Question

question 3 (1 point)
the enthalpy of formation of an element in its most stable state, under standard conditions, is
constant
changing
the same as the reverse process
infinity
zero
question 4 (1 point)

Explanation:

The standard enthalpy of formation ($\Delta H_f^\circ$) is defined as the enthalpy change when one mole of a substance is formed from its constituent elements in their standard states. For an element in its most stable state (e.g., $O_2$ for oxygen, $C$ (graphite) for carbon), there is no change in composition when forming itself. So, the enthalpy change is zero.

Answer:

zero