Chemistry Chapter: Vapor Pressure and Raoult's Law

Questions and Answers

What is the relationship between vapor pressure and the mole fraction of a component in a solution according to Raoult's law?

Vapor pressure is inversely proportional to the mole fraction.

Vapor pressure is directly proportional to the mole fraction. (correct)

Vapor pressure is unrelated to the mole fraction.

Vapor pressure depends on the temperature only.

Which statement accurately describes volatile and non-volatile substances?

Volatile substances do not produce vapor, while non-volatile substances produce vapor.

Only non-volatile substances produce vapor in a solution.

Both volatile and non-volatile substances produce vapor.

Volatile substances produce vapor, while non-volatile substances do not produce vapor. (correct)

What is indicated by the formula $P_A = P_A^o imes X_A$?

The vapor pressure is equal to the sum of all components in the solution.

The vapor pressure of a pure substance is the same as that of a solution.

The vapor pressure of a component in a solution depends on the vapor pressure of the pure component and its mole fraction. (correct)

The vapor pressure is solely determined by the temperature of the substance.

What happens to the vapor pressure of a solution when non-volatile solutes are added?

<p>Vapor pressure decreases due to the presence of solute.</p> Signup and view all the answers

What does $K_g = P_A - P_S$ represent in the context of vapor pressure?

<p>The lowering of vapor pressure due to solute presence.</p> Signup and view all the answers

Study Notes

Escaping Tendency & Vapour

Intermolecular forces exist between liquid and its vapor, influencing how substances transition between states.
Escaping tendency refers to the propensity of molecules to move from the liquid phase to the vapor phase.
Volatile substances readily produce vapor, while non-volatile substances do not produce vapor under the same conditions.

Raoult's Law

The vapor pressure (V.P) of a component in a solution is directly proportional to its mole fraction within that solution.
This relationship is fundamental for understanding how mixtures behave compared to pure components.

Formula

The formula ( P_A = P_A^o \cdot X_A ) represents the vapor pressure of component A in a solution, where ( P_A^o ) is the vapor pressure of pure A, and ( X_A ) is its mole fraction in the solution.

Vapor Pressure Comparison

The vapor pressure of a pure substance is always greater than that of a solution comprising that substance.
The equation ( P_o = P_A \cdot X_A + P_B \cdot X_B ) illustrates how the total vapor pressure of a solution is affected by the concentrations of its components.

Non-Volatile Solutes

For solutions containing non-volatile solutes:
- ( K_g = P_A - P_S ) defines the difference between the vapor pressure of the solvent and that in the solution.
- ( P_S = P_K \cdot X_A ) relates to the vapor pressure of the solvent in the presence of the solute.
Lowering the vapor pressure is quantified by the equation ( P_A - P_S ), known as the relative lowering of vapor pressure (R.L.V.P).

Description

This quiz covers important concepts related to vapor pressure, including the escaping tendency of liquids, volatile and non-volatile substances, and Raoult's law. Test your understanding of key equations and principles that govern the behavior of components in solutions. Prepare to explore how vapor pressure changes with the composition of solutions.