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Thermodynamics and Thermochemistry
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Gibbs energy, spontaneity and relation to equilibrium constant
JEE Main level
Numerical answer
Difficulty 2 of 3
td100
For
A
B
at
300
K
,
Δ
G
∘
=
+
5.00
kJ
mo
l
−
1
. Find
Δ
G
in
kJ
mo
l
−
1
(two decimals) when the reaction quotient is
Q
=
0.0100
. Use
R
=
8.314
J
mo
l
−
1
K
−
1
.
Numerical answer type, answer in kJ/mol, tolerance 0.01.
Answer: -6.4862 kJ/mol
Δ
G
=
Δ
G
∘
+
RT
ln
Q
=
5000
+
8.314
×
300
×
ln
(
0.0100
)
=
5000
−
11486
J
=
−
6.49
kJ
mo
l
−
1
. It is negative, so the forward reaction is spontaneous at this composition.
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