First, it is important to identify what phases are occurring on each side of the line on which Point E rests. In section 1, the pressure is high and the temperature low, meaning the solution is a solid. In section three, both the pressure and temperature are high, meaning the solution is a gas. In other words, the segment that Point E is on is the equilibrium line between solid and gas, thus, deposition and sublimation are occurring at Point E. 

While this may seem like an obscure question, the MCAT specifically requires you to know the shape of the water phase diagram. Unique to only a few molecules, the solid phase in our diagram is less dense than the liquid phase, meaning that the solid/liquid phase line has a negative slope (this can be seen as segment AD in the above image). Water is one of the select few compounds with this characteristic.

The phase diagram for carbon dioxide (CO₂) shows that it will sublimate from a solid to a gas as temperature is increased at one atmosphere of pressure. If a solid immediately goes to a gas, we can conclude that the pressure is too low to allow the substance to first go through the liquid phase. As a result, we can conclude that the point in which CO₂ is in all three phases (the triple point) will take place at a higher pressure than 1atm. Because water (H₂O) is able to go through all of its three phases at a pressure of 1atm, we know that the triple point pressure is less than 1atm.

Section 1 is at high pressure and low temperature, meaning the solution is a solid. In section 2, the solution is at intermediate pressure and temperature, meaning it is a liquid. Section 3 is at high temperature and low pressure, meaning it is a gas. 

Because dry ice is frozen carbon dioxide, it does not have the same liquid-solid equilibrium line as water and traditional ice. Its liquid-solid equilibrium line is positive, which means that increased pressure will only cause the dry ice to remain solid. If it were negative, then increased pressure would cause melting as seen with water. Skating on solids is like skating on dirt or rocks. The other choices concerning solid and gas does not apply since no gases are involved. 

First, find the original area of the hole, in square meters: 

We will also convert the temperatures to Kelvin.

The linear thermal expansion equation is:

Similarly, the thermal expansion of an area is given by the equation:

We are given the value of the constant, we know the original area, and we have the change in temperature. Using these values, we can solve for the change in area.

Find the final area of the hole by adding the change in area to the original area.

There are six possible phase changes between the three phases of matter. Deposition describes the change from gas to solid, while sublimation describes the transition from solid to gas. Freezing (crystallization) is the transition from liquid to solid, while fusion (melting) is the transition from solid to liquid. Condensation is the transition from gas to liquid, while vaporization (boiling) is the transition from liquid to gas.

Low pressure ensures that the molecules are not confined to a more organized state such as liquid or solid, while high temperature means higher kinetic energy, which means that the molecules have more energy to move away from one another and into the gaseous state. Low temperature would mean molecules have less energy to move away from one another, and high pressure will force molecules to be in a more organized state. 

Raining occurs when water vapors become liquid water in the sky. Deposition is the phase change from gas to solid, sublimation is the phase change form solid to gas, and evaporation is the phase change from liquid to gas.

Melting occurs because the skates apply pressure to the ice. Due to the negative slope of solid-liquid equilibrium line for water, increased pressure results in a change from solid to liquid. None of the other answer choices do not have to do with the equilibrium between solid and liquid.