Question

A 0.1375-g sample of solid magnesium is burned in a constant-volume bomb calorimeter that has a heat capacity of 3024 J/°C. The temperature increases by 1.126°C. Calculate the heat given off by the burning Mg, in kJ/g and in kJ/mol.

Answer 1

Answer:

-24.76 kJ/g; -601.8 kJ/mol

Explanation:

There are two heat flows in this experiment.

Heat from reaction + heat absorbed by calorimeter = 0

             q1                +                     q2                         = 0

           mΔH             +                    CΔT                        = 0

Data:

m = 0.1375 g

C = 3024 J/°C

ΔT = 1.126 °C

Calculations:

0.1375ΔH + 3024 × 1.126 = 0

           0.1375ΔH + 3405 = 0

                        0.1375ΔH = -3405

                                   ΔH = -24 760 J/g = -24.76 kJ/g

ΔH = -24.76 kJ/g ×24.30 g/mol = -601.8 kJ/mol