Some very hot rocks have a temperature of 960 ^o C960oC and a specific heat of 150 J/(Kg*K)150JKgK. The rocks are bathed in 12 L12L of boiling water. If the heat of the rocks completely vaporizes the water, what is the minimum combined mass of the rocks?

1 Answer
Feb 5, 2017

210 kg

Explanation:

the heat to vaporize the water:
Q= m_w Q_(v) = 12 kg 2260 (kJ)/(kg) = 27120kJQ=mwQv=12kg2260kJkg=27120kJ
is given from the heat of the rocks that are cooling:
Q= m_rcp_r (Ti-Tf)Q=mrcpr(TiTf)
m_r =Q/(cp_r (Ti-Tf))= (27120kJ)/((0,150(kJ)/(kg°C))(960-100)°C))=210 kg