Question

A 1.250-g sample of benzoic acid, C7H6O2, was placed in a combustion bomb. The bomb was filled with an excess of oxygen at high pressure, sealed, and immersed in a pail of water which served as a calorimeter. The heat capacity of the entire apparatus (bomb, pail, thermometer, and water) was found to be 10.134 kJ/K. The oxidation of the benzoic acid was triggered by passing an electric spark through the sample. After complete combustion, the thermometer immersed in the water registered a temperature 3.256 K greater than before the combustion. What is DEcombustion per mole of benzoic acid burned

Answer 1

Answer:

3224 kJ/mol

Explanation:

The combustion of benzoic acid occurs as follows:

C₇H₆O₂ + 13/2O₂ → 7CO₂ + 3H₂O + dE

The change in temperature in the reaction is the change due the energy released, that is:

3.256K * (10.134kJ / K) = 33.00kJ are released when 1.250g reacts

To find the heat released per mole we have to find the moles of benzoic acid:

Moles benzoic acid -Molar mass: 122.12g/mol-:

1.250g * (1mol / 122.12g) = 0.0102 moles

The dE combustion per mole of benzoic acid is:

33.00kJ / 0.0102moles =

3224 kJ/mol