Engage with knowledgeable experts and get accurate answers on IDNLearn.com. Our platform is designed to provide reliable and thorough answers to all your questions, no matter the topic.

None of these is correct.

At 298 K, the combustion of methane [tex]$\left( CH _4\right)$[/tex] produces an enthalpy change of [tex]$-890.3 \frac{kJ}{mol}$[/tex] and an entropy change of [tex]$-242 \frac{J}{\text{mol} \cdot K}$[/tex]. What is [tex]$\Delta G^{\circ}$[/tex]?


Sagot :

Sure! Let's solve the problem step by step.

Given:
- Enthalpy change: [tex]\(\Delta H = -890.3 \, \text{kJ/mol}\)[/tex]
- Entropy change: [tex]\(\Delta S = -242 \, \text{J/(mol⋅K)}\)[/tex]
- Temperature: [tex]\(T = 298 \, \text{K}\)[/tex]

We need to find the Gibbs free energy change, which is given by the equation:
[tex]\[ \Delta G = \Delta H - T \Delta S \][/tex]

However, notice that the enthalpy change ([tex]\(\Delta H\)[/tex]) is given in [tex]\(\text{kJ/mol}\)[/tex] while the entropy change ([tex]\(\Delta S\)[/tex]) is given in [tex]\(\text{J/(mol⋅K)}\)[/tex]. We need to convert the entropy change from [tex]\(\text{J/(mol⋅K)}\)[/tex] to [tex]\(\text{kJ/(mol⋅K)}\)[/tex] to match the units of enthalpy change.

1. Convert entropy change to [tex]\(\text{kJ/(mol⋅K)}\)[/tex]:
[tex]\[ \Delta S = -242 \, \text{J/(mol⋅K)} \times \frac{1 \, \text{kJ}}{1000 \, \text{J}} = -0.242 \, \text{kJ/(mol⋅K)} \][/tex]

2. Now, we can calculate [tex]\(\Delta G\)[/tex] using the formula:
[tex]\[ \Delta G = \Delta H - T \Delta S \][/tex]

Substitute the values into the equation:
[tex]\[ \Delta G = -890.3 \, \text{kJ/mol} - 298 \, \text{K} \times (-0.242 \, \text{kJ/(mol⋅K)}) \][/tex]

3. Perform the multiplication first:
[tex]\[ 298 \, \text{K} \times (-0.242 \, \text{kJ/(mol⋅K)}) = -72.116 \, \text{kJ/mol} \][/tex]

4. Substitute this value back into the equation:
[tex]\[ \Delta G = -890.3 \, \text{kJ/mol} + 72.116 \, \text{kJ/mol} \][/tex]

5. Finally, sum the values:
[tex]\[ \Delta G = -818.184 \, \text{kJ/mol} \][/tex]

So, the Gibbs free energy change [tex]\(\Delta G\)[/tex] is [tex]\(-818.184 \, \text{kJ/mol}\)[/tex].
We appreciate every question and answer you provide. Keep engaging and finding the best solutions. This community is the perfect place to learn and grow together. Your questions deserve reliable answers. Thanks for visiting IDNLearn.com, and see you again soon for more helpful information.