Question

The enthalpy of elements in the standard states is taken as zero.Hence enthalpy of compound should be.. A should be always negative B should be always positive C.Will be equal to twice the energy of combustion D.May be positive or negative.. Please give reason for your answer

Answer 1

Answer:

Points to look for: The enthalpy change is the 'enthalpy change of hydration'. It can't be measured directly as we cannot physically measure how much energy is released when five moles of water react with one mole of copper(II) sulfate. ... The difference between the two routes is the enthalpy change of hydration.