + CO2(g) → CaCO3(s), ΔH = -2082.6 kJ