Reading Quiz

Question 1:

Answer:

1. A phase transition, or phase transformation, is a discontinuous change in the properties of a substance, as its environment changes very little. A phase diagram plots these phase changes as lines on a graph of temperature vs. pressure.
2. A phase transition is the change in a substance from one form (phase really) to another where "form" refers to conditions in which the substance has similar properties. A phase diagram depicts the conditions of temperature and pressure under which equilibria exist between two phases.
3. "A phase transformation (transition) is a discontinuous change in the properties of a substance, as its invrionment is changed only infinitesimally." "A graph showing the equilibrium phases as a function of temperature and pressure is called a phase diagram" (pg 166)
4. a phase transition is a dicontinuous change in the properties of a substance. A phase diagram is a graph showing the equilibrium phases as a function of temperature and pressure.
5. phase transition - a discontinuous change in the properties of a substance as its environment is changed only infintesimitally. phase diagram - graph showing the equilibrium phases as a function of temperature and pressure
6. A phase transition is a change in the properties of a system with only an infinitesimal change in its state. A phase diagram is a graph showing which regions of a P vs. T graph exist in which phase.
7. A phase transition is a discontinuous change in the properties of a substance, as its environment changes only infinitesimally. A phase diagram is a graph showing the equilibrium phases as a function of temperature and pressure.
8. A discontinuous change in the properties of a substance as it's surroudings are slightly varried. Like ice melting. A phase diagram shows the equilibrium phases as a function of temperature and pressure.
9. A phase transition can be thought of as a sharp (discontinuous) change in the properties of a substance while the environment is actually changed very little. A phase diagram shows the equilibrium phases as a function of temperature and pressure.
10. A phase transition is a discontinuous change in the properties of a substance when the environment is changed only slightly. A phase diagram is a graph of what the stable phase is for a substance at specific values of temperature and pressure (or whatever properties determine the phase).
11. "A discontinuous change in the properties of a substance", like from solid to liquid. A graph showing the equilibrium temperatures and pressures of a substance.

Question 2:

Answer:

1. A triple point is where the solid, liquid, and gas forms of a substance can all coexist simultaneously. For water, the temperature of the triple point is 0.01 degrees Celsius, and the pressure is 0.006 bar.
2. The triple point is the temperature and pressure where three phases (solid, liquid, gas) can coexist. For water, 0.01 °C and 0.006 bar.
3. A triple point occurs at a specific temperature and pressure (for water, T=0.01 degrees C, P=0.006 bar) where the three phases of solid, liquid, and gas can coexist.
4. a region where all 3 phases of a substance can coexist. For water it is at .01C and .006 bar.
5. triple point - the temperature and pressure in which all three phases (liquid, solid, gas) can coexist for water: T = 0.01 C, P = 0.006 bar
6. A triple point is the temperature and pressure where gas, liquid, and solid can all coexist. The triple point of water has T=0.01 C and P=0.006 bars.
7. The point on a phase diagram (a specific temperature and pressure) where all three phases can coexist is the triple point. For water, the triple point is T=0.01 degrees C and P=0.006 bar.
8. Where [all] three phases can coexist at once. For water this is at 0.01 C and 0.006 bar
9. A triple point is a point at which gas, liquid, and solid phases of a substance can all coexist at the same temperature and pressure. The tripple point of water occurs at 0.01 deg C and 0.006 bar.
10. A triple point is the point at which all three phases (solid, liquid, gas) of a substance can coexist stably. The triple point of water is at 0.01 degrees Celsius and 0.006 bar of pressure.
11. A point at which all three phases can coexist. T=0.01 C P=0.006 bar

Question 3:

Answer:

1. A critical point is the point where there is no longer any difference in between liquid and gas. With water, this happens at 374 degrees Celsius and 221 bars.
2. The critical point is the temperature and pressure above which there is no distinction between liquid and vapor. The substance exists as a supercritical fluid. For water, 374 °C and 221 bar
3. A critical point is a specific temperature and pressure where a discontinuous change between liquid and gas stops existing. For water, this point occurs at 374 degrees C and 221 bars.
4. A point where there is no longer any discontinuous change between the gas and liquid phases. For water this occurs at 374c and 74 bars.
5. critical point - a temperature and pressure above which there is no longer any discontinuous change from liquid to gas for water: T = 374 C, P = 221 bar
6. A critical point is where there is no longer a phase transition. The critical point of water has T=374 C and P=221 bars.
7. A critical point is the point at which there is no longer any discontinuous change from liquid to gas. For water, the critical point occurs at T=374 degrees C and P=221 bars.
8. This is where there is no real change between a liquid and a gas. I assume you mean what's the critical point of water, and that is 374 C and 221 bars.
9. A critical point is the point at which the transition from gas to liquid and vice versa is no longer discontinuous, because the properties of the two under the conditions are very similar. The critical point of water occurs at 374 deg C and 221 bar.
10. The critical point is the point at which the difference between the liquid and gas phase of a substance is no longer distinct - there is no abrupt change from one phase to another, they kind of gradually mold into each other. The critical point of water is 374 degrees Celsius and 221 bars of pressure.
11. When there is no discontinuous change from gas to liquid. 374 C and 221 bars

