Question

Calculate the specific latent heat of fusion of a solid if 25 g of it requires 8400 J of heat energy for melting.

• A. $3.36\times {10}^{5}J/kg$
• B. $4.36\times {10}^{5}J/kg$
• C. $6.36\times {10}^{5}J/kg$
• D. $5.36\times {10}^{5}J/kg$

Answer 1

The correct option is A $3.36\times {10}^{5}J/kg$

Mass of the solid $=25g$
Energy required for melting it completely $=8400J$
Latent heat of fusion is the amount of heat energy required for melting one unit mass of a substance.
Here, unit mass $=1g$
So, specific latent heat of fusion $=8400/25=336J/g$
Specific latent heat of fusion is $336J/g$.
In SI units, specific heat is calculated as $J/kg$.
So, for 1 kg, the energy required will be $=336\times 1000=3.36\times {10}^{5}J/kg$
Specific heat $=3.36\times {10}^{5}J/kg$