# How much heat is lost when a 640 g piece of copper cools from 375°C to 26°C?

May 7, 2017

$86486.4 J$ or $86.486 k J$

#### Explanation:

$E = m c \delta \theta$

$m$: mass (kg)
$\delta \theta$: change in temperature (°C)
$c$: specific heat capacity - the energy needed to heat $1$kg of a substance by 1°C.

specific heat capacity of copper $= 385 J$/$k g$/°C

the energy needed to heat $1$kg of copper by 1°C is lost if $1$kg of copper cools by 1°C.

therefore:

$E = m c \delta \theta$

$= 0.640 k g \cdot 385 J$/$k g$/°C * (375-26)°C

$= 0.640 k g \cdot 385 J$/$k g$/°C * 351°C

$86486.4 J$ or $86.486 k J$