Phase Diagram Worksheet

What is a phase diagram primarily a graphical representation of?

• The solubility of a substance at different temperatures.

• The physical states of a substance under different conditions of temperature and pressure.

• The energy changes accompanying chemical reactions.

• The relationship between volume and temperature at constant pressure.

On a typical phase diagram, which phases are most likely to be found in equilibrium along the vapor pressure curve (the red curve)?

• Solid and Liquid

• Liquid and Vapor (Gas)

• Solid, Liquid, and Gas

What specific point on a phase diagram represents the unique condition where the solid, liquid, and gaseous phases of a substance can all coexist in equilibrium?

• Normal Boiling Point

• Critical Point (C)

• Triple Point (T)

• Melting Point

For a substance like water (H₂O), the solid-liquid equilibrium line (melting curve) slopes to the left (backwards). What physical property causes this unusual slope?

• The gas phase is less dense than the liquid phase.

• Liquid water is less dense than solid ice.

• Solid ice is less dense than liquid water.

• Water has very strong intermolecular forces.

• Plasma

• Liquid

• Vapor (Gas)

• Supercritical fluid

Based on the phase diagram for carbon dioxide (CO2), why is solid carbon dioxide commonly known as "dry ice"?

• A. Its triple point is below 1 atm, allowing it to sublime.

• B. Its critical point is easily achievable, making it a liquid.

• C. Its normal melting point is very high.

• D. Its triple point is well above atmospheric pressure (5.11 atm), meaning it sublimes directly from solid to gas at 1 atm.

Referencing the general phase diagram (Pressure vs. Temperature), which region represents the solid phase?

• Low Temperature, Low Pressure

• Low Temperature, High Pressure

• High Temperature, Low Pressure

• High Temperature, High Pressure

The transition of a substance directly from the solid state to the gaseous state, bypassing the liquid state, is known as:

• Melting

• Condensation

• Sublimation

• Deposition

Which phase change describes a substance transitioning from the liquid state to the solid state?

• Melting

• Freezing

According to the lesson, what is one of the important applications of phase diagrams in the pharmaceutical industry?

• Calculating the total energy required to synthesize a drug.

• Determining the color and texture of a drug compound.

• Determining the solubility and stability of drug compounds under various conditions.

• Predicting the toxicity levels of new medicine.