[cyuan92]

An 80-pound ice sculpture is the centerpiece of a table under a tent during an outdoor party.  It was kept in a 0 Celsius degree freezer until 12:00 noon when the party began.  The tent temperature was 80 degrees Fahrenheit.
 
Specific heat of water = 4.184 J / g K
Hvap(H2O) = 2260 J / g
Hfus(H2O) = 333 J / g
1 kcal = 4184 J
 
A. How much energy is necessary to completely melt the sculpture?
 
B. How much energy is required for the melted ice to evaporate?
 
C. After reaching 70 degrees Fahrenheit, how much energy must be removed to refreeze the melted ice?
 
D. At 3:00 p.m., how much of the ice sculpture has melted if 80 degrees Fahrenheit was equivalent to 126.5 W?

I know I have to convert the temperature to Celsius and convert the pounds to grams. I used the equation Q=Cp x M x Change in temp. This is a practice question for a chemistry competition next week. Any help is appreciated. Thanks!

q= Cp x m x change in temp
12,094,560 = 4.184 x 36320g x n
n= 79.5889 degrees

This is all I can do >.<

[boostar]

Surely you could put a little working up?

[0000000]

I know I have to convert the temperature to Celsius and convert the pounds to grams. I used the equation Q=Cp x M x Change in temp. This is a practice question for a chemistry competition next week. Any help is appreciated. Thanks!

We will help you, but firstly you have to try to solve it.
Write back with your answers and we will correct you in case of mistakes.

One thing, you don't need to convert the temperature to Celsius but to Kelvins, and first check the equations needed.

by the way, this is a Physical Chemistry problem:)

[cyuan92]

Okay, I added some work.

[enahs]

Take this step-wise.

A)

How much energy is required to melt that amount of ice?

You have your Enthalpy of Fusion. 333J/g. How many grams do you have, and thus how many joules do you need? This is just multiplying one by the other. Look at the units, cancel the units.

B)
You now have that many grams of water, this is the same as part A only using the Enthalpy of Evaporation.

C)
How much energy is required to cool the water from 70 degrees F (converted to C) to zero degrees C? How much energy is require to then freeze that mass of ice?