Question

5. An unknown metal has a mass of 4.67g. It is heated to 95.1°C and then placed in a calorimeter that contains 24.3g of water at 21.7°C. The metal and water both reach a final temperature of 24.6°C. What is the specific heat of this metal? What is the unknown metal?

Answer 1

Let's assume that the specific heat of the metal is C cal g^-1 K^-1.

It is given that the temperature of 4.67 g of metal at 95.1 ⁰C cools to 24.6 ⁰C on adding to the calorimeter.

Heat released by the metal = Mass * Specific heat * Temperature change = 4.67 * C * (95.1 - 24.6)

= 329.235 * C cal

It is given that 24.3 g of water at 21.7 ⁰C gets heated to 24.6 ⁰C due to metal.

Heat absorbed by water = mass * Specific Heat * Temperature change

= 24.3 * 1 * (24.6 - 21.7) = 70.47 cal (Specific heat of water = 1 cal g^-1 K^-1)

By conserving energy, Heat released by metal = Heat absorbed by water

329.235 * C = 70.47

Solving, we get C = 0.214 cal g^-1 K^-1

This corresponds to the metal Aluminium.