Question

1. consider the phase diagram shown here. identify the states present at points a through g.

Explanation:

• Phase diagrams represent the states of a substance (solid, liquid, gas) under different pressure - temperature conditions.
• The critical point is \(P_{c},T_{c}\). Above the critical temperature (\(T > T_{c}\)), the substance is in the super - critical fluid state.
• Below the critical temperature, we distinguish between gas and liquid based on pressure relative to the vapor - pressure curve (the blue curve).
• Point \(a\): Low pressure and low temperature (below critical temperature). In this region, the substance is in the solid state.
• Point \(b\): Pressure is above the vapor - pressure curve (blue curve) and temperature is below \(T_{c}\). So, it is in the liquid state.
• Point \(c\): Pressure is below the vapor - pressure curve and temperature is below \(T_{c}\). So, it is in the gas state.
• Point \(d\): Temperature is above \(T_{c}\). So, it is in the super - critical fluid state.
• Point \(e\): Pressure is above \(P_{c}\) and temperature is below \(T_{c}\). Since it is above the vapor - pressure curve, it is in the liquid state.
• Point \(f\): Lies on the vapor - pressure curve. At the phase - boundary (vapor - pressure curve for liquid - gas), the substance has both liquid and gas phases in equilibrium.
• Point \(g\): Is the triple - point (assuming the general phase - diagram characteristics, although not explicitly labeled as a triple - point in the problem - given diagram, but it is a point on the phase - boundary). At the triple - point, solid, liquid, and gas phases co - exist.

Answer:

• \(a\): Solid
• \(b\): Liquid
• \(c\): Gas
• \(d\): Super - critical fluid
• \(e\): Liquid
• \(f\): Liquid and gas
• \(g\): Solid, liquid, and gas