When a 3.00 g 3.00 g sample of KBr KBr is dissolved in water in a calorimeter that has a total heat capacity of 1.36 kJ ⋅ K - 1, 1.36 kJ⋅K-1, the temperature decreases by 0.370 K. 0.370 K. Calculate the molar heat of solution of KBr. KBr.

Question

Davin Burgess

Chemistry

28 January, 18:17

When a 3.00 g 3.00 g sample of KBr KBr is dissolved in water in a calorimeter that has a total heat capacity of 1.36 kJ ⋅ K - 1, 1.36 kJ⋅K-1, the temperature decreases by 0.370 K. 0.370 K. Calculate the molar heat of solution of KBr. KBr.

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Answers (1)

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Kristopher · Answer 1

Molar heat of solution of KBr is 20.0kJ/mol

Explanation:

Molar heat of solution is defined as the energy released (negative) or absorbed (Positive) per mole of solute being dissolved in solvent.

The dissolution of KBr is:

KBr → K⁺ + Br⁻

In the calorimeter, the temperature decreases 0.370K, that means the solution absorbes energy in this process. The energy is:

q = 1.36kJK⁻¹ * 0.370K

q = 0.5032kJ

Moles of KBr in 3.00g are:

3.00g * (1mol / 119g) = 0.0252moles

Thus, molar heat of solution of KBr is:

0.5032kJ / 0.0252moles = 20.0kJ/mol