Question

3. The heat of formation of substance are
a. positive or negative
c. always positive
b. always negative
d. always zero​

Answer 1

Answer:

Heat of formation, also called standard heat of formation, enthalpy of formation, or standard enthalpy of formation, the amount of heat absorbed or evolved when one mole of a compound is formed from its constituent elements, each substance being in its normal physical state (gas, liquid, or solid).