Question

For a particular reaction, ΔH = -111.4 kJ and ΔS = -25.0 J/K. Calculate ΔG for this reaction at 298 K. (in KJ).

Answer 1

The Gibbs free energy change (ΔG) for the reaction at 298 K is calculated using the formula ΔG = ΔH - TΔS, resulting in ΔG of -103.95 kJ, indicating the reaction is spontaneous at this temperature.

Step-by-step explanation:

To calculate the Gibbs free energy change (ΔG) for the reaction at 298 K, we use the formula ΔG = ΔH - TΔS, where ΔH is the change in enthalpy, T is the temperature in Kelvin, and ΔS is the change in entropy. In this problem, ΔH is given as -111.4 kJ and ΔS is -25.0 J/K. Note that we need to have consistent units for ΔH and ΔS, so ΔS needs to be converted to kJ by dividing it by 1000, making it -0.025 kJ/K.

Plugging the values into the equation:

ΔG = (-111.4 kJ) - (298 K * -0.025 kJ/K)

ΔG = -111.4 kJ + 7.45 kJ

ΔG = -103.95 kJ

Therefore, the Gibbs free energy change for the reaction at 298 K is -103.95 kJ. This negative value indicates that the reaction is spontaneous under standard conditions at 298 K.