A) i) State Hess's law. ii) State the standard conditions for enthalpy measurement.

a) i) State Hess's law.
Hess's Law states that the enthalpy change of a chemical reaction is independent of the path taken between the initial and final states, provided the initial and final conditions are the same.

a) ii) State the standard conditions for enthalpy measurement.
The standard conditions for enthalpy measurement are:

• Temperature: $298 \text{ K}$ ($25^\circ\text{C}$)
• Pressure: $1 \text{ atm}$ ($101.325 \text{ kPa}$ or $1 \text{ bar}$)
• Concentration: $1 \text{ M}$ for solutions
• Physical state: All