How much heat is lost when 575 g of molten iron at 1825 K becomes solid at 1181 K and cools to 293 K?

Question

Layne

Chemistry

29 September, 23:08

How much heat is lost when 575 g of molten iron at 1825 K becomes solid at 1181 K and cools to 293 K?

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Answers (1)

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Albert Macias · Answer 1

Answer is: - 963,8 kJ.

Q₁ = m (Fe) · C · ΔT₁.

C - specific heat capacity of liquid iron, C (Fe) = 0,82 J/g° C.

m (Fe) = 575 g.

ΔT₁ = 1181 - 1825 = - 644°C.

Q₁ = - 859306,5 J = - 859,3 kJ.

Q₂ = m (Fe) · C · ΔT₂.

ΔT₂ = 293 - 1181 = - 888°C.

C - specific heat capacity, C (Fe) = 0,44 J/g°C.

Q₂ = - 224664 J = - 224,66 kJ.

Q₃ = - heat of fusion, ΔH = 209 J/g.

Q₃ = 120175 J = 120,17 kJ.

Q = Q₁ + Q₂ + Q₃ = - 963,8 kJ.