Agas is inside a cylinder fitted with a piston. the gas and its surroundings are both at 20 ∘c and the gas is compressed as the piston moves and decreases the cylinder volume. the compression takes place slowly enough to allow the gas temperature to stay at 20 ∘c and the work done on the gas by the compression is 1.9 × 103 j. what is the change in entropy of the gas

-  6.48 J K⁻¹

Explanation:

Temperature of gas = 20°C

= 273 +20 = 293 K.

As temperature is fixed , there will be no change in gas internal energy

Δ E = 0

From the relation

Δ Q =  Δ E+ Δ W

Work done on the gas is 1.9 x 10³

Δ W = - 1.9 x 10³ J

Δ Q = - 1.9 x 10³ J

Δ S =  Δ Q / T

=

= -  6.48 J K⁻¹

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