5.00 g of carbon were adiabatically burned to CO2 in a 2.00 kg copper calorimeter which contained 2.50 kg of water. The temperature increased by 14.1 °C.

Specific heats: copper, 0.385 J K⁻¹ g⁻¹; water, 4.184 J K⁻¹ g⁻¹.

a) Determine the heat of combustion of carbon ignoring any heat absorbed by the calorimeter.

b) Now determine the heat of combustion considering the heat absorbed by the calorimeter.

Question

Chemistry

Kaylin Russo

19 February, 09:30

5.00 g of carbon were adiabatically burned to CO2 in a 2.00 kg copper calorimeter which contained 2.50 kg of water. The temperature increased by 14.1 °C.

Specific heats: copper, 0.385 J K⁻¹ g⁻¹; water, 4.184 J K⁻¹ g⁻¹.

a) Determine the heat of combustion of carbon ignoring any heat absorbed by the calorimeter.

b) Now determine the heat of combustion considering the heat absorbed by the calorimeter.

+3

Answers (1)

Know the Answer?

Dominguez · Answer 1

A. - 163.96kJ

B. - 158.34kJ

Explanation:

Heat of combustion is the heat released when an element with oxygen at stp.

Reaction for the combustion of carbon:

C (s) + O2 (g) - -> CO2 (g)

Enthalpy heat of combustion, C (using Hess law) = - 393.5 kJ/mol

m = 5g

Molecular weight = 12 g/mol

No of moles = mass/molecular weight

= 5/12

= 0.417mol

DH = - 393.5 * 0.417

= - 163.96 kJ

B. Heat absorbed by the calorimeter = heat evolve by combustion

= mCH2ODT + mCcDT

Where CH2O is the specific heat capacity of the water in the calorimeter

Cc is the specific heat capacity of copper calorimeter

= (2500*4.184*14.1) + (2000*0.385*14.1)

= - 158343J

= - 158.34kJ