Some very hot rocks have a temperature of #480 ^o C# and a specific heat of #180 J/(Kg*K)#. The rocks are bathed in #18 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
G_Ozdilek
Aug 24, 2016

879 grams (based on the assumptions provided below)

Explanation:

Specific heat of water (at 100 degrees Celsius) = 4219 J/(kg*K)
18 L of boiling water = 17.244 kg (since at 100 degrees Celsius density of water = 958 g/L).

When you apply latent heat formula (mcDelta T) and suppose water temperature increased only 1 degrees Celsius, and further temperature of rocks dropped to 20 degrees Celsius,

#m*180*460 = 17.244*1*4219#

m shows total mass of the rocks.

#m=0.879 kg#

or #m=879 g#

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