Br2(l) boiling point 58.8℃ ΔH_vap 29.6 kJ/mol entropy

Br2(l) boiling point 58.8℃ ΔH_vap 29.6 kJ/mol entropy

 

 

The normal boiling point of Br2(l) is 58.8℃,

and its molar enthalpy of vaporization is ΔH_vap = 29.6 kJ/mol.

 

a) When Br2(l) boils at its normal boiling point,

does its entropy increase or decrease?

 

b) Calculate the value of ΔS

when 1.00 mol of Br2(l) is vaporized at 58.8℃.

ΔS = (answer in J/K)

 

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▶ 참고: 상변화에 따른 엔트로피 [ https://ywpop.tistory.com/10703 ]

▶ 참고: 물의 상변화에 따른 ΔS [ https://ywpop.tistory.com/3040 ]

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b) Calculate the value of ΔS

when 1.00 mol of Br2(l) is vaporized at 58.8℃.

ΔS = (answer in J/K)

 

Br2(l) ⇌ Br2(g) ... ΔH_vap = 29.6 kJ/mol

 

 

 

ΔS = q_rev / T = ΔH / T

( 참고 https://ywpop.tistory.com/10308 )

 

ΔH = (29.6 kJ/mol) (1.00 mol) = 29.6 kJ

 

ΔS = 29600 J / (273 + 58.8 K) = 89.2 J/K

 

 

 

 

또는

ΔG = ΔH – TΔS

( 참고 https://ywpop.tistory.com/7438 )

 

상변화(상평형) 시, ΔG = 0

 

ΔH = TΔS

 

ΔS = ΔH / T

= 29600 J / (273 + 58.8 K)

= 89.2 J/K