enthalpy equations

[Savannah Mance 4G]

For 4D.5 why is the change in enthalpy equal to the heat supplied if there was expansion work done? I thought there had to be no expansion for the change in enthalpy to equal q.

[Ruby Tang 2J]

ΔH is equal to q whenever the reaction is occurring at constant pressure, a condition which is specified in the problem. I think you may be referring to the fact that there has to be no expansion in order for ΔH to be equal to ΔU (internal energy). Hope this helps!