Question 4:

Answer:

1. At low pressures, the Gibbs free energy of Diamond is higher than that of Graphite, by 2.9 kJ. Diamond is thus likely to spontaneously change into graphite, though extremely slowly. Graphite is more stable at standard pressure because its Gibbs free energy is lower. As the pressure increases, since a mole of graphite has a higher volume than a mole of diamond, its Gibbs free energy increases at a faster rate, until its G is higher than that of diamond. Its slope on the graph is steeper because of this larger V, which makes (delta_G/delta_P) greater.
2. Under atmospheric pressure, G_graphite is lower than G_diamond, so graphite is the stable form. Graphite has a larger molar volume than diamond, so the slope dG/dP is steeper than that of diamond. The point where the lines intersect represents the pressure at which G_diamond becomes less than G_graphite and diamond becomes the stable phase.
3. Since Diamond and Graphite have different molecular structures, they have different free energies. Figure 5.15 shows a graph of the free energies, neglecting volume changes. The more stable form is the form with a lower free energy, and from this graph we can see that at low pressures, Graphite is more stable, and at high pressures, diamonds are more stable.
4. Since volumes do not change the slopes are merely straight lines. Since a volume of a mole of graphite is larger than a mole of diamond, graphite has a steeper slope.
5. The slope of a Gibbs free energy vs. pressure plot is the volume by a Maxwell relation. Since a mole of graphite has a greater volume than a mole of diamond, it's slope is greater. Since a lower Gibbs free energy means greater stability, at low pressures graphite is more stable, and at high pressures (>~15kbar) diamond is more stable. That's why diamonds form at the bottom of the ocean, cool!
6. At standard pressure, graphite has a lower Gibbs free energy and hence is more stable than diamond. As pressure increases, G for diamond increases more slowly than G for graphite. At a pressure of about 15 kilobars, diamond has a lower free energy and hence is more stable. The slopes of the curves are the volume per mole of graphite and diamond, which equals dG/dP by a Maxwell relation.
7. At standard pressure, graphite is more stable than diamond. The slope of the Gibbs free energy vs. Pressure for diamond is less than that for graphite. This means that as the pressure increases, specifically above 15 kilobars, the diamond actually becomes more stable than graphite.
8. At standard pressure Diamond has a higher Gibbs Free energy than does graphite, therefore graphite is more stable and Diamond will turn into graphite (after a while) It seems that diamonds aren't forever afterall. Also Graphite has a steeper curve becase the increase of free energy with respect to pressure is just proportional to the volume, and graphite has a larger volume per mole than does diamond.
9. At standard pressure, the point is that graphite has a lower gibbs free energy than diamonds, and so would be able to provide less work to its surroundings than diamond. It also means that graphite is more stable at lower pressures than diamonds The slope of the curve basically shows that diamonds gain less free energy as they are put under pressure than graphite. It also means that diamonds (eventually) become more stable than graphite, and this is why they form!
10. The slope of graphite is steeper than diamond, which means the Gibbs free energy increases more rapidly as the pressure is increased. Since the more stable phase is the one with the lower Gibbs free energy, graphite is more stable than diamond except at high pressures. Since graphite has more entropy than diamond, its Gibbs free energy decreases faster than that of diamond, as you increase the temperature. So, with increasing temperature, graphite becomes and more and more stable than diamond.
11. It requires very great Pressue and Temperature to form diamond from graphite.

Question 5:

Answer:

1. If you get a ferromagnet hot enough, beyond the Curie temperature, does it stop being a magnet altogether?
3. I don't feel like I have a good conceptual grasp of chemical potential, but perhaps that will get better as I do more problems.
7. This reading seemed pretty straight-forward.
9. n/a
10. Too much chemistry...
11. the diamond grahpite diagram.