273 K acetone 23.0 g 329 K vapor
acetone CH3COCH3 mp 178 K bp 329 K 273 K 23.0 g 329 K vapor
Acetone CH3COCH3, is a common organic solvent
with relatively low melting point (178 K) and boiling point (329 K).
The enthalpy of fusion of acetone is 5.72 kJ/mol,
and its enthalpy of vaporization is 29.1 kJ/mol.
The specific heats of solid and liquid acetone
are 96 J/mol-K and 125.5 J/mol-K respectively.
(a) How much heat is required to convert
23.0 g of acetone at 273 K to the vapor phase at 329 K?
(b) How much heat is required to convert
the same amount of acetone at 77 K to the vapor phase at 329 K?
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▶ 참고: 열용량과 비열
[ https://ywpop.tistory.com/2897 ]
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CH3COCH3의 몰질량 = 58.08 g/mol 이므로,
23.0 g / (58.08 g/mol) = 0.396 mol 아세톤
( 참고 https://ywpop.tistory.com/7738 )
(a) How much heat is required to convert
23.0 g of acetone at 273 K to the vapor phase at 329 K?
[1] 273 K 액체 아세톤을 329 K 액체 아세톤으로 바꾸는데 필요한 열
q = C m Δt
= (125.5 J/mol-K) (0.396 mol) (329 – 273 K)
= 2783.088 J
[2] 329 K 액체 아세톤을 329 K 증기 아세톤으로 바꾸는데 필요한 열
q = C m
= (29100 J/mol) (0.396 mol)
= 11523.6 J
[1] + [2]
= 2783.088 + 11523.6 = 14306.688 J
답: 14.3 kJ
[ 관련 예제 https://ywpop.tistory.com/19777 ] –10℃ 얼음 100 mol을 120℃ 수증기로
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