(1) Standard state for gases:

- Temperature: 273.15 K (0 °C)

- Pressure: 1 atm (100 kPa)

- The standard state for gases is the state of a gas at a pressure of 1 atm and a temperature of 0 °C.

(2) Standard state for aqueous solutions:

- Temperature: 298.15 K (25 °C)

- Pressure: 1 atm (100 kPa)

- Concentration: 1 M

- The standard state for aqueous solutions is the state of a substance at a concentration of 1 M in an aqueous solution at a pressure of 1 atm and a temperature of 25 °C.