Some very hot rocks have a temperature of $600 ^o C$ and a specific heat of $250 J/(Kg*K)$ . The rocks are bathed in $50 L$ of boiling water. If the heat of the rocks completely vaporizes the water, what is the minimum combined mass of the rocks?

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Answer 1 · 2017-08-24T17:03:10

The mass of the rocks is $=902.8kg$

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

For the rocks $DeltaT_o=600-100=500^@C$

Heat of vaporisation of water

$H_w=2257kJkg^-1$

The specific heat of the rocks is

$C_o=0,25kJkg^-1K^-1$

The mass of water is $m_w=50kg$

$m_o C_o (DeltaT_o) = m_w H_w$

$m_o*0.25*500=50*2257$

The mass of the rocks is

$m_o=(50*2257)/(0,25*500)$

$=902.8kg$

Some very hot rocks have a temperature of 600 ^o C600 ^o C and a specific heat of 250 J/(Kg*K)250 J/(Kg*K). The rocks are bathed in 50 L50 L of boiling water. If the heat of the rocks completely vaporizes the water, what is the minimum combined mass of the rocks?