Melting Ice in water and the final Temperature

In summary, it is possible for water to have a temperature below 0oC if a solute, such as salt, is dissolved in it, which is known as freezing point depression. In the absence of a solute, the temperature of ice and water should be at 0oC while the ice is melting. However, in some cases, the temperature of pure water can decrease to around -5oC before any ice forms. The accuracy of the temperature readings also depends on the source and composition of the water, as well as the measurement method.
  • #1
wakejosh
102
0
I have heard that when ice mixes completely with water then the Ice will be completely melted and the temperature of the water willl actually be below 0 C, is this true?
 
Physics news on Phys.org
  • #2
wakejosh said:
I have heard that when ice mixes completely with water then the Ice will be completely melted and the temperature of the water willl actually be below 0 C, is this true?
Yes, it is possible to have water at a temperature less than 0oC if it has some solute (e.g. salt) dissolved in it, this is known as freezing point depression. In general, the more solute(salt) you add to a solvent(water), the lower the freezing (and hence boiling) point becomes.
 
  • #3
But also in the absence of a solute, Icewater should be at 0C while the ice is melting, I believe, since it is at the phase transition temperature. Is that right Hootenanny?
 
  • #4
well, he didnt say anything about ice, one of my freinds says he doesn't think the TA is right, and I don't know how much I trust him either. His observation was in regards to this question:

a 32 oz cup with 8 ounces of ice (250g about .25 liter volume) at zero degrees C is added to 750 g of water at 25 C.

he says that when they have mixed the Ice will be melted and the water can actually be below 0 C, he said nothing about Salt, nor does the problem.

From what you have said it sounds like when they are mixed the Ice will not be compltely melted and the temperature will be about 0 C. you guys think this is more accurate? I do.
 
  • #5
berkeman said:
But also in the absence of a solute, Icewater should be at 0C while the ice is melting, I believe, since it is at the phase transition temperature. Is that right Hootenanny?
This is indeed true, thermal energy is transferred from the water (and other surroundings) to increase the internal energy of the ice. As an aside, I have seen examples where the temperature of pure water (distilled) has been reduced to around -5oC before any ice has formed, however, once ice is formed the temperature increases again back up to 0oC.
 
  • #6
wakejosh said:
he says that when they have mixed the Ice will be melted and the water can actually be below 0 C, he said nothing about Salt, nor does the problem.
Is the water from a tap or distilled? What are you measuring the temperature with?
 
  • #7
Hootenanny said:
Is the water from a tap or distilled? What are you measuring the temperature with?

none of that was specified in the question.
 

1. How does melting ice affect the temperature of water?

When ice melts in water, it absorbs heat from the surrounding liquid and cools it down. This is because melting requires energy, known as latent heat, to break the bonds between water molecules. As a result, the final temperature of the water will be lower than the initial temperature.

2. Does the amount of ice affect the final temperature of water?

Yes, the amount of ice present in the water will impact the final temperature. The more ice that is added to the water, the more heat will be absorbed during the melting process, resulting in a greater decrease in the final temperature of the water.

3. What factors can affect the final temperature of water when ice is added?

Aside from the amount of ice, other factors that can affect the final temperature of water when ice is added include the initial temperature of the water, the type of container the water is in, and the rate at which the ice is melting. These factors can influence the rate of heat transfer between the ice and the water.

4. Can the final temperature of water ever be lower than 0 degrees Celsius when ice is added?

No, the final temperature of water will never be lower than 0 degrees Celsius when ice is added. This is because the temperature of ice is 0 degrees Celsius and it will continue to absorb heat until it reaches this temperature, at which point it will begin to melt.

5. How does salt affect the melting of ice in water?

Salt lowers the freezing point of water, which means that it requires a lower temperature for water to turn into ice. When salt is added to ice and water, it disrupts the balance between the freezing and melting points, causing the ice to melt at a faster rate. This results in a lower final temperature for the water compared to if no salt was added.

Similar threads

  • Introductory Physics Homework Help
Replies
3
Views
947
  • Introductory Physics Homework Help
Replies
11
Views
970
  • Introductory Physics Homework Help
Replies
1
Views
973
  • Introductory Physics Homework Help
Replies
4
Views
1K
  • Introductory Physics Homework Help
Replies
17
Views
3K
  • Introductory Physics Homework Help
Replies
8
Views
2K
  • Introductory Physics Homework Help
Replies
12
Views
1K
  • Introductory Physics Homework Help
Replies
1
Views
947
  • Introductory Physics Homework Help
Replies
1
Views
1K
  • Introductory Physics Homework Help
Replies
2
Views
820
Back
Top