Physical Transformations of Pure Substances

These flashcards cover key concepts and equations related to the physical transformations and thermodynamic aspects of pure substances, as discussed in the lecture.

What is the relationship between chemical potential and Gibbs free energy in a one-component system?

μ = Gm, where μ is the chemical potential and Gm is the Gibbs free energy.

How does entropy compare among different phases?

In general, Sm (s) < Sm (l) < Sm (g), indicating that solid has the lowest entropy, followed by liquid, and then gas.

What indicates phase stability in terms of chemical potential?

The phase with the lowest chemical potential is stable.

What happens at the temperature Tf and Tb in terms of phases?

Phases are in equilibrium at the temperatures Tf and Tb.

How does increased pressure affect the chemical potential of a substance?

Increased pressure raises the chemical potential.

What is the relationship between Vm (l) and Vm (s) in typical substances?

In most cases, Vm (l) > Vm (s), meaning the molar volume of liquid is greater than that of solid.

What happens to the melting temperature of water when pressure is increased?

For water, Vm (l) < Vm (s); as pressure increases, the melting temperature decreases slightly.

What is the formula relating applied pressure to vapor pressure?

P = P* e^(Vm(l)ΔP / RT), where P* is the vapor pressure without pressure applied.

What is Clapeyron Equation used for?

Clapeyron Equation provides the exact expression for the slope of the tangent to a phase boundary at any point, applicable to any phase equilibrium of any pure substance.

What distinguishes first order phase transitions from second order phase transitions?

First order transitions show a discontinuous derivative of μ with respect to temperature, while second order transitions show a discontinuous second derivative.