Question

5. Calculate the heat lost by a 0.848 mole of a cobalt metal that decreases its temperature from 45°C to 22°C. The specific heat of cobalt is 0.092 cal/g °C

Answer 1

Cobalt has a molecular weight of 58. 93 g/mole

So, amount of Cobalt present is = (58.93 x 0.848) g = 49.97 g.

Now we have Q = ms(T₂ - T₁) ......... (1)

where, Q = Amount of heat lost, m = Mass of Cobalt present, s = Specific heat of cobalt, T₂ = Final temperature and T₁ = Initial temperature. Since Cobalt metal loses heat T₂ < T₁ and the sign of Q will be neagtive.

Putting the values of all terms in equation (1) we get,

Q = {49.97 x 0.092 x (22 - 45)} cal = - 105.74 cal.

Therefore the amount of heat lost by the Cobalt metal is 105.74 cal.