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Phase Diagrams show what effect temperature and pressure have on a pure substance in a closed system without any air.

The Phase Diagram

Concept #1: The Properties of the 3 Phases of Matter 

Transcript

Welcome back, guys. In this new video, we’re going to take a look at Phase Diagrams. Now,
We’ve talked about this way back in the beginning of the semester. We’re going to say under appropriate conditions of pressure and temperature, matter exists in three different forms. Matter can exist as a gas, a liquid or a solid.
Now, when it comes to each of these different states or phases of matter, they have different properties that are specific to them. So if we take a look here, we're going to have a microscopic explanation for the behaviour of all three phases.
We’re going to say gases, they assume the shape and volume of their container. If you have a large container, you input gas in there; the gases will spread out as far as possible to take up as much space as they can inside the container. We say that this is the gas behaving ideally.
Liquids assume the shape of the portion of its container it occupies, but not the volume, not always. Because let’s say we have a container that can hold a gallon of water and the gallon is shaped a specific way, but let’s say we don’t have a gallon of water. Let’s say we have only half a gallon of water and we pour it into the container. The water will take up half of the volume and take up the shape but it won’t be able to take up the rest of the volume because there’s not enough water. So water, liquids, always take up the shape but not necessarily the volume. If there’s not enough liquid, it won’t be able to fill up the entire container.
Solids are very stubborn. Solids maintain a fixed volume and shape. So you have a container, you dump a rock in there. The rock does not conform. It doesn’t change its shape to fit the container. It doesn’t try to fill up the container. It is what it is.
Now, compressibility, we’ve talked about this as well. Compressibility has to do with us being able to push down on the molecules that make up that phase.
Gases are highly spread out inside a container, but if I apply pressure, I can compress them, squeeze down so that those gas particles, gas molecules, get closer and closer together. So we’re going to say gases are highly compressible. I can increase the pressure and squeeze their molecules closer.
Now, liquids are not far apart. They’re right on top of each other but they’re fluid. They can move around each other. There’s not much space, not much free space between them. They’re rubbing up against each other. So we’re going to say that liquids are not really compressible. We might be able to squeeze a little bit but overall they’re not compressible because the molecules are already as close as they’re going to be. They’re just rubbing up against each other as they’re sliding around and moving around.
Solids, their molecules are frozen in place. They’re already as close as they’re going to be. They’re stacked on top of each other. So we’re going to say that solids are not compressible, not at all.
Then we’re going to say viscosity. Viscosity is just the resistance to flow. That means it doesn’t want to move. So we talked about this earlier too. If you make a comparison between a bucket of water and bucket of honey. So if you take the bucket of water and turn it upside down on someone’s head, the water is going to come right down and drench that person. But let’s say we have a bucket of honey. Honey moves a lot slower than water. Honey is more viscous, it doesn’t want to move as fast. So if I take that bucket and dump it over someone’s head, some of it might come out immediately but a good majority of it is going to take time to come out.
How do we decrease viscosity? If you increase the temperature, you’re going to excite the molecules. The molecules get faster, that honey will come flowing out faster. So if you increase temperature, you decrease viscosity.
So we’re going to say gases, gases are bouncing all over the place. They move incredibly fast, so they’re going to have low viscosity. They don’t have a resistance to flow. They want to move as fast as they can. Liquids have moderate viscosity. Depending on the liquid, they can flow fast or slow. And then solids really don’t flow, they’re just what they are. So solids have a high viscosity.
So these are each of the microscopic explanations of each of these phases of matter and remember especially the terms viscosity because these are the terms that you’re going to be associating with intermolecular forces and all the other things that we talked about when drawing a compound.

Concept #2: Understanding the Phase Diagram

Transcript

Associated with the three different phases are these properties but also what we call a phase diagram. We’re going to say this shows the effect that temperature, temperature down here, and pressure have on a pure substance in a closed system. So there’s no air entering the system. We’re going to say any substance, when we do a phase diagram we can look at its three phases. We can have its solid phase, its liquid phase. and its gas phase. And the phase diagram basically explains at such a temperature and such pressure, what phase will that matter exist as. Will it exist as a solid, a liquid or a gas at this particular temperature and this particular pressure? That’s all the phase diagram is really useful for.
And what we’re going to say is this phase diagram represents a compound and the only compound it doesn’t represent is water. Water is a very unique substance. If you think about it, if you freeze water, it becomes ice, right? Let’s say you take that ice cube and you dunk it into a cup of water. What usually happens is the ice cube actually floats on top of the water. This means that the ice, the solid, is actually less dense than the liquid. The solid ice weighs less, that’s why it’s able to float on the surface of the liquid. This is a weird phenomenon that happens only with water.
All other substances, when you freeze them to a solid and you drop them in their liquid form, the solid naturally just sinks to the bottom, which is what we expect, but water isn’t that way. And, again, why does water behave this way? Because of the H bonding that exists in water. The H bonding that exists between the molecules give them a certain orientation and when you freeze them, this orientation gets changed even further giving us a special shape. This special shape allows the solid to float on its liquid form.
So the phase diagram for water is different in this way. You see this line here? This line points towards the right. That signifies that this phase diagram is any compound except water. Water’s line points to the left. It’s the only one where that line is going to move towards the left. We’re going to say here, as the temperature and pressure increase, we’re going to say that the liquid portion becomes more dense. That’s what moving that line over to the left really signifies.
And we’re going to say how do we read this phase diagram? Well, we’re going to say a phase diagram again shows all three states. We’re going to say here, if we’re going straight from solid to gas, that phase change is called sublimation and that can happen. Carbon dioxide can go straight from a solid to a gas skipping the liquid phase altogether.
If we’re going from a gas to a solid, we’re depositing a solid so that’s deposition. If we’re going from a solid to a liquid, then we’re going to say that that is melting or what we call fusion. So remember fusion or melting mean the same thing. If we’re going from a liquid to solid, that’s freezing. If we’re going from liquid to gas, that’s vaporization. If we’re going from gas to liquid, that’s condensation. We should know all of these different types of phase changes.
Next, we’re going to say that let’s say that this is point A, point B, point C and point D. We’re going to say at point B, we have something called the triple point. At the triple point, the substance exists in all three phases. At that point, exists as a liquid, a solid and a gas, all at once, the triple point.
We’re going to say at point D, point D is called the critical point. The critical point is the last point on our phase diagram where our substance can exist as a liquid or a gas. If we go beyond the critical point, the substance becomes something entirely different. It becomes a substance that we can’t recognize. It becomes a substance called liquid plasma. The temperature is so high, the pressure is so high that the compound doesn’t look like a solid or a gas anymore. We can’t recognize it. It looks like liquid plasma. If you wanted to realize what does liquid plasma looks like just think of lava or maybe the sun. If you could like physically reach the sun and grab a chunk of it, that’s what liquid plasma would look like or lava will probably be the closest thing on earth that we can say liquid plasma looks like.
So again, the critical point is the last point at which we can still recognize the substance. Once we go a little bit beyond the critical point, we can’t tell if it’s a liquid or a gas anymore and it looks like something called liquid plasma.
And then we’re going to say that these other major portions of the phase diagram. So one, remember, that water has a different phase diagram from all other substances, and then to recognize the different points associated with the phase diagram. We have three phases of matter and the phase diagram just explains how temperature and pressure play a role on going from one phase to another phase.

