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2 years ago

What is the total amount of heat released when 94.0 g water at 80.0 °C cools to form ice at −30.0 °C?

Chemistry

1 answer:

Wewaii [24]2 years ago

6 0

Answer:

The total amount of heat released is 68.7 kJ

Explanation:

Given that:

mass of water = 94.0 g

moles of water = 94 / 18.02 = 5.216

80⁰C ------> 0⁰C --------> -30⁰C

Q1 = m Cp dT

= 94 x 4.184 x (0 - 80)

= -31463.68 J

= -31.43 kJ

Q2 = 6.01 x 10^3 x 5.216

= - 31348.16 J

= -31.35 kJ

Q3 = - 94 x 2.09 x 30

= - 5893.8 J

= -5.894 kJ

Total heat = Q1 + Q2 + Q3 = -31.43 kJ + (-31.35 kJ ) + (-5.894 kJ ) = -68.7 kJ

Total heat released = -68.7 kJ

Note that the "negative sign" simply indicates heat released, therefore no need to put it in the answer.

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