Question

A solid initially at 0°C is heated. The graph shows the variation in temperature with the amount of heat energy supplied. If the specific heat capacity of the solid is 0.6 Jg⁻¹°C⁻¹, from the graph calculate the (a) mass of solid (b) sp. latent heat of fusion of solid.

Answer 1

(a) The part AB of the graph shows the solid state when the temperature rises from 0 to 90°.

Heat absorbed by the solid (H) = mcθ_R

⇒ 1000 J = m × 0.6 Jg⁻¹°C⁻¹ × 90°С

\[\therefore m=\frac{1000}{0.6 \times 90} \mathrm{~g}\]

= 18.5 g

(b) The part of BC of the graph shows the change of state of solid into liquid.

∴ Heat absorbed (H) = mL

⇒ (3000 – 1000) J = 18.5 g × L

\[\therefore L = \frac{2000}{18.5} \mathrm{Jg}^{-1}\]

= 108.1 Jg⁻¹