The phase diagram looks at the transition of matter between the phases of solid, liquid and gas as temperature and pressure are affected.

Practice:

Answer the following questions based on the image above: 

a. At what temperature can we no longer tell the difference between the liquid and the gas? _____________

 b. Which point represents an equilibrium between the solid, liquid and gas phase?    _____________

 c. Which line segment represents an equilibrium between fusion and freezing? _____________

 d. Which line segment represents an equilibrium between sublimation and deposition? _____________

 e. Which line segment represents an equilibrium between condensation and vaporization? _____________

 f. What is the normal freezing point of this unknown substance? _____________

 g. What is the normal boiling point of this unknown substance? _____________

What does letter D represent?  a. fusion curve b. triple point c. sublimation point d. melting point e. critical point
What is the name of the process of direct conversion of a solid to a gas? a) crystallization b) sublimation c) vaporization d) condensation e) deposition
The graph shows how the vapor pressure of a liquid changes with temperature. Select the choice that best indicates the degree of correctness of this statement: "The normal boiling point of the liquid is 78°C." (A) The statement is true. (B) The statement is probably true; additional data would be needed for a final decision. (C) The statement is probably false; additional data would be needed for a final decision. (D) The statement is false.
Based on the phase diagram shown below, how will the melting point of the substance change if the pressure is increased above 1 atm? A)      The melting point will decrease. B)      The melting point will remain the same. C)      The melting point will increase. D)      The substance will not melt at pressures of 1 atm and above; instead, the solid sublimes to form the gas phase.
Draw and label a phase change diagram.
A pure substance can exist simultaneously as a solid, liquid, and gas only at a) no point b) more information is needed c) any point d) the triple point e) the critical point  
In the phase diagram of a substance shown  to the right, fill in the blanks to make correct statements. a) Moving from point B to C results in a transition from _______ phase to ________ phase. b) At point _______ all three phases of solid, liquid, and gas coexist in equilibrium. c) At a higher pressure and temperature than point ______ the substance becomes a supercritical fluid. d) At point F, ______ phase and ______ phase coexist in equilibrium. 
Consider the phase diagram shown below, starting at 0.4 atm and 20°C what phase change will occur if we decrease the temperature to -100°C?  a) Vaporization b) Condensation c) Sublimation d) Deposition e) Melting  
The phase diagram for a compound is shown below. Describe the phases and transitions as the pressure is increased from 0.5 atm to 1.2 atm at a constant temperature of 75 °C.  
In the phase diagram, which transition represents the condensation of a gas into a liquid? (A) B to A (B) D to B (C) C to D (D) A to D
Which of the following involves a change in temperature during the phase transition?   a. deposition of carbon dioxide b. fusion of ethanol c. condensation of ammonia d. all of the above e. none of the above
A sample is at the temperature and pressure indicated by point (c) on the phase diagram below. What phase is present after the pressure is increased to the critical pressure at constant temperature? A.  Gas B.  Liquid C.  Solid D.  Supercritical fluid E.  More than one phase is present
The phase diagram of CO2 is shown here. It's in Russian but you know enough science to be able to translate the words.
The phase diagram for a substance is depicted to the below; the substance is a solid at room temperature conditions, 1.0 atm and 20°C. You wish to sublimate the solid, what change(s) must you make in order for this to occur? a) Increase the temperature. b) Decrease the pressure. c) Decrease the temperature, then decrease the pressure. d) Decrease the pressure, then increase the temperature. e) Increase the temperature, then increase the pressure.
Give the change in condition to go from a liquid to a gas.   A) increase heat or reduce pressure B) increase heat or increase pressure C) cool or reduce pressure D) cool or increase pressure E) none of the above 
You have a sample of Xe at 164 K and 760 torr. You reduce the pressure to 250 torr. According to Figure 1, what happens? A. It melts. B. It vaporizes. C. It condenses. D. It solidifies. E. Nothing. No phase change occurs.
Consider the phase diagram shown.  Choose the statement below that is TRUE.   A) The triple point of this substance occurs at a temperature of 31°C. B) At 10 atm of pressure, there is no temperature where the liquid phase of this substance would exist. C) The solid phase of this substance is higher in density than the liquid phase. D) The line separating the solid and liquid phases represents the ΔHvap. E) None of the above are true.  
Sulfur can exist as a gas, a liquid, or as one of two solid states: rhombic and monoclinic. A phase diagram for sulfur is shown below: a. What is (are) the thermodynamically-stable phase(s) of sulfur at room temperature and pressure (i.e. 1.0 atm at 25°C)?     b. Which state of sulfur is more dense: rhombic, monoclinic, or liquid?
Consider the phase diagram shown below .Identify the phase present at points a.
Consider the phase diagram shown below .Identify the phase present at points b.
Consider the phase diagram shown below .Identify the phase present at points c.
Consider the phase diagram shown below .Identify the phase present at points d.
Consider the phase diagram shown below .Identify the phase present at points e.
Consider the phase diagram shown below .Identify the phase present at points f.
Consider the phase diagram shown below .Identify the phase present at points g.
The phase diagram for sulfur is shown below. The rhombic and monoclinic phases are two solid phases with different structures .Below what pressure will solid sulfur sublime?
The phase diagram for sulfur is shown below. The rhombic and monoclinic phases are two solid phases with different structures .Which of the two solid phases of sulfur is most dense?
