Question

Calculate δh for the reaction:

2CO₂(g) + H₂O(g) → C₂H₂(g) + 5/2O₂(g)
a) -71.2 kJ
b) 94.5 kJ
c) -283 kJ
d) 52.3 kJ

Answer 1

The enthalpy change (ΔH) for the given reaction can be calculated using Hess's law and the enthalpy changes of known reactions. By combining known reactions, we can find the enthalpy change of the desired reaction to be approximately -283.0 kJ/mol of CO.

Step-by-step explanation:

The enthalpy change (ΔH) for the given reaction can be calculated using Hess's law and the enthalpy changes of known reactions. First, we write the balanced chemical equation for the desired reaction. Then, we find two other equations for which the enthalpy changes are known and can be combined to give the desired equation.

In this case, the enthalpy change for the conversion of 2 moles of CO to CO2 is -566.0 kJ. From the given reactions, we can write two equations, reverse one of them and multiply the other by 2. By adding these equations, we can cancel out the C(s) terms and obtain the desired reaction equation.

By combining the enthalpy changes of the two component equations, we can calculate the enthalpy change for the given reaction to be approximately -283.0 kJ/mol of CO.