Discover the answers you need at Westonci.ca, a dynamic Q&A platform where knowledge is shared freely by a community of experts. Discover a wealth of knowledge from professionals across various disciplines on our user-friendly Q&A platform. Connect with a community of professionals ready to help you find accurate solutions to your questions quickly and efficiently.
Sagot :
To determine at which temperature the reaction is spontaneous, we need to calculate the Gibbs free energy change ([tex]\(\Delta G\)[/tex]) for each temperature given in the choices. The Gibbs free energy change can be calculated using the formula:
[tex]\[ \Delta G = \Delta H - T \Delta S \][/tex]
where:
- [tex]\(\Delta H\)[/tex] is the enthalpy change of the reaction.
- [tex]\(T\)[/tex] is the temperature in Kelvin.
- [tex]\(\Delta S\)[/tex] is the entropy change of the reaction.
Given:
- [tex]\(\Delta H = -92 \)[/tex] kJ/mol
- [tex]\(\Delta S = -0.199 \)[/tex] kJ/(mol·K)
We need to evaluate [tex]\(\Delta G\)[/tex] for each of the following temperatures: [tex]\(500 K\)[/tex], [tex]\(400 K\)[/tex], [tex]\(700 K\)[/tex], and [tex]\(600 K\)[/tex].
1. At [tex]\(500 K\)[/tex]:
[tex]\[ \Delta G = -92 - (500 \times -0.199) \][/tex]
[tex]\[ \Delta G = -92 + 99.5 \][/tex]
[tex]\[ \Delta G = 7.5 \text{ kJ/mol} \][/tex]
2. At [tex]\(400 K\)[/tex]:
[tex]\[ \Delta G = -92 - (400 \times -0.199) \][/tex]
[tex]\[ \Delta G = -92 + 79.6 \][/tex]
[tex]\[ \Delta G = -12.4 \text{ kJ/mol} \][/tex]
3. At [tex]\(700 K\)[/tex]:
[tex]\[ \Delta G = -92 - (700 \times -0.199) \][/tex]
[tex]\[ \Delta G = -92 + 139.3 \][/tex]
[tex]\[ \Delta G = 47.3 \text{ kJ/mol} \][/tex]
4. At [tex]\(600 K\)[/tex]:
[tex]\[ \Delta G = -92 - (600 \times -0.199) \][/tex]
[tex]\[ \Delta G = -92 + 119.4 \][/tex]
[tex]\[ \Delta G = 27.4 \text{ kJ/mol} \][/tex]
A reaction is spontaneous when [tex]\(\Delta G\)[/tex] is less than zero (i.e., [tex]\(\Delta G < 0\)[/tex]).
From our calculations:
- At [tex]\(500 K\)[/tex], [tex]\(\Delta G = 7.5\)[/tex] kJ/mol (not spontaneous).
- At [tex]\(400 K\)[/tex], [tex]\(\Delta G = -12.4\)[/tex] kJ/mol (spontaneous).
- At [tex]\(700 K\)[/tex], [tex]\(\Delta G = 47.3\)[/tex] kJ/mol (not spontaneous).
- At [tex]\(600 K\)[/tex], [tex]\(\Delta G = 27.4\)[/tex] kJ/mol (not spontaneous).
Therefore, the reaction is only spontaneous at [tex]\(400 K\)[/tex].
Thus, the correct answer is:
B. [tex]\[400 K\][/tex]
[tex]\[ \Delta G = \Delta H - T \Delta S \][/tex]
where:
- [tex]\(\Delta H\)[/tex] is the enthalpy change of the reaction.
- [tex]\(T\)[/tex] is the temperature in Kelvin.
- [tex]\(\Delta S\)[/tex] is the entropy change of the reaction.
Given:
- [tex]\(\Delta H = -92 \)[/tex] kJ/mol
- [tex]\(\Delta S = -0.199 \)[/tex] kJ/(mol·K)
We need to evaluate [tex]\(\Delta G\)[/tex] for each of the following temperatures: [tex]\(500 K\)[/tex], [tex]\(400 K\)[/tex], [tex]\(700 K\)[/tex], and [tex]\(600 K\)[/tex].
1. At [tex]\(500 K\)[/tex]:
[tex]\[ \Delta G = -92 - (500 \times -0.199) \][/tex]
[tex]\[ \Delta G = -92 + 99.5 \][/tex]
[tex]\[ \Delta G = 7.5 \text{ kJ/mol} \][/tex]
2. At [tex]\(400 K\)[/tex]:
[tex]\[ \Delta G = -92 - (400 \times -0.199) \][/tex]
[tex]\[ \Delta G = -92 + 79.6 \][/tex]
[tex]\[ \Delta G = -12.4 \text{ kJ/mol} \][/tex]
3. At [tex]\(700 K\)[/tex]:
[tex]\[ \Delta G = -92 - (700 \times -0.199) \][/tex]
[tex]\[ \Delta G = -92 + 139.3 \][/tex]
[tex]\[ \Delta G = 47.3 \text{ kJ/mol} \][/tex]
4. At [tex]\(600 K\)[/tex]:
[tex]\[ \Delta G = -92 - (600 \times -0.199) \][/tex]
[tex]\[ \Delta G = -92 + 119.4 \][/tex]
[tex]\[ \Delta G = 27.4 \text{ kJ/mol} \][/tex]
A reaction is spontaneous when [tex]\(\Delta G\)[/tex] is less than zero (i.e., [tex]\(\Delta G < 0\)[/tex]).
From our calculations:
- At [tex]\(500 K\)[/tex], [tex]\(\Delta G = 7.5\)[/tex] kJ/mol (not spontaneous).
- At [tex]\(400 K\)[/tex], [tex]\(\Delta G = -12.4\)[/tex] kJ/mol (spontaneous).
- At [tex]\(700 K\)[/tex], [tex]\(\Delta G = 47.3\)[/tex] kJ/mol (not spontaneous).
- At [tex]\(600 K\)[/tex], [tex]\(\Delta G = 27.4\)[/tex] kJ/mol (not spontaneous).
Therefore, the reaction is only spontaneous at [tex]\(400 K\)[/tex].
Thus, the correct answer is:
B. [tex]\[400 K\][/tex]
Thanks for using our service. We aim to provide the most accurate answers for all your queries. Visit us again for more insights. Thank you for your visit. We're committed to providing you with the best information available. Return anytime for more. We're glad you chose Westonci.ca. Revisit us for updated answers from our knowledgeable team.