Multiple Choice QuestionsUnder isothermal condition, a gas at 300 K expands from 0.1 L to 0.25 L against a constant external pressure of 2 bar. The work done by the gas is:(Given that 1 L bar = 100 J)
5 kJ
25 J
30 J
-30 J
D.
-30 J
Wirr = -Pext ΔV
= -2bar × (0.25 -0.1)L
= -2 × 0.15 L- bar
= -0.30 L-bar
= -0.30 × 100J
= -30J
In which case change in entropy is negative?
Expansion of a gas at constant temperature
Sublimation of solid to gas
2H(g) → H2(g)
Evaporation of water
For the reaction,
A (g) + 2B (g) → 2C (g) + 3D (g)
the change of enthalpy at 27°C is 19 kcal. The value of E is
21.2 kcal
17.8 kcal
18.4 kcal
20.6 kcal
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