CameraIcon

SearchIcon

MyQuestionIcon

217

You visited us 217 times! Enjoying our articles? Unlock Full Access!

Entropy

Two blocks of...

Question

Two blocks of the same metal having same mass and at temperature $T_{1}$ and $T_{2}$ respectively, are brought in contact with each other and allowed to attain thermal equilibrium at constant pressure. The change in entropy, $△ S$ for this process is

A

2 C_{p} l n [\frac{T_{1} + T_{2}}{2 T_{1} T_{2}}]

No worries! We‘ve got your back. Try BYJU‘S free classes today!

B

C_{p} l n [\frac{(T_{1} + T_{2})^{2}}{4 T_{1} T_{2}}]

Right on! Give the BNAT exam to get a 100% scholarship for BYJUS courses

C

2 C_{p} l n [\frac{(T_{1} + T_{2})^{2}}{4 T_{1} T_{2}}]

No worries! We‘ve got your back. Try BYJU‘S free classes today!

D

2 C_{p} l n ⎡ ⎢ ⎢ ⎢ ⎢ ⎣ \frac{(T_{1} + T_{2})^{\frac{1}{2}}}{4 T_{1} T_{2}} ⎤ ⎥ ⎥ ⎥ ⎥ ⎦

No worries! We‘ve got your back. Try BYJU‘S free classes today!

Open in App

Solution

The correct option is B $C_{p} l n [\frac{(T_{1} + T_{2})^{2}}{4 T_{1} T_{2}}]$
As the two boxes are identical, So $C_{p}$ will be same for both and
$T_{f i n a l} = \frac{T_{1} + T_{2}}{2}$

Entropy change in the first box will be given by
$△ S_{1} = C_{p} l n \frac{T_{f}}{T_{i}} s i n c e, T_{i} = T_{1} △ S_{1} = C_{p} l n \frac{T_{f}}{T_{1}}$

Entropy change in the second box will be given by
$△ S_{2} = C_{p} l n \frac{T_{f}}{T_{i}} s i n c e, T_{i} = T_{2} △ S_{2} = C_{p} l n \frac{T_{f}}{T_{2}}$

Total entropy change will be given by addition of above two.
$△ S = △ S_{1} + △ S_{2} = C_{p} l n \frac{T_{f}^{2}}{T_{1} T_{2}}$
putting the value of $T_{f}$
$△ S = C_{p} l n [\frac{(T_{1} + T_{2})^{2}}{4 T_{1} T_{2}}]$

Suggest Corrections

thumbs-up

36

Similar questions

Q. Two blocks of the same metal having same mass and at temperature

T_{1}

T_{2}

respectively, are brought in contact with each other and allowed to attain thermal equilibrium at constant pressure. The change in entropy,

△ S

for this process is

Q. Two blocks of the same metal having the same mass and at temperature

T_{1}

T_{2}

, respectively. are brought in contact with each other and allowed to attain thermal equilibrium at constant pressure. The change in entropy,

Δ S

, for this process is :

Q. Two blocks of the same metal having same mass and at temperature

T_{1}

T_{2}

respectively, are bought in contact with each other and allowed to attain thermal equilibrium at constant pressure. The change in entropy,

Δ S

for this process is

Q. Two bodies B and C with intial temperatures

T_{1} a n d

T_{2}

are brought in contact. Temperature at thermal equilibrium is

T

T_{2} >

T_{1}

Q. For a reaction,

A ⇌ P

[A]

[P]

with time at temperature

T_{1}

T_{2}

are given below.
If

T_{2} > T_{1}

, the correct statement(s) is/are:
(Assume

△ H^{θ}

△ S^{θ}

are independent of temperature and ratio of

l n K

T_{1}

l n K

T_{2}

is greater than

\frac{T_{2}}{T_{1}}

H, S, G

K

are enthalpy, entropy, Gibbs energy and equilibrium constant, respectively.)

View More

Join BYJU'S Learning Program

explore_more_icon

Explore more

Standard XII Chemistry

Join BYJU'S Learning Program

CrossIcon