The high-pressure phase diagram of ice is shown at the top of the next column. Notice that, under high pressure, ice can exist in several different solid forms .What is the density of ice II compared to ice I (the familiar form of ice.)
Examine the phase diagram for iodine shown in Figure 11.39 in the textbook.What phase transitions occur as you uniformly increase the pressure on a gaseous sample of iodine from 0.010 atm at 185 oC to 100 atm at 185 oC?
What is the significance of the critical point in a phase diagram?
Based on the phase diagram of CO2 shown in the figure, describe the phase changes that occur when the temperature of CO2 is increased from 190 K to 350 K at a constant pressure of 1 atm.
Why does the line that separates the gas and liquid phases end at the critical point?
What is the significance of the triple point in a phase diagram?
The table below lists the density of O2 at various temperatures and at 1 atm. The normal melting point of O2 is 54 K. Temperature (K) Density (mol/L) 60 40.1 70 38.6 80 37.2 90 35.6 100 0.123 120 0.102 140 0.087 Over what temperature range is O2 a solid?
The table below lists the density of O2 at various temperatures and at 1 atm. The normal melting point of O2 is 54 K. Temperature (K) Density (mol/L) 60 40.1 70 38.6 80 37.2 90 35.6 100 0.123 120 0.102 140 0.087 Over what temperature range is O2 a liquid?
The table below lists the density of O2 at various temperatures and at 1 atm. The normal melting point of O2 is 54 K. Temperature (K) Density (mol/L) 60 40.1 70 38.6 80 37.2 90 35.6 100 0.123 120 0.102 140 0.087 Estimate the normal boiling point of O2.
What is a phase diagram?
Label generic phase diagram’s important features.
What is the significance of crossing a line in a phase diagram?
A substance has a triple point at -24.5 oC and 225 mm Hg. What is most likely to happen to a solid sample of the substance as it is warmed from -35 oC to 0 oC at a pressure of 220 mm Hg?
A flask of water is connected to a vacuum pump. A few moments after the pump is turned on, the water begins to boil. After a few minutes, the water begins to freeze. Explain why these processes occur.
A particular liquid crystalline substance has the phase diagram shown in the figure.By analogy with the phase diagram for a non-liquid crystalline substance (Section 11.6), identify the phase present in each area.
Explain what happens to a substance when it is heated in a closed container to its critical temperature.
Why does increasing the temperature cause a solid substance to change in succession from a solid to a liquid to a gas?
The phase diagram for SO2 is shown here. At which of the three red points does SO2(g) behave least ideally?
Complete this table describing the shape and volume of each phase.                             Shape           Volumefixed            Solid    ____            _____variable       Liquid   ____           _____                    Gas      ____           _____
Which of the following states of matter is classified as a condensed phase?a) solidb) liquidc) gasd) Both a and be) Both a and b and c
Consider this phase diagram for carbon dioxide.a. In what phase is CO2 at 72 atm and 0 degree C? b. Starting from the point described above, what phase change would eventually result from a decrease in pressure?
A gas or vapor may be liquefied only at temperatures(A) equal to the normal boiling point.(B) above the normal boiling point.(C) above the critical temperature.(D) at or below the critical temperature.
The oxides of concern in a coal-burning power plant are sulfur oxides, not nitrogen oxides. The diagram for SO2 is shown below (not drawn to scale). a. What is the lowest temperature at which liquid SO 2 exists? b. Which is more dense: solid SO2 or liquid SO2? c. What is the normal melting point of SO2(s)? d. Suppose you start with a sample of SO 2 at 0.5 atm and -50°C, and decrease the pressure to 0.001 atm while maintaining the temperature at -50°C. What phase changes, if any, will occur? e. What acid do you expect to form if SO 2(g) is dissolved in water? ____________________ Explain your reasoning.
At 100oC and 1 atm, water is in which phase?a. solidb. liquidc. gasd. supercritical fluide. solid-liquid equilibriumf. liquid-gas equilibriumg. solid-gas equilibrium
Consider this phase diagram for carbon. Which phases are present at the lower triple point?a. diamondb. graphitec. gasd. liquid 
Could you measure the triple point of water by measuring the temperature in a vessel in which water vapor, liquid water, and ice are in equilibrium under one atmosphere of air?
Consider this phase diagram for carbon dioxide in what phase is CO 2 at 4 atm and -10 °C? a. Solid b. Gas c. Liquid
A phase diagram is a pressure-temperature graph that shows the ranges of temperature and pressure over which each phase is stable. The phase diagram is divided into three regions, each region representing one stable phase: solid, liquid, or gas. There are three boundary lines that separate the phases from one another. These boundary lines represent the equilibrium between two phases. The point at which the three boundary lines intersect is called the triple point. All three phases can exist in equilibrium with each other at this point. Use the phase diagram for CO 2 and determine which of the following statements are correct. SELECT ALL THAT APPLY. All three phases of CO2 exist simultaneously at the triple point. When the pressure is 1 atm, there is no temperature at which the liquid phase of CO  2 exists. CO2 forms a supercritical fluid at temperatures less than 31 degrees Celsius. CO2 is a gas under normal conditions of temperature and pressure. Movement across boundary line BO corresponds to a phase change. When the pressure is 4 atm and the temperature is more than -56.7 degrees Celsius, CO  2 exists as a solid.
Consider the following phase diagram and identify the process occurring as one goes from point C to point D. a. increasing temperature with a phase change from liquid to vapor b. increasing temperature with a phase change from solid to liquid c. increasing temperature with no phase change d. increasing temperature beyond the critical point e. increasing temperature with a phase change from solid to vapor
What is the process where molecules go directly from the solid phase to the gas phase? a. sublimation b. melting c. condensation d. deposition e. freezing
