A copper ball and an aluminum ball of mass 150 g each are heated to 100°C and then cooled to a temperature of 20°C. The heat lost by the copper ball is 4.6 kJ. The heat lost by the aluminum ball is 10.8 kJ. What is the specific heat of copper, if the specific heat of aluminum is 0.90 J/g°C?

Respuesta :

The specific heat of copper is 0.38 J/g° C.

Explanation:

We can directly compute for the specific heat of copper using the formula:

                                    ΔH = m C ΔT

where ΔH represents the change in enthalpy or heat lost,

             m represents the  mass,

             C represents the  specific heat and

            ΔT represents the  change in temperature

    4,600 J = 150 g * C * (100 °C - 20°C)

              C = 0.38 J/g°C.

Since the initial temperatures and final temperatures of the two balls are the same and the mass of the two balls are equal,

(heat lost by the copper ball/heat lost by the aluminum ball) = (ccopper/ caluminum)

So ccopper = (heat lost by the copper ball/heat lost by the aluminum ball) × caluminum

= (4.6 × 0.9) ÷ 10.8 = 0.38 J/g°C