How much heat is liberated (in kJ) from 249 g of silver when it cools from 87 °C to 26 °C? The heat capacity of silver is 0.235 Jg^{-1} °C^{-1}. Note, "heat liberated" implies that the change in heat is negative. Enter a positive number.

Question

Finnegan

Chemistry

1 June, 10:52

How much heat is liberated (in kJ) from 249 g of silver when it cools from 87 °C to 26 °C? The heat capacity of silver is 0.235 Jg^{-1} °C^{-1}. Note, "heat liberated" implies that the change in heat is negative. Enter a positive number.

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Answers (1)

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Averie · Answer 1

q = - 3.569KJ 0r 3.569KJ Liberated heat (signifying the change in heat is negative)

Explanation:

liberated heat implies that change in heat is negative, therefore

q = - m c ΔT

where, m = mass of the Silver = 249 g

c = specific heat capacity of Silver = 0.235 Jg^{-1} °C^{-1

ΔT = change in temperature = 87°C - 26 °C = 61°C

q = - m x c x ΔT

= - 249 x 0.235 x 61 = - 3569.415J rounded to - 3569J

Changing to KJ becomes = - 3569/1000 = - 3.569 KJ

q = - 3.569KJ 0r 3.569KJ liberated heat.