Enthalpy change? chemistry help

Question

The enthalpy change for a chemical reaction is...

the temperature change

the amount of heat given off or absorbed

related to molar volume

none of the above

Answer 1

Quite simply, change in enthalpy is the amount of heat flow at constant pressure.  Its formula is change in enthalpy = (number of moles)*(constant pressure heat capacity)*(T_final - T_initial)... or H =n*Cp*delta(T).  You may also remember the fomula q=mc*delta(T), where "q" is heat.  Same equation, they mean the same thing.  It's not related to molar volume.  Enthalpy is an intrinsic variable, which means that it doesn't depend on things like mass or volume.

Answer 2

The amount of heat given off or absorbed is a reasonable though not necessarily precise answer.