The direct change of a substance from a solid to a gas is called ____.a. evaporationb. sublimationc. condensationd. solidification
Superman can squeeze graphite (coal) to such a high pressure that it is transformed to diamond. Let’s consider this claim against the underlying science. The phase diagram for carbon is shown below. What pressure does Superman need to exert to change graphite into diamond at room temperature?
Consider the phase diagram below.How many distinct solid phases are depicted?1. 12. 33. 44. 2
According to Figure 1, what is the normal boiling point of Xe?A. < 152 KB. 161 KC. 152 KD. 166 KE. > 166 K
Consider the phase diagram below.  If the dashed line at 1 atm of pressure is followed from 100 to 500°C, what phase changes will occur (in order of increasing temperature)? A) condensation, followed by vaporization B) sublimation, followed by deposition C) vaporization, followed by deposition D) fusion, followed by vaporization E) No phase change will occur under the conditions specified.
Sketch the phase diagram:Which of the following statements is true about the phase diagram above?I. The solid is denser than the liquid.II. The melting point of the solid decreases as pressure is increased.III. Line AB represents fusion.IV. As the temperature is decreased from 200°C to 0°C at 0.9 atm, two phase changes occur.V. As the pressure is increased from 0.003 atm to 14 atm at 25°C, one phase change occurs.a) I, IIb) I, IVc) II, IVd) II, Ve) IV, V
What factors cause changes between the liquid and gas state? Check all that apply.   a. A gas can be converted into a liquid by decreasing the pressure of a gas sample. b. A liquid can be converted to a gas by heating. c. A gas can be converted into a liquid by increasing the pressure of a gas sample. d. A liquid can be converted to a gas by cooling. e. A gas can be converted into a liquid by cooling. f. A gas can be converted into a liquid by heating.
What factors cause changes between the solid and liquid state? Check all that apply. a. A solid can be converted to a liquid by cooling. b. A liquid can be converted to a solid by cooling. c. A solid can be converted to a liquid by heating. d. A liquid can be converted to a solid by heating.  
Enter the critical temperature of water. 
The phase diagram for xenon is shown below.(b) Describe the phase changes that a sample of xenon undergoes at −115°C as it is compressed from 0.5 atm to 25 atm. (The critical pressure of xenon is 58 atm.)
Sulfur exhibits two solid phases, rhombic and monoclinic. Use the accompanying phase diagram for sulfur to answer the following questions. (The phase diagram is not to scale.)How many triple points are in the phase diagram?
Sulfur exhibits two solid phases, rhombic and monoclinic. Use the accompanying phase diagram for sulfur to answer the following questions. (The phase diagram is not to scale.)What phases are in equilibrium at each of the triple points?
Sulfur exhibits two solid phases, rhombic and monoclinic. Use the accompanying phase diagram for sulfur to answer the following questions. (The phase diagram is not to scale.)What is the stable phase at 1 atm and 100. ˚C?
Sulfur exhibits two solid phases, rhombic and monoclinic. Use the accompanying phase diagram for sulfur to answer the following questions. (The phase diagram is not to scale.)What are the normal melting point and the normal boiling point of sulfur?
Sulfur exhibits two solid phases, rhombic and monoclinic. Use the accompanying phase diagram for sulfur to answer the following questions. (The phase diagram is not to scale.)Which is the densest phase?
Sulfur exhibits two solid phases, rhombic and monoclinic. Use the accompanying phase diagram for sulfur to answer the following questions. (The phase diagram is not to scale.)At a pressure of 1.0 x 10 -5 atm, can rhombic sulfur sublime?
Sulfur exhibits two solid phases, rhombic and monoclinic. Use the accompanying phase diagram for sulfur to answer the following questions. (The phase diagram is not to scale.)What phase changes occur when the pressure on a sample of sulfur at 100. ˚C is increased from 1.0 x 10-8 atm to 1500 atm?
Use Figure 12.10 to answer the following:(a) Carbon dioxide is sold in steel cylinders under a pressure of approximately 20 atm. Is there liquid CO2 in the cylinder at room temperature (∼20°C)? At 40°C? At −40°C? At −120°C?
Use the accompanying phase diagram for carbon to answer the question below.How many triple points are in the phase diagram?
Use Figure 12.10 to answer the following:(b) Carbon dioxide is also sold as solid chunks, called dry ice, in insulated containers. If the chunks are warmed by leaving them in an open container at room temperature, will they melt?
Use the accompanying phase diagram for carbon to answer the question below.What phases can coexist at each triple point?
Use the accompanying phase diagram for carbon to answer the question below.What happens if graphite is subjected to very high pressures at room temperature?
Use Figure 12.10 to answer the following:(c) If a container is nearly filled with dry ice and then sealed and warmed to room temperature, will the dry ice melt?
Use the accompanying phase diagram for carbon to answer the question below.If we assume that the density increases with an increase in pressure, which is more dense, graphite or diamond?
Like most substances, bromine exists in one of the three typical phases. Br  2 has a normal melting point of -7.2 ˚C and a normal boiling point of 59 ˚C. The triple point for Br2 is -7.3 ˚C and 40 torr, and the critical point is 320 ˚C and 100 atm. Using this information, sketch a phase diagram for bromine indicating the points described above. Based on your phase diagram, order the three phases from least dense to most dense. What is the stable phase of Br2 at room temperature and 1 atm? Under what temperature conditions can liquid bromine never exist? What phase changes occur as the temperature of a sample of bromine at 0.10 atm is increased from -50 ˚C to 200 ˚C?
Use Figure 12.10 to answer the following:(d) If dry ice is compressed at a temperature below its triple point, will it melt?
