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castrodisastro
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Homework Statement
Suppose 337g of water at 32.9°C is poured over a 59.3g cube of ice with a temperature of -5.67°C. Does all the ice melt? If all the ice melts, what is the final temperature of the water? If all of the ice does not melt, how much ice remains when the ice-water mixture reaches equilibrium?
Specific Heat of water = 4.19*103J/(kg*K)
Specific Heat of ice = 2.06*103J/(kg*K)
Latent Heat of fusion of ice = 334*103J/kg
Homework Equations
Q=mCΔT
The Attempt at a Solution
To determine if the process results in either ice, or ice-water mixture, I need to calculate how much heat is required to turn all the ice into water, then calculate how much heat was actually given off by pouring the water onto the ice.
So first
Heat required to raise the temperature of ice, and melt it completely
Q1=miceCiceΔT+miceLheat of fusion
Q1=(0.0593kg)(2.06*103J/(kg*K))(5.67°C)+(0.0593kg)(334*103)J/kg)
Q1=20498.84J
20498.84 Joules required to raise the temp of the ice and melt it completely.
Now how much heat is given off when decreasing the temperature of the water to 0°C
Q2=mwaterCwaterΔT
Q2=(0.337kg)(4.19*103J/(kg*K))(32.9°C)
Q2=46455.79J
More heat is required to freeze the water than to melt the ice, so all the ice will melt.
Here is where I am stuck. So I need to find the final temperature of the water at equilibrium.
To melt the ice requires 20498.84 Joules so I set it equal to mwaterCwater(Tf-Ti) and solve for Tf.
This would tell me the temperature of the water right after the last bit of ice melted into water.
Rearranging this gives me
[Q1+mwaterCwaterTi]/[mwater]Cwater = Tf
Tf=65.8°C (which is impossible since it can't get hotter than when it started)
I should be able to use Tf as the initial temperature of the next phase (rising temp of total water) heading towards equilibrium.
Am I not accounting for something? Should I not set
Q1=mwaterCwaterΔT
to solve for Tfinal
Even after I do that, all I know is the temperature of the total water after the ice melted but have no way of knowing the final temp at equilibrium. If I want to use Q=mCΔT i have two unknows, Tfinal and Q, since I don't know how much heat is taken in as the mixture goes from colder freshly-melted ice-water + warmer liquid water to equilibrium.
What am I not understanding conceptually?
Thanks in advance.
P.S. Don't be rude please.
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