Science

posted by .

Why does the temperature remain constant around 0 degrees C and 100 degrees C?

For what? For water when it is freezing or boiling? Or do you have another question in mind?

Sorry, it's for water when it is freezing or boiling.

Think of it this way.
Start with a cup of water. Let's say the water weighs 250 grams. We must extract heat from the water, say at room temperature, to reduce the temperature below that of the room. Suppose we continue extracting heat and we get the temperature to 0o C.
To make water freeze, we must extract 80 additional calories for each gram of water we freeze. So we do that and 1 g of the liquid water (at zero C) turns to ice (at zero C). What happens to the other 249 g water. It stays at 0o C. We extract another 80 calories and we freeze another gram of water. Now we have 2 g ice (both pf them at zero C) and 248 g water (at zero C). We extract another 80 calories of heat and we freeze a third gram of ice. Now we have 3g ice (at 0o and 247 g water (at 0o). It doesn't matter what the temperature is that is doing the freezing. It might be in a freezer with a temperature of -20o C but the water will remain at 0o until each molecule of liquid water is frozen. The ice will be at zero C and the liquid water will be at zero C. When the last molecule of water is frozen, then the freezer can start extracting heat from the ice (now all ice and no water) and will eventually lower the temperature to -20o if that is the temperature of the freezer. The same kind of reasoning explains why the temperature of water will not rise above 100o until all of the water is gone. The only difference is that it requires the addition of 540 calories to change a gram of liquid water to steam. The temperature of the water can't rise above 1000 until all of the water has been changed to steam. At that point, we can start heating the steam and the temperature can go above 100. I hope this helps. Its lengthy but thorough, I think.

Thank you, Dr. Bob!

  • Science -

    please tell me the answer in which atmosphere layer a (s) dose the tempereature increase as altitude increse?

Respond to this Question

First Name
School Subject
Your Answer

Similar Questions

  1. some science

    a filter tip or a cigarette acts as both a filter and a condenser. which of the following cannot be removed, assuming the filter tip is 100% efficient?
  2. science

    On the Celsius temperature scale, how many degrees are between the freezing and boiling points of water?
  3. Physics

    I'm trying to determine the specific heat of copper by experiment and I have a question about the change in temperature of the copper. If I take the copper out of boiling water at 100 deg. C and place it in water at 10 degrees C, the …
  4. math

    A new temperature scale has the freezing point of water at 50 degrees and the boiling point of water at 125 degrees. Normal body temperature is 37 degrees C and 98.6 degrees F. Water freezes at 0 degrees C and 32 degrees F and boils …
  5. Physics

    Thank you for any help and assistance. Here is the question/problem: Because of the pressure inside a popcorn kernel, water does not vaporize at 100 degrees Celsius. Instead, it stays liquid until its temperature is about 175 degrees …
  6. Calculus

    The celcius scale is devised so that 0 degrees celcius is the freezing point of water ( at 1 atmosphere of pressure) and 100 degrees celcius is the boiling point of water ( at 1 atmosphere of pressure) . If you are more familiar with …
  7. Chemistry

    Assuming complete dissociation of the solute, how many grams of KNO3 must be added to 275 mL of water to produce a solution that freezes at -14.5 degrees celcius ?
  8. physics

    What are the temperatures for freezing water and boiling water on the Kelvin temperature scale?
  9. Physics

    On planet X, the alien residents use a temperature scale in which they define 0 degrees X to be the melting point of nitrogen and 100 degrees X to be the boiling point of nitrogen. What temperature difference in X degrees does a temperature …
  10. chemistry

    I have the answers, I am just interested in the formulas so that I can solve the problems, thanks! 1. Find the boiling point of a solution composed of 110g of HgCl2 (a non-ionizing solute) in 175g of water. 2. Find the freezing point …

More Similar Questions