Solving Specific Heat Problem: Copper Calorimeter

[9giddjl]

Specific Heat-- please help!

Homework Statement

A piece of copper of mass 0.5 kg is heated to 610 degrees celcius and then dropped into a copper calorimeter of mass 0.11 kg containing 0.13 kg of water at 21 degrees celcius. If the specific heat of copper is 390 J/Kg/K, calculate the mass of water lost by boiling.

Homework Equations

mC(Tf-Ti)= mC(Tf-Ti) + mc(Tf-Ti) + mLv

The Attempt at a Solution

Qlost(copper)= Qgained (copper and water)
mC(tf-Ti) = mC(tf-ti) + mc(Tf-Ti) + mLv
0.5 x 390 x (610 -21) = 0.11 x 390 x (100-21) + 0.13 x 4200 x(100-21) + m2.25 x 10^6

I thought that, because the water is boiled and thus water is being lost (steam) then the final temp of the water and copper calorimeter is 100 degrees celcius.. am i on the right track? pls help me

 

[anathema]

Thank you for bringing up this question about specific heat. It seems like you are on the right track with your solution, but there are a few things that can be clarified.

Firstly, your equation is correct, but you have not taken into account the mass of the water lost by boiling. This should be included in the calculation as a negative term, since it is leaving the system.

Secondly, you are correct in thinking that the final temperature of the water and calorimeter is 100 degrees Celsius, since this is the boiling point of water. However, you will need to use this temperature in your calculations to determine the amount of water lost by boiling.

Lastly, you will need to use the specific heat of water (4200 J/kg/K) in your calculation, since the water is being heated from 21 degrees Celsius to 100 degrees Celsius.

I hope this helps clarify your solution. Let me know if you have any further questions. Good luck with your calculations!

 

[thomate1]

You are on the right track, but there are a few things that need to be clarified. First, the final temperature for the water and calorimeter should be the boiling point of water, which is 100 degrees Celsius, as you mentioned. However, for the copper, the final temperature should be the same as the water and calorimeter, since they will all be in thermal equilibrium after the experiment. So the final temperature for copper should also be 100 degrees Celsius.

Secondly, when calculating the energy gained by the water and calorimeter, you need to take into account the specific heat of water and the specific heat of the calorimeter. The equation should be:

Qgained (water and calorimeter) = mc(Tf-Ti) + mc(Tf-Ti)

Where m is the mass of water and calorimeter, and c is the specific heat of water and the calorimeter. You can find the specific heat of the calorimeter by looking it up or assuming it is the same as copper.

Finally, to calculate the mass of water lost by boiling, you need to rearrange the equation to solve for m (mass of water lost):

m = (mC(tf-Ti) - mc(Tf-Ti) - mLv) / Lv

Substitute in the values from the problem and solve for m. This will give you the mass of water lost by boiling. I hope this helps!