Question

How much energy is needed to melt a 100-g sample of aluminum whose initial temperature is 20 degrees celcius.

Answer 1

Solution.

$m=0.1kg;$

$t_0=20^oC;$

$t=660^oC;$

$\lambda=390\sdot10^3J/kg;$

$c=920J/{kg^oC};$

$Q=cm\Delta t+\lambda m;$

$Q=920\sdot0.1\sdot(660-20)+390\sdot10^3\sdot0.1=97880J;$

Answer: $Q=97880J.$