(a)What is the specific latent heat of the metal?
(b) If the specific heat capacity of metal is 200 J kg-1 K-1, how much additional heat energy will the metal give out in cooling to – 50oC?
Solution:
According to the question, mass of metal = 150 g
and the specific latent heat of metal is
L = Q / m = 75000 / 150
Therefore, L = 500 J g-1
and the specific heat capacity of metal is 200 J kg-1 K-1
In this case, the change in temperature = 800 – (-50) = 800 + 50
= 8500 C (or 850 K)
We know that the expression for heat energy is given by => △Q = mc△T
△Q = 0.15 × 200 × 850 = 25500 J