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the enthalpy of vaporisation of a substance is 840
Question:
The enthalpy of vaporisation of a substance is
8400
J
m
o
l
−
1
and its boiling point is
−
173.15
∘
C
. The entropy change for vaporisation is:
JEE Main
Updated On:
Sep 30, 2024
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Correct Answer:
84
Solution and Explanation
Explanation:
Given: Enthalpy of vaporisation of a substance is:
8400
J
m
o
l
−
1
Temperature or boiling point of substance is:
−
173.15
∘
C
We have temperature in Kelvin,
=
Celsius temperature
+
273.15
∘
C
=
−
173.15
∘
C
+
273.15
∘
C
=
100
K
Now, we know,Change in entropy,
Δ
S
=
q
r
e
v
T
=
(
8400
100
)
=
84
J
m
o
l
−
1
K
−
1
Hence, the correct answer is '84'.
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