A piece of ice (heat capacity = 2100 J kg − 1 ∘ C − 1 and latent heat = 3.36 × 1 0 5 J kg − 1 ) of mass m gram is at − 5 ∘ C at atmospheric pressure. It is given 420 J of heat so that the ice starts m

Question

A piece of ice (heat capacity = 2100 J kg − 1 ∘ C − 1 and latent heat = 3.36 × 1 0 5 J kg − 1 ) of mass m gram is at − 5 ∘ C at atmospheric pressure. It is given 420 J of heat so that the ice starts melting. Finally when the ice-water mixture is in equilibrium, it is found that 1 g of ice has melted. Assuming there is no other heat exchange in the process, the value of m is

TestHub · Accepted Answer

Language of question is slightly wrong. As heat capacity and specific heat are two different physical quantities. Unit J − kg − 1 ⋅ ∘ C − 1 . The heat capacity given in the question is really the specific heat. Now applying the heat exchange equation. 420 = ( m × 1 0 − 3 ) ( 2100 ) ( 5 ) + ( 1 × 1 0 − 3 ) ( 3.36 × 1 0 5 ) ​ Solving this equation we get, m = 8 g ∴ The correct answer is 8 .

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