Mechanical Engineering - Thermodynamics - Discussion

Discussion Forum : Thermodynamics - Section 2 (Q.No. 13)
13.
The entropy of water at 0°C is assumed to be
1
0
-1
10
Answer: Option
Explanation:
No answer description is available. Let's discuss.
Discussion:
27 comments Page 1 of 3.

Muhammed aslam said:   7 years ago
Actually, entropy has some value at 0 degree centigarade. We cannot achieve zero entropy (according to 3rd law). But for ease of calculation we assume entropy is zero for water at zero degree celcius. Steam table is based on this concept. However absolute value of entropy or enthalpy is not important at all. Always we consider change in entropy on process.

Sweta said:   8 years ago
Obviously, it is 0K as at this temperature the molecular momentum is zero. Even during calculation, we don't use celsius.

Some of you said q=0.
How is q=0 as we have still latent heat of vapourisation?

Sohan said:   6 years ago
For 0K, entropy is zero for perfectly crystalline substance, but 0 K is unachieveable and absolute entropy is not measurable, hence we take triple point of water arbitrarily as 0 entropy.

Vilas s h said:   6 years ago
At 0°c water will freeze but a moment of particles are there when particles are moving how the entropy is zero. At 0k there is no particles movement, means no moment zero entropy.

Aditya loachab said:   6 years ago
According to the third law of thermodynamics, entropy remains until temperature 0K because some molecular momentum is there till 0Kelvin.

Bishwadeep Pal said:   8 years ago
Entropy means randomness. At 0 degree C water freezes and thus molecules don't moive. Hence entropy will be equal to 0.

Akash said:   8 years ago
When 0k Entropy is 0 but it only applicable for pure crystal substance so water is not pure Crystalline substance.

Marwa said:   9 years ago
What is the final answer I agree with the latest answer 0 degree C mean 273 k. So it has answer value.

Shahid said:   7 years ago
Entropy should be zero at 0° K, but in case of water 0 entropy is assumed at 0° celcius.

Shivam gohite said:   1 decade ago
At 0k, value of entropy is zero. At 0 degC entropy depends on the direction of heat transfer.


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