A coffee-cup calorimeter initially contains 125 g water at 24.28C. Potassium bromide (10.5 g), also at 24.28C, is added to the w

Question

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A coffee-cup calorimeter initially contains 125 g water at 24.28C. Potassium bromide (10.5 g), also at 24.28C, is added to the w

ater, and after the KBr dissolves, the final temperature is 21.18C. Calculate the enthalpy change for dissolving the salt in J/g and kJ/mol. Assume that the specific heat capacity of the solution is 4.18 J/8C

Chemistry

1 answer:

iren2701 [21] · Answer 1 · 2022-01-08T07:48:39+03:00

Answer:

The solution is given below

Explanation:

Heat, q= mc∆T

q= 125g x 4.18 J/g∙°C x (21.18x- 24.28) °C

q= -1619.75J

NEGATIVE SIGN INDICATES THAT HEAT IS ABSORBED.

Enthalpy Change, ∆H = 1619.75 7/ 10.5 g

= 154.26 J/g

No. of moles of KBr = Mass of KBr/ Molecular Weight of KBr

=10.5g/119gmol-1

=0.088 mol

∆H= 1619.75 J/ 0.088 mol

= 18.41 kJ/mol