# Temperature & Heat

1. Jul 6, 2008

### Kris1120

1. The problem statement, all variables and given/known data

A thermos contains 155 cm3 at 87 degrees C. To cool the coffee, you drop two 12.2-g ice cubes into the thermos. The ice cubes are initially at 0 degrees C and melt completely. What is the final temperature of the coffee in degrees Celsius? Treat the coffee as if it were water

2. Relevant equations

(m*Lf)ice= (c*m*Delta T)water

3. The attempt at a solution

(.0244)(33.5x10^4)= (4186)(155)(Tf-87.0)

T f= 86.987 degrees C

Last edited: Jul 6, 2008
2. Jul 6, 2008

### Hootenanny

Staff Emeritus
What happens to the water that results from the ice melting?

3. Jul 6, 2008

### Kris1120

When the ice melts, it cools the coffee so the overall temperature decreases.

4. Jul 6, 2008

### Hootenanny

Staff Emeritus
Correct. Does the temperature of the melted ice stay at 0oC or does it change?

5. Jul 6, 2008

### Kris1120

The ice gains heat and the coffee loses heat

6. Jul 7, 2008

### Hootenanny

Staff Emeritus
Correct, but you haven't taken this into account in your calculations have you? You need to take into account the temperature change of the ice-water after it has melted.

7. Jul 28, 2008

### Softer1

i think after ice melt , temperature of water (for Ice melt) will up and water in thermos will drop

SO

(m*Lf)ice + (m*c*(Tf-0))ice = (c*m*Delta T)water

(.0244)(33.5x10^4)+(.0244)(4186)(Tf-0)= (4186)(155)(87-Tf)