The melting point of a fictional substance X is 225 ˚C at 10.0 atm. If the density of the solid phase of X is 2.67 g/cm3 and the density of the liquid phase is 2.78 g/cm 3 at 10.0 atm, predict whether the normal melting point of X will be less than, equal to, or greater than 225 ˚C. Explain.
Consider the following data for xenon:Triple point:                       -121 ˚C, 280 torrNormal melting point:       -112 ˚CNormal boiling point:        -107 ˚CWhich is more dense, Xe(s) or Xe(l)? How do the melting point and boiling point of xenon depend on pressure?
Explain why an egg cooks more slowly in boiling water in Denver than in New York City. (Hint: Consider the effect of temperature on reaction rate and the effect of pressure on boiling point.)
Nitrogen has a normal boiling point of 77.3 K and a melting point (at 1 atm) of 63.1 K. Its critical temperature is 126.2 K and critical pressure is 2.55 104 torr. It has a triple point at 63.1 K and 94.0 torr.Sketch the phase diagram for nitrogen to answer if nitrogen has a stable liquid phase at 1 atm.
Argon has a normal boiling point of 87.2 K and a melting point (at 1 atm) of 84.1 K. Its critical temperature is 150.8 K and critical pressure is 48.3 atm. It has a triple point at 83.7 K and 0.68 atm.Sketch the phase diagram to answer whether solid argon or liquid argon has the greater density?
The critical point of NH 3 is 132 ˚C and 111 atm, and the critical point of N 2 is -147 ˚C and 34 atm. Which of these substances cannot be liquefied at room temperature no matter how much pressure is applied? Explain.
The phase diagram of a hypothetical substance is shown below.Estimate the normal boiling point of the substance.
The phase diagram of a hypothetical substance is shown below.What is the physical state of the substance under T = 150 K, P = 0.2 atm?
Carbon tetrachloride displays a triple point at 249.0 K and a melting point (at 1 atm) of 250.3 K.Which phase of carbon tetrachloride is more dense, the solid or the liquid?
The phase diagram of a hypothetical substance is shown below.What is the temperature of the substance at the triple point?
The phase diagram of a hypothetical substance is shown below.Estimate the normal freezing point of the substance.
The phase diagram of a hypothetical substance is shown below.What is the physical state of the substance under T = 100 K, P = 0.8 atm?
The phase diagram of a hypothetical substance is shown below.What is the physical state of the substance under T = 300 K , P = 1.0 atm?
The phase diagram of a hypothetical substance is shown below.What is the pressure of the substance at the triple point?
Describe the phase changes that occur when the temperature of CO2 is increased from 190 K to 350 K at a constant pressure of 5.1 atm.
Describe the phase changes that occur when the temperature of CO2 is increased from 190 K to 350 K at a constant pressure of 10 atm.
Describe the phase changes that occur when the temperature of CO2 is increased from 190 K to 350 K at a constant pressure of 100 atm.
Refer to the figure, and describe all the phase changes that would occur in each of the following cases:Water vapor originally at 0.005 atm and –0.5˚C is slowly compressed at constant temperature until the final pressure is 20 atm.
Refer to the figure, and describe all the phase changes that would occur in each of the following cases:Water originally at 100.0˚C and 0.50 atm is cooled at constant pressure until the temperature is –10˚C.
Referring to Figure 11.29, describe the phase changes (and the temperatures at which they occur) when CO2 is heated from –80 to –20°C at a constant pressure of 3 atm.
Referring to Figure 11.29, describe the phase changes (and the temperatures at which they occur) when CO2 is heated from –80 to –20°C at a constant pressure of 6 atm.
Use the phase diagram for neon to answer the following questions:At temperature T  =-100 oC can neon be liquefied by compressing it?
Choose the statements that correctly describe the following phase diagram.a. If the temperature is raised from 50 K to 400 K at a pressure of 1 atm, the substance boils at approximately 185 K.b. The liquid phase of this substance cannot exist under conditions of 2 atm at any temperature.c. The triple point occurs at approximately 165 K.d. At a pressure of 1.5 atm, the melting point of the substance is approximately 370 K.e. The critical point occurs at approximately 1.7 atm and 410 K.
Synthetic diamonds are made under conditions of high temperature (2000 K) and high pressure (1010 Pa; 105 atm) in the presence of catalysts. Carbon’s phase diagram is useful for finding the condition for formation of natural and synthetic diamonds. Along the diamond-graphite line, the two allotropes are in equilibrium.(a) At point A, what is the sign of ΔH for the formation of diamond from graphite? Explain.
Synthetic diamonds are made under conditions of high temperature (2000 K) and high pressure (1010 Pa; 105 atm) in the presence of catalysts. Carbon’s phase diagram is useful for finding the condition for formation of natural and synthetic diamonds. Along the diamond-graphite line, the two allotropes are in equilibrium.(b) Which allotrope is denser? Explain.
Bismuth is used to calibrate instruments employed in high-pressure studies because it has several well-characterized crystalline phases. Its phase diagram (below) shows the liquid phase and five solid phases that are stable above 1 katm (1000 atm) and up to 300°C. Which solid phases are stable at 25°C?
Bismuth is used to calibrate instruments employed in high-pressure studies because it has several well-characterized crystalline phases. Its phase diagram (below) shows the liquid phase and five solid phases that are stable above 1 katm (1000 atm) and up to 300°C. Which phase is stable at 50 katm and 175°C?
Figure 12.11 shows the phase changes of pure water. Consider how the diagram would change if air were present at 1 atm and dissolved in the water.(a) Would the three phases of water still attain equilibrium at some temperature? Explain.
Figure 12.11 shows the phase changes of pure water. Consider how the diagram would change if air were present at 1 atm and dissolved in the water.(a) Would the three phases of water still attain equilibrium at some temperature? Explain.(b) In principle, would that temperature be higher, lower, or the same as the triple point for pure water? Explain.
