Some very hot rocks have a temperature of 450 ^o C and a specific heat of 70 J/(Kg*K). The rocks are bathed in 70 L of boiling water. If the heat of the rocks completely vaporizes the water, what is the minimum combined mass of the rocks?

1 Answer
Mar 23, 2017

The mass of the rocks is =6448.6kg

Explanation:

The heat transferred from the rocks to the water, is equal to the heat used to evaporate the water.

For the rocks DeltaT_o=350º

m_o C_o (DeltaT_o) = m_w H_w

Heat of vaporisation of water

H_w=2257kJkg^-1

C_o=0.07kJkg^-1K^-1

m_0 C_o*350 = m_w* 2257

m_o*0.07*350=70*2257

m_o=(70*2257)/(0.07*350)

=6448.6kg