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JEE Main 20202 SeptemberEvening Shift
Exam
JEE Main
Year
2020
Date
2 September
Shift
Evening Shift
Subject
Chemistry
Chapter
Thermodynamics (C)

JEE Main 2020 · 2 September · Evening Shift · Chemistry · Thermodynamics (C)

The heat of combustion of ethanol into carbon dioxides and water is...

The heat of combustion of ethanol into carbon dioxides and water is −327- 327 Kcal at constant pressure. The heat evolved (in cal) at constant volume at 27°C27 ° C (if all gases behave ideally) is \left(R = 2{calmol}^{- 1}{K}^{- 1}\right)$________

Correct answer

0

Step-by-step solution

C2H5OH(ℓ)+O2(g)⟶2O2(g)+3H2O(ℓ);ΔHC=−327Kcal{C}_{2}{H}_{5}OH ( ℓ ) + {O}_{2} ( g ) ⟶ 2{O}_{2} ( g ) + 3{H}_{2}O ( ℓ ) ; \Delta{H}_{C} = - 327Kcal
\DeltaHc=ΔUC+ΔngRT\DeltaHc = \Delta{U}_{C} + \Delta{n}_{g}RT
−327×103=ΔUC+1×2×300- 327 \times {10}^{3} = \Delta{U}_{C} + 1 \times 2 \times 300
ΔUC=−326400cal\Delta{U}_{C} = - 326400cal

So heat evolved as constant volume is 326400326400cal

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