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For reaction, 2K((g))+L((g))rarr2M((g)),...

For reaction, `2K_((g))+L_((g))rarr2M_((g)),DeltaU^(@)=-"10.5 KJ and "DeltaS^(@)=-"44.1 J K"^(-1)`. Calculate `DeltaG^(@)` for the reaction and predict whether the reaction will be spontaneous or non-spontaneous?

A

`DeltaG=+"0.16 kJ, non-spontaneous"`

B

`DeltaG=-"0.16 kJ, spontaneous"`

C

`DeltaG=+"26.12 kJ, non-spontaneous"`

D

`DeltaG=-"26.12 kJ, spontaneous"`

Text Solution

AI Generated Solution

The correct Answer is:
To solve the problem, we need to calculate the standard Gibbs free energy change (ΔG°) for the reaction given the standard internal energy change (ΔU°) and the standard entropy change (ΔS°). ### Step-by-Step Solution: 1. **Identify Given Values:** - ΔU° = -10.5 kJ (standard internal energy change) - ΔS° = -44.1 J/K (standard entropy change) - Temperature (T) = 298 K (standard temperature) - R = 8.314 × 10^(-3) kJ/(K·mol) (gas constant) 2. **Calculate ΔN_g (Change in Moles of Gases):** - From the reaction: \[ 2K(g) + L(g) \rightarrow 2M(g) \] - Moles of products = 2 (from 2M) - Moles of reactants = 2 (from 2K) + 1 (from L) = 3 - Therefore, \[ ΔN_g = \text{moles of products} - \text{moles of reactants} = 2 - 3 = -1 \] 3. **Calculate ΔH° (Standard Enthalpy Change):** - Using the formula: \[ ΔH° = ΔU° + ΔN_g \cdot R \cdot T \] - Substitute the values: \[ ΔH° = -10.5 \text{ kJ} + (-1) \cdot (8.314 \times 10^{-3} \text{ kJ/(K·mol)}) \cdot (298 \text{ K}) \] - Calculate: \[ ΔH° = -10.5 \text{ kJ} - 2.477 \text{ kJ} \] \[ ΔH° = -12.977 \text{ kJ} \] - Round it to: \[ ΔH° \approx -12.98 \text{ kJ} \] 4. **Calculate ΔG° (Standard Gibbs Free Energy Change):** - Using the formula: \[ ΔG° = ΔH° - T \cdot ΔS° \] - Convert ΔS° from J/K to kJ/K: \[ ΔS° = -44.1 \text{ J/K} = -0.0441 \text{ kJ/K} \] - Substitute the values: \[ ΔG° = -12.98 \text{ kJ} - (298 \text{ K} \cdot -0.0441 \text{ kJ/K}) \] - Calculate: \[ ΔG° = -12.98 \text{ kJ} + 13.14 \text{ kJ} \] \[ ΔG° = 0.16 \text{ kJ} \] 5. **Determine Spontaneity:** - Since ΔG° = +0.16 kJ (which is greater than 0), the reaction is non-spontaneous. ### Final Answer: - ΔG° = +0.16 kJ - The reaction is non-spontaneous.

To solve the problem, we need to calculate the standard Gibbs free energy change (ΔG°) for the reaction given the standard internal energy change (ΔU°) and the standard entropy change (ΔS°). ### Step-by-Step Solution: 1. **Identify Given Values:** - ΔU° = -10.5 kJ (standard internal energy change) - ΔS° = -44.1 J/K (standard entropy change) - Temperature (T) = 298 K (standard temperature) ...
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