C10H8 1.435 g 20.28℃ 25.95℃ 10.17 kJ/℃

C10H8 1.435 g 20.28℃ 25.95℃ 10.17 kJ/℃

 

 

A quantity of 1.435 g of naphthalene (C10H8),

a pungent-smelling substance used in moth repellents,

was burned in a constant-volume bomb calorimeter.

Consequently, the temperature of the water

rose from 20.28℃ to 25.95℃.

If the heat capacity of the bomb plus water was 10.17 kJ/℃,

calculate the heat of combustion of naphthalene on a molar basis;

that is, find the molar heat of combustion.

 

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C = q / Δt 이므로,

( 참고 https://ywpop.tistory.com/2897 )

 

q = C Δt

= (10.17 kJ/℃) (25.95 – 20.28 ℃)

= 57.6639 kJ

---> 주위가 흡수한 열

---> 계가 방출한 열 = –57.6639 kJ

 

 

 

C10H8의 몰질량 = 10(12) + 8(1) = 128 g/mol 이므로,

1.435 g / (128 g/mol) = 0.0112109 mol

 

 

 

몰당 연소열을 계산하면,

–57.6639 kJ / 0.0112109 mol

= –5144 kJ/mol

 

 

 

답: –5.144×10^3 kJ/mol

 

 

 

 

[참고] C10H8의 몰질량 = 128.17 g/mol

(–(10.17) (25.95 – 20.28)) / (1.435 / 128.17)

= –5150.37 kJ/mol

 

 

 

 

[키워드] C10H8의 몰당 연소열 기준문서