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.

Question

Chemistry

Danica Daugherty

30 September, 04:35

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.

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Answers (1)

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Rapunzel · Answer 1

-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

dа ta:

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