Bismuth is used to calibrate instruments employed in high-pressure studies because it has several well-characterized crystalline phases. Its phase diagram (below) shows the liquid phase and five solid phases that are stable above 1 katm (1000 atm) and up to 300°C. As the pressure is reduced from 100 to 1 katm at 200°C, what phase transitions does bismuth undergo?
Figure 12.11 shows the phase changes of pure water. Consider how the diagram would change if air were present at 1 atm and dissolved in the water.(c) Would ice sublime at a few degrees below the freezing point under this pressure? Explain.
What is the normal boiling point of this compound?  
Bismuth is used to calibrate instruments employed in high-pressure studies because it has several well-characterized crystalline phases. Its phase diagram (below) shows the liquid phase and five solid phases that are stable above 1 katm (1000 atm) and up to 300°C. What phases are present at each of the triple points?
From the phase diagram for water (Figure 10.31), determine the state of water at: (a) 35 °C and 85 kPa
The density of liquid NH3 is 0.64 g/mL; the density of gaseous NH3 at STP is 0.0007 g/mL. Explain the difference between the densities of these two phases.
In terms of their bulk properties, how do liquids and solids differ? How are they similar?
In terms of the kinetic molecular theory, in what ways are liquids similar to solids? In what ways are liquids different from solids?
In terms of the kinetic molecular theory, in what ways are liquids similar to gases? In what ways are liquids different from gases?
Explain why liquids assume the shape of any container into which they are poured, whereas solids are rigid and retain their shape.
Use the phase diagram of neon  to answer the following questions.What is the approximate value of the normal boiling point?
Use the phase diagram of neon  to answer the following questions.What can you say about the strength of the intermolecular forces in neon and argon based on the critical points of Ne and Ar? (critical temperature (Ar) = 150.9  K, critical pressure (Ar) = 48.0  atm)
The fact that water on Earth can readily be found in all three states (solid, liquid, and gas) is in part a consequence of the fact that the triple point of water (T = 0.01 , P = 0.006 atm) falls within a range of temperatures and pressures found on Earth. Saturns largest moon, Titan, has a considerable amount of methane in its atmosphere. The conditions on the surface of Titan are estimated to be P = 1.6 atm and T = -178 . As seen from the phase diagram of methane given below, these conditions are not far from the triple point of methane, raising the tantalizing possibility that solid, liquid, and gaseous methane can be found on Titan.In what state would you expect to find methane on the surface of Titan?
The fact that water on Earth can readily be found in all three states (solid, liquid, and gas) is in part a consequence of the fact that the triple point of water (T = 0.01 , P = 0.006 atm) falls within a range of temperatures and pressures found on Earth. Saturns largest moon, Titan, has a considerable amount of methane in its atmosphere. The conditions on the surface of Titan are estimated to be P = 1.6 atm and T = -178 . As seen from the phase diagram of methane given below, these conditions are not far from the triple point of methane, raising the tantalizing possibility that solid, liquid, and gaseous methane can be found on Titan.On moving upward through the atmosphere, the pressure will decrease. If we assume that the temperature of -178 oC does not change or fluctuate, what phase change would you expect to see as we move away from the surface?
The triple point of air-free water is defined as 273.16 K. Why is it important that the water be free of air?
From the phase diagram for water (Figure 10.31), determine the state of water at: (b) −15 °C and 40 kPa
Naphalene, (C10H8) is the main ingredient in traditional mothballs. Its normal melting point is 81˚C, its normal boiling point is 218˚C, and its triple point is 80˚C at 1000 Pa.Using the data, construct a phase diagram for naphthalene, labeling all the regions.
From the phase diagram for water (Figure 10.31), determine the state of water at: (c) −15 °C and 0.1 kPa
From the phase diagram for water (Figure 10.31), determine the state of water at: (d) 75 °C and 3 kPa
From the phase diagram for water (Figure 10.31), determine the state of water at: (e) 40 °C and 0.1 kPa
From the phase diagram for water (Figure 10.31), determine the state of water at: (f) 60 °C and 50 kPa
What phase changes will take place when water is subjected to varying pressure at a constant temperature of 0.005 °C? At 40 °C? At −40 °C?
Pressure cookers allow food to cook faster because the higher pressure inside the pressure cooker increases the boiling temperature of water. A particular pressure cooker has a safety valve that is set to vent steam if the pressure exceeds 3.4 atm. What is the approximate maximum temperature that can be reached inside this pressure cooker Explain your reasoning.
Consider the phase diagram shown below.A sample of the substance in the phase diagram is initially at 181 oC and 931 mmHg. What phase transition occurs when the pressure is decreased to 761 mmHg at constant temperature?
From the phase diagram for carbon dioxide in Figure 10.34, determine the state of CO2 at: (a) 20 °C and 1000 kPa
Kyanite, sillimanite, and andalusite all have the formula Al 2SiO5. Each is stable under different conditions (see the graph below). At the point where the three phases intersect:(d) Which mineral, if any, has the lowest density?
From the phase diagram for carbon dioxide in Figure 10.34, determine the state of CO2 at: (b) 10 °C and 2000 kPa
From the phase diagram for carbon dioxide in Figure 10.34, determine the state of CO2 at: (c) 10 °C and 100 kPa
From the phase diagram for carbon dioxide in Figure 10.34, determine the state of CO2 at: (d) −40 °C and 500 kPa
Determine the phase changes that carbon dioxide undergoes as the pressure changes if the temperature is held at −50 °C? If the temperature is held at −40 °C? At 20 °C? (See the phase diagram in Figure 10.34.)
If a severe storm results in the loss of electricity, it may be necessary to use a clothesline to dry laundry. In many parts of the country in the dead of winter, the clothes will quickly freeze when they are hung on the line. If it does not snow, will they dry anyway? Explain your answer.
