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Tom [10]
3 years ago
6

When a 7.00 g7.00 g sample of KBrKBr is dissolved in water in a calorimeter that has a total heat capacity of 2.72 kJ⋅K−1,2.72 k

J⋅K−1, the temperature decreases by 0.430 K.0.430 K. Calculate the molar heat of solution of KBr.
Chemistry
1 answer:
algol133 years ago
4 0

Answer : The molar heat of solution of KBr is 19.9 kJ/mol

Explanation :

Mass of KBr = 7.00 g

Molar mass of KBr = 119 g/mole

Heat capacity = 2.72 kJ/K

Change in temperature = 0.430 K

First we have to calculate the moles of KBr.

\text{ Moles of }KBr=\frac{\text{ Mass of }KBr}{\text{ Molar mass of }KBr}=\frac{7.00g}{119g/mole}=0.0588moles

Now we have to calculate the heat of the reaction.

q=c\times \Delta T

where,

q = amount of heat = ?

c = heat capacity = 2.72kJ/K

\Delta T = change in temperature = 0.430 K

Now put all the given values in the above formula, we get:

q=2.72kJ/K\times 0.430K

q=1.17kJ

Now we have to calculate the molar heat of solution of KBr.

\text{Molar heat of solution of }KBr=\frac{q}{n}

where,

n = number of moles of KBr

\text{Molar heat of solution of }KBr=\frac{1.17kJ}{0.0588moles}=19.9kJ/mol

Therefore, the molar heat of solution of KBr is 19.9 kJ/mol

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