Question

À piece of ice of mass 60 g is dropped into 140 g of water at 50°C.
Calculate the final temperature of water when all the ice has melted.
(Assume no heat is lost to the surrounding)
Specific heat capacity of water = 4.2 Jgk
Specific latent heat of fusion of ice = 336 Jg-1​

Answer 1

The final temperature of water when all the ice has melted is 11 degree Celsius.

Explanation:

Thermal energy gained by ice

The formula to calculate the thermal energy gained by ice is: mass of ice x (L + Cp*T) where L is latest heat of fusion of ice and Cp is specific heat of water.

Therefore, thermal energy gained by ice = 60 x (336 + 4.2*T)

Now calculate thermal energy lost by water

Thermal energy lost by water  = mass of water × Cp × ( 50 - T ) = 140 × 4.2 × (50 - T)

By principle of conservation of energy ---> 60 x (336 + 4.2*T) = 140 × 4.2 × (50 - T)  

Solving the equation yields T = 11 degree Celsius.