Is it possible to liquefy nitrogen at room temperature (about 25 °C)? Is it possible to liquefy sulfur dioxide at room temperature? Explain your answers.
Elemental carbon has one gas phase, one liquid phase, and two different solid phases, as shown in the phase diagram:(a) On the phase diagram, label the gas and liquid regions.
Elemental carbon has one gas phase, one liquid phase, and two different solid phases, as shown in the phase diagram:(b) Graphite is the most stable phase of carbon at normal conditions. On the phase diagram, label the graphite phase.
Elemental carbon has one gas phase, one liquid phase, and two different solid phases, as shown in the phase diagram:(c) If graphite at normal conditions is heated to 2500 K while the pressure is increased to 1010 Pa, it is converted into diamond. Label the diamond phase.
Elemental carbon has one gas phase, one liquid phase, and two different solid phases, as shown in the phase diagram:(d) Circle each triple point on the phase diagram.
Elemental carbon has one gas phase, one liquid phase, and two different solid phases, as shown in the phase diagram:(e) In what phase does carbon exist at 5000 K and 108 Pa?
Elemental carbon has one gas phase, one liquid phase, and two different solid phases, as shown in the phase diagram:(f) If the temperature of a sample of carbon increases from 3000 K to 5000 K at a constant pressure of 106 Pa, which phase transition occurs, if any?
The boiling point of amphetamine, C 9H13N, is 201°C at 760 torr and 83°C at 13 torr. What is the concentration (in g/m3) of amphetamine when it is in contact with 20.°C air?
Consider the phase diagram for iodine shown below and answer each of the following questions.What is the normal boiling point for iodine?
Consider the phase diagram for iodine shown below and answer each of the following questions.What is the melting point for iodine at 1 atm?
Consider the phase diagram for iodine shown below and answer each of the following questions.What phase is present at room temperature and normal atmospheric pressure?
Consider the phase diagram for iodine shown below and answer each of the following questions.What phase is present at 186 oC and 1.0 atm?
The density of solid gallium at its melting point is 5.9 g/cm3, whereas that of liquid gallium is 6.1 g/cm3. Is the temperature at the triple point higher or lower than the normal melting point? Is the slope of the solid-liquid line for gallium positive or negative?
The types of intermolecular forces in a substance are identical whether it is a solid, a liquid, or a gas. Why then does a substance change phase from a gas to a liquid or to a solid?
Based on the phase diagram for methane below, what happens to methane as it is heated from −250 oC to 0 oC at a pressure of 10-2 atm?
Use these data to draw a qualitative phase diagram for ethylene (C2H4). Is C2H4(s) more or less dense than C2H4(l)?bp at 1 atm:        −103.7°Cmp at 1 atm:       −169.16°CCritical point:        9.9°C and 50.5 atmTriple point:       −169.17°C and 1.20 x 10−3 atm
Consider the phase diagram for carbon dioxide.If you have carbon dioxide at 1.5 atm and 26˚C, could you make it a liquid by cooling it down?
Use these data to draw a qualitative phase diagram for H2. Does H2 sublime at 0.05 atm? Explain.mp at 1 atm:                                         13.96 Kbp at 1 atm:                                          20.39 KTriple point:                                          13.95 K and 0.07 atmCritical point:                                        33.2 K and 13.0 atmVapor pressure of solid at 10 K:          0.001 atm
Consider the phase diagram for carbon dioxide.How could you make it a liquid at 26˚C?
Consider the phase diagram for carbon dioxide.If you increase the pressure of carbon dioxide that is at body temperature (37˚C), will it ever liquefy?
The phase diagram for sulfur is shown below.(a) Give a set of conditions under which it is possible to sublime the rhombic form of solid sulfur.
The phase diagram for sulfur is shown below.(b) Describe the phase changes that a sample of sulfur undergoes at 1 atm when it is heated from 90°C to 450°C.
Which of the following statements is NOT correct? a. As a liquid is heated at a constant pressure above the critical pressure, it eventually changes to the gas phase. b. It is possible to find a path such that a liquid can be converted to a gas without a phase change. c. Increasing the pressure of a fluid at a constant temperature above the critical temperature produces no phase change no matter how great the pressure becomes. d. Below the critical temperature both the liquid and gas phase can exist. Higher pressure favors the liquid phase.
The density of a substance is greater in its solid phase than in its liquid phase.If the triple point in the phase diagram of the substance is below 1.0 atm, then which will necessarily be at a lower temperature, the triple point or the normal melting point?
When a liquid is in dynamic equilibrium with its vapor in a closed container:(a) the rate at which molecules from the liquid phase enter the gas phase exactly equals the rate at which molecules from the gas phase pass into the liquid.(b) a change in temperature will not change the pressure in the container.(c) the amount of gas in the container must exactly equal the amount of liquid.(d) molecules cannot go from the liquid phase to the gas phase because the amount of liquid in the container is constant.(e) the vapor will gradually change back to the liquid state, that is, no vapor will be left.
At 25 gallium is a solid with a density of 5.91 g/cm3. Its melting point, 29.8 , is low enough that you can melt it by holding it in your hand . The density of liquid gallium just above the melting point is 6.1 g/cm3.Based on this information, what unusual feature would you expect to find in the phase diagram of gallium?
Generic phase diagram for a pure substance. The green line is the sublimation curve, the blue line is the melting curve, and the red line is the vapor-pressure curve.Imagine that the pressure on the solid phase in the figure is decreased at constant temperature. If the solid eventually sublimes, what must be true about the temperature?
