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erok81
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Homework Statement
Your 200-g cup of tea is boiling-hot. About how much ice should your add to
bring it down to a comfortable sipping temperature of65°C . Assume that the ice is
initially at−15°C . The specific heat capacity of ice is 0.5cal g⋅°C , for water is 1 cal g⋅°C.
The latent heat for melting ice is 80cal g.
Homework Equations
Equation for latent heat: L=Q/m
The Attempt at a Solution
First I need to find the heat lost by the water. This is done using:
Q=cwmwΔT → (1 cal g⋅°C)(200 g)(65 C - 100 C)
Q=-7000 calories
Assuming no heat is lost to anything else during the process, Qlost = Qgained
So the ice cube gains the heat lost by the water, or 7000 calories.
Here is where I am stuck.
I tried using the latent heat equation directly (L=Q/m → m=Q/L) using the latent heat of melting ice a 80 cal/g, but this gave me the incorrect answer.
How does one figure out the mass? I tried subbing in the specific heat capacity for Q in the latent heat eqn, but then my masses cancelled. So that didn't work.