Question

How much energy is needed to melt 25.4 grams of I2?

Answer 1

Answer : The energy needed to melt 25.4 grams of $I_2$ is, $1.57\times 10^{3}J$

Explanation : Given,

Mass of $I_2$ = 25.4 g

$H_{fus}$ = 61.7 J/g

As, 1 gram of $I_2$ melt to needed energy = 61.7 J

So, 25.4 gram of $I_2$ melt to needed energy = $25.4\times 61.7=1567.18J=1.57\times 10^{3}J$

Therefore, the energy needed to melt 25.4 grams of $I_2$ is, $1.57\times 10^{3}J$

Answer 2

We know the equation of latent heat:

Q = mL

(Energy = mass * latent heat)

Therefore, this problem is a regular application of this:

Q = 25.4 * 61.7

Q = 1567,18

With the 3 digits:

Q = 1570 J