# Physics - ice to liquid

posted by .

Fifty grams of hot water at 80oC is poured into a cavity in a very large block of ice at 0oC. The final temperature of the water in the cavity is then 0oC. Show that the mass of ice that melts is 50 g.

To melt ice to 50g of water, I think that it will take:
50g(334J/g) = 167,000J

When cooling, the hot water should release:

Specific heat capacity of water(ΔT)(grams of water)(conversion to J from calories) = J released by cooling

(.5cal/g*oC)(80oC)(50g)(4.18J/cal) = 8360J

This is only about half of the energy that is needed to convert the ice to water, so I am missing something. Any ideas?

• Physics - ice to liquid -

I don't know why you converted J to calories. All of that seems unnecessary.
How much heat do you have in the 80 C water if it moves from 80 C to zero (which the problem states as the final T). Therefore,
q = mass water x specific heat water x delta T.
q = 50 x 4.18 x 80 = 16,720 Joules.
How much ice can you melt with that?
16,720/334 = ??
This is almost the same problem we worked on a couple of days ago with the block of ice.

• Physics - ice to liquid -

If you want to work it with calories, the specific heat of water is 1.0 calorie/gram and the heat of fusion for ice is 80 cal/g, therefore
mass H2O x 1 cal/g x 80 = 4,000 calories.
4000 calories/80 cal/g = 50 g ice.

• Physics - ice to liquid -

I am sorry to be a bother - I knew it was like the other problem but I couldn't figure out how. I am taking my class online and am struggling to learn the concepts, basically on my own. While I do well in math, this class has been very difficult for me to get my mind around - it's like learning a new language - with very little help. I now understand what you wrote - my one equation, 50g(334J/g) = 16,700J helped me to see how much energy I needed, I just didn't realize that the book was asking me to go back a chapter to get the equation I used last week. Now I know how to find where that energy comes from, and it even makes sense. Thanks for your patience and help. :-)

## Similar Questions

1. ### physics

0.155 kg of water at 86.0oC is poured into an insulated cup containing 0.224 kg of ice initially at 0oC. How many kg of liquid will there be when the system reaches thermal equilibrium?
2. ### physics

Suppose that 90 g of hot water at a temperature of 75 degrees C is poured into a cavity in a very large block of ice at 0 degrees C. (a) What will be the final temperature of the water in the cavity?

Suppose that 90 g of hot water at a temperature of 75 degrees C is poured into a cavity in a very large block of ice at 0 degrees C. (a) What will be the final temperature of the water in the cavity?
4. ### Physcial Science

Hey There, I have 4 questions that I am totally stumped on... Can anyone help?
5. ### Physcial Science

Hey There, I have 4 questions that I am totally stumped on... Can anyone help?
6. ### Physcial Science

Hey There, I have 4 questions that I am totally stumped on... Can anyone help?
7. ### physical science

You have two cups, one containing 100 g of ice at 0oC, the other containing 100 g of water at 80oC. You pour the hot water into the cup containing the ice. What do you wind up with?
8. ### Science

You have two cups, one containing 100 g of ice at 0oC, the other containing 100 g of water at 80oC. You pour the hot water into the cup containing the ice. What do you wind up with?
9. ### physics

Consider 60 g of hot water at 70 degree C poured into a cavity in a very large block of ice at 0 degree C. A)What will be the final temperature of the water in the cavity?
10. ### physics

A 150g iron ball is dropped into a cavity in a block of ice. The cavity is then found to contain 21g of water. Calculate the heat of fusion of ice.

More Similar Questions