# Phase diagram

Question: A solid substance has a vapor pressure of 800 mm Hg at its melting point (80 degrees C). Describe how the solid behaves as temperature is raised from room temperature to 80 C while the atmospheric pressure is held constant at 760 mm Hg.

I think that the the substance will begin to melt a the temp goes up and by the time it hits 80, it will be in the liquid phase because the vapor pressure is below 800 mm Hg.

Is this correct?

Thanks from Sheryl

Vaporization is when a substane turns from a liquid to a gas. Thus, I believe that since the unknown substance's vaporization point is 80 degrees Celsius it will turn into a gas at this point because the temperature is being raised, forcing the intermolecular particles to spread even further apart and to have more entropy (randomness), then a liquid. The particles will also move more rapidly.

Since the vapor pressure of 800 mm Hg is never attained - it stays at 760 - wouldn't it not become a gas?

Sheryl

You are right, but if the vapor pressure was higher it would be a gas. =)

Does the solid go from solid to liquid to gas?

Sheryl

We don't know because we haven't been given the complete phase diagram. It could, or it could go directly to a gas.

Sheryl: The vapor pressure of the solid is dependent on temperature. Somewhere just before it melts at 80 deg, the vapor pressure of the solid is equal to atmospheric pressure, and it vaporizes in an instant (like a solid boiling) to a gas. It never melts, as it does not get to the mp.

Thank you for that clarification. I couldn't get that it doesn't go liquid before vaporizing, now I do.

Sheryl

1. 👍 0
2. 👎 0
3. 👁 955

## Similar Questions

1. ### Phase

http://en.wikipedia.org/wiki/Melting_point Question: A solid substance has a vapor pressure of 100 mmHg at the melting point (100C). Assuming an atmospheric pressure of 760 mmHg, describe the behavior of this solid as the

asked by Lance on November 13, 2006
2. ### Chemistry

What can be said about a substance with a triple point above 1atm 1) The liquid state of the substance cannot exist. 2) The gaseous state at 1 atm pressure cannot be condensed to the solid at the triple point temperature. 3) The

asked by Trinh on August 28, 2015
3. ### Chemistry

The vapor pressure of an unknown substance is given at various temperatures. properties of the substance are: density of solid=1.375g/ml density of liquid= 1.150g/ml. freezing point= 275.0K boiling point=375.0 K How would i

4. ### Chemistry

The vapor pressure of an unknown substance is given at various temperatures. properties of the substance are: density of solid=1.375g/ml density of liquid= 1.150g/ml. freezing point= 275.0K boiling point=375.0 K How would i

5. ### Subliming a substance

Question: A substance has a vapor pressure of 50 mmHg at the melting point (100C). Describe how you would experimentally sublime that substance. My answer: I would put the substance in a sidearm test tube apparatus, put ice in the

asked by Sheryl on November 13, 2006
6. ### Physical Science

1. which of the following should be classified as a suspension? A. soda** B. sand in water C. glass D. milk 2. Which of the following is an of example of a chemical property? A. density B. flammability C. hardness** D. melting

asked by Becky on October 20, 2016
7. ### Sublimes?

Question: An unknown compound gave a melting point of 230C. When the molten liquid solidified, the melting point was redetermined and found to be 131C. Give a possible explanation for this discrepancy. My answer: The compound

asked by Sheryl on October 1, 2006
8. ### Chemistry

Sample A: Solid appearance:crystals, solids, white Solid Conductivity:no Solubility: soluble Solution appearance:substance disappears slowly Solution Conductivity: yes Relative melting point:2nd Sample B: Solid appearance:brown,

asked by Sarah on November 16, 2016
9. ### CHECK my answers Physical science

1. which of the following should be classified as a suspension? A. soda** B. sand in water C. glass D. milk 2. Which of the following is an of example of a chemical property? A. density B. flammability C. hardness** D. melting

asked by anon on May 7, 2017
10. ### Chemistry

How does melting order relate to melting point? A. The substance that melted the quickest has the highest melting point. B. The substance that took the longest to melt has the highest melting point. C. The substance that melted

asked by Noise on November 21, 2019

More Similar Questions