# How much energy is required to melt 1.5 kg of lead?

Jun 6, 2017

$34.53$kJ

#### Explanation:

The enthalpy of fusion (energy need to change state from solid to liquid) of lead is 4.77 kJ/mol (so it takes 4.77 kJ to melt one mole of lead).
We need to find the number of moles ($n$) of lead in 1.5kg ($m$).

$n = \frac{m}{M}$
From periodic table, M=207.2g/mol
Therefore, $n = \frac{1500 g}{207.2 g . m o {l}^{-} 1}$
$n = 7.24$ moles
Energy $= 7.24$moles$\cdot 4.77 k J . m o {l}^{-} 1$
Energy $34.53$kJ