Problem: Hess's law provides a useful means of calculating energy changes that are difficult to measure directly. For instance, it is impossible to measure directly the enthalpy for the combustion of carbon to form carbon monoxide. Combustion of 1 mol of carbon with 0.5 mol of O2 produces both CO and CO2, leaving some carbon unreacted. However, solid carbon and carbon monoxide can both be completely burned in O2 to produce CO2. We can therefore use the enthalpy changes of these reactions to calculate the heat of combustion of carbon.What effect does this change have on ΔH Delta{ m H}: a reversing reaction?

FREE Expert Solution

We are asked what effect does reversing the reaction have on ΔH.


View Complete Written Solution
Problem Details

Hess's law provides a useful means of calculating energy changes that are difficult to measure directly. For instance, it is impossible to measure directly the enthalpy for the combustion of carbon to form carbon monoxide. Combustion of 1 mol of carbon with 0.5 mol of O2 produces both CO and CO2, leaving some carbon unreacted. However, solid carbon and carbon monoxide can both be completely burned in O2 to produce CO2. We can therefore use the enthalpy changes of these reactions to calculate the heat of combustion of carbon.

What effect does this change have on ΔH : a reversing reaction?

Frequently Asked Questions

What scientific concept do you need to know in order to solve this problem?

Our tutors have indicated that to solve this problem you will need to apply the Calorimetry concept. You can view video lessons to learn Calorimetry. Or if you need more Calorimetry practice, you can also practice Calorimetry practice problems.