When a log burns in a fire, a a physical change has occurred. b mass is gained. c new substances are formed.
2 answers:
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Question:
Part D) An object at 20∘C absorbs 25.0 J of heat. What is the change in entropy ΔS of the object? Express your answer numerically in joules per kelvin.
Part E) An object at 500 K dissipates 25.0 kJ of heat into the surroundings. What is the change in entropy ΔS of the object? Assume that the temperature of the object does not change appreciably in the process. Express your answer numerically in joules per kelvin.
Part F) An object at 400 K absorbs 25.0 kJ of heat from the surroundings. What is the change in entropy ΔS of the object? Assume that the temperature of the object does not change appreciably in the process. Express your answer numerically in joules per kelvin.
Part G) Two objects form a closed system. One object, which is at 400 K, absorbs 25.0 kJ of heat from the other object,which is at 500 K. What is the net change in entropy ΔSsys of the system? Assume that the temperatures of the objects do not change appreciably in the process. Express your answer numerically in joules per kelvin.
Answer:
D) 85 J/K
E) - 50 J/K
F) 62.5 J/K
G) 12.5 J/K
Explanation:
Let's make use of the entropy equation: ΔS =
Part D)
Given:
T = 20°C = 20 +273 = 293K
Q = 25.0 kJ
Entropy change will be:
ΔS =
= 85 J/K
Part E)
Given:
T = 500K
Q = -25.0 kJ
Entropy change will be:
ΔS =
= - 50 J/K
Part F)
Given:
T = 400K
Q = 25.0 kJ
Entropy change will be:
ΔS =
= 62.5 J/K
Part G:
Given:
T1 = 400K
T2 = 500K
Q = 25.0 kJ
The net entropy change will be:
ΔS =
= 12.5 J/K
Explanation:
The given data is as follows.
T = 298 K, = -5645 kJ/mol
= -5798 kJ/mol
Relation between and
are as follows.
=
-5798 kJ/mol = -5645 kJ/mol -
-153 kJ/mol = -
= 0.513 kJ/mol K
Now, temperature is = (37 + 273) K = 310 K
Since, =
=
= (-5645 kJ/mol - 159.03 kJ/mol)
= -5804.03 kJ/mol
As, change in Gibb's free energy = maximum non-expansion work
= -5804.03 kJ/mol - (-5798 kJ/mol)
= -6.03 kJ/mol
Therefore, we can conclude that the additional non-expansion work is -6.03 kJ/mol.