The phase diagram for compound X is shown above. You wish to purify a sample of X which was collected at P = 1.0 atm and T = 100 K by subliming it. In order to sublime the sample, you should:(a) Increase P to 1.5 atm and then increase T to 300 K(b) Increase T to 300 K, keeping P at 1.0 atm(c) Lower P to 0.5 atm and then increase T to 250 K(d) Increase T to 300 K and then lower P to 0.5 atm(e) the sample cannot be sublimed
The table below lists the density of O2 at various temperatures and at 1 atm. The normal melting point of O2 is 54 K.Temperature (K)Density (mol/L)6040.17038.68037.29035.61000.1231200.1021400.087Over what temperature range in the table is O2 a gas?
The high-pressure phase diagram of ice is shown at the top of the next column. Notice that, under high pressure, ice can exist in several different solid forms.Would ice III sink or float in liquid water?
Dry ice, CO2(s), does not melt at atmospheric pressure. It sublimes at a temperature of −78 °C. What is the lowest pressure at which CO2(s) will melt to give CO2(l)? At approximately what temperature will this occur? (See Figure 10.34 for the phase diagram.)
During which of the following phase changes must heat be added to overcome intermolecular forces?I. VaporizationII. SublimationIII. DepositionA) I onlyB) II onlyC) I and II onlyD) I and III onlyE) II and III only
Answer the following questions based on the following phase diagram given below.a. At what temperature can we no longer tell the difference between the liquid and the gas? _____________b. Which point represents an equilibrium between the solid, liquid, and gas phase?    _____________c. Which line segment represents an equilibrium between fusion and freezing? _____________d. Which line segment represents an equilibrium between sublimation and deposition? _____________e. Which line segment represents an equilibrium between condensation and vaporization? _____________f. What is the normal freezing point of this unknown substance? _____________g. What is the normal boiling point of this unknown substance? _____________
Which of the following statements is true?A. The triple point of a substance increases when the pressure increases.B. The critical point of a substance decreases when the temperature increases.C. Both the triple point and the critical point of a substance increase with a decrease in temperature.D. Both the triple point and the critical point of a substance are dependent on the substance only, but not on temperature or pressure.E. None of the above are true.
Starting at Point A on the Phase Diagram (where CO2 coexists as a solid and liquid), if the pressure is steadily decreased all the way to 1.0 atm, but the temperature is maintained constant, what will happen to the CO2?A) It will freeze into a solidB) It will melt into a liquidC) It will melt into a liquid which will then be converted into a gasD) It will become a supercritical fluidE) It will melt into a liquid but eventually converted into solid, gas, and liquid simultaneously
For the choices below, what is the normal boiling point of this substance? 1. 230°C2. 100°C3. 200°C4. 150°CWhat is the critical pressure for this substance?1. 50 atm2. 0.08 atm3. 44 atm4. 25 atm5. 1 atm6. >100 atm
The high-pressure phase diagram of ice is shown at the top of the next column. Notice that, under high pressure, ice can exist in several different solid forms .What three forms of ice are present at the triple point marked O?
Which point on the phase diagram represents the triple point of CO2?A) AB) BC) CD) DE) X
Choose the answer that correctly assigns the labels on the phase.A) A = liquid, B = gas, C = solid, D = triple pointB) A = gas, B = liquid, C = solid, D = critical pointC) A = liquid, B = solid, C = gas, D = critical pointD) A = gas, B = solid, C = liquid, D = triple pointE) A = solid, B = gas, C = liquid, D = supercritical fluid
The phase diagram for xenon is shown below:In what phase is xenon found at room temperature and 1.0 atm pressure?
The phase diagram for xenon is shown below:If the pressure exerted on a xenon sample is 0.75 atm, and the temperature is -114°C, in what phase does xenon exist?
The phase diagram for xenon is shown below:If you measure the equilibrium vapor pressure of a liquid xenon sample to be 380 mm Hg, what is the temperature of the liquid phase?
The phase diagram for xenon is shown below:What phase change occurs if the temperature at 0.35 atm drops from -118 to -124°C?
The phase diagram for xenon is shown below:Which is the denser phase; solid or liquid? Explain your answer.
What borderline in a phase diagram will have the steepest slope?A. solid-gas B. solid-liquid C. liquid-gas D. vapor-solid E. cannot determine
If the phase diagram for a pure substance has two and only two solid phases, how many critical points will it have?A. 0 B. 1 C. 2 D. 3 E. 4
If the phase diagram for a pure substance has two and only two solid phases, how many triple points will it have?A. 0 B. 1 C. 2 D. 3 E. 4
The phase diagram for sulfur is shown below. The rhombic and monoclinic phases are two solid phases.Below what pressure will solid sulfur sublime?Express your answer using two significant figures.
The phase diagram for SO2 is shown here.At which of the three points marked in red does SO2(g) most closely approach ideal-gas behavior?
From the phase diagram for carbon dioxide in Figure 10.34, determine the state of CO2 at: (e) −80 °C and 1500 kPa.
Below is a phase diagram for a substance. What is the name for point Z on the diagram? (A) boiling point. (B) critical point. (C) triple point. (D) normal boiling point. (E) melting point. 
The phase diagram for xenon is shown below.(a) What phase is xenon in at room temperature and pressure?
Evaporation is: Select one:a. a cooling process for humans when they sweat. b. All of these c. increased by increasing temperature. d. an endothermic process. e. the opposite process as condensation.
Consider the phase diagram given below. What phases are present at points A through H? Identify the triple point, normal boiling point, normal freezing point, and critical point. Which phase is denser, solid or liquid?
Use the phase diagram for neon to answer the following questions:What is the approximate value of the normal melting point?
Use the phase diagram for neon to answer the following questions:Below what pressure value will solid neon sublime?