# PHysics-almost complete!

posted by .

In a physics lab experiment, a student immersed 205 one-cent coins (each having a mass of 3.00 g *.003kg) in boiling water. After they reached thermal equilibrium, she quickly fished them out and dropped them into 0.244 kg of water at 20.0 C in an insulated container of negligible mass.

What was the final temperature of the coins? [One-cent coins are made of a metal alloy - mostly zinc - with a specific heat capacity of 390 J/(kg*K).]

I know that:
Mass,coins=.615 kg
Mass,water=.244 kg
c,coin=390 J/(kg*K)
c,water=418.6 J/(kg*K)
Ti, coins= 100C, 373.15K
Ti, water= 20C, 293.15K

The problem asks for the Tf of the coins, but I'm still missing the Tf of the water...I'm thinking it has something to do with the equilibrium point, but I dont' know that that is!

Heat lost by the coins + heat gained by the water = 0

mass x specific heat x (Tf - Ti) + mass x specific heat x (Tf - Ti) = 0

• PHysics-almost complete! -

You posted this yesterday and I gave you the formula, which you have copied.
I think you have missed the point. For the first
mass x specific heat x (Tf-Ti) , you have mass coins, spcific heat of coins, and Ti of coins.
For the second mass x specific heat x (Tf-Ti) you have
mass water, specific heat water, and Ti of water. That leaves only one unknown, namely, Tfinal which is what you are looking for. Solve the above for Tf. BIG Hint: Won't the Tf of the water be the same as the Tf of the coins. You're putting hot coins in cool water and both will come to some final T. The coins will lose heat, the water will gain heat, and the process of losing and gaining will stop WHEN BOTH ARE THE SAME. That will be Tfinal. Solve for Tfinal.
Post your work if you get stuck.

• PHysics-almost complete! -

ok, i thought i had an answer, but it wasn't correct...here was my work...

(.615)(390)(T-373.15)=(.244)(418.6)(T-293.15)=0
T=349.2571663 -> C=76.1071663

When I used that T in the equation it worked... =(

• PHysics-almost complete! -

It's set up right. All you need to do is to solve for T. You can make the numbers a little smaller if you use C instead of K. It's the difference you want and the difference is the same in K or C.

## Similar Questions

1. ### PHYSICS

In a physics lab experiment, a student immersed 205 one-cent coins (each having a mass of 3.00 g *.003kg) in boiling water. After they reached thermal equilibrium, she quickly fished them out and dropped them into 0.244 kg of water …

In a physics lab experiment, a student immersed 205 one-cent coins (each having a mass of 3.00 g *.003kg) in boiling water. After they reached thermal equilibrium, she quickly fished them out and dropped them into 0.244 kg of water …
3. ### Physics, almost have it!

In a physics lab experiment, a student immersed 205 one-cent coins (each having a mass of 3.00 g *.003kg) in boiling water. After they reached thermal equilibrium, she quickly fished them out and dropped them into 0.244 kg of water …
4. ### Physics

In a physics experiment, Wendy immersed a copper of mass 300g in 100 degree C in boiling water and left it there for several minutes. She then transferred the cube to 0.2 kg of water at 10 degrees C. The final temperature of the mixture …
5. ### Chemistry

A sample of zinc with a mass of 14g was heated to 98 degree celsius in boiling water and then dropped into a beaker containing 4.5x10^4ng of water at 25 degree celsius. when the water and metal came to thermal equilibrium, the temperature …
6. ### Chemistry

A 237 g piece of molybdenum, initially at 100.0°C, is dropped into 244 g of water at 10.0°C. When the system comes to thermal equilibrium, the temperature is 15.3°C. What is the specific heat capacity of molybdenum?
7. ### Physics

A 500 g glass beaker is in thermal equilibrium with 100 ml of 20 Degrees celsius water in it. If a 5 g sample of copper is placed into the water and the system is allowed to come into thermal equilibrium, what will the final temperature …
8. ### math

Sasa had some 20-cent and 50-cent coins. 7/8 of the coins were 20-cent coins and the rest were 50-cent coins.After Sasa had spent \$72.50 worth of 50-cent coins and 5/7 of the 20-cent coins, she had 2/7 of the coins left. Find the total …
9. ### Chemistry

a 191 g piece of copper is heated to 100 C in a boiling water bath and then dropped into a beaker containing 755 g of water (density =1.00 g/cm3) at 4.0 C. What is the final temperature of the copper and water after thermal equilibrium …
10. ### Physics

A 3.40 kg block of copper at a temperature of 74 °C is dropped into a bucket containing a mixture of ice and water whose total mass is 1.20 kg. When thermal equilibrium is reached the temperature of the water is 14 °C. How much ice …

More Similar Questions