AP CHEM solutions Distillation is a separation technique used to purify liquids based on differences in their boiling points. It leverages the fact that in a mixture, each component will exert its own vapor pressure, and the more volatile component (the one with the lower boiling point) will have a higher vapor pressure.

Basic Principles

• vapor pressure: vapor pressure The pressure exerted by a vapor in thermodynamic equilibrium with its condensed phases (liquid or solid) at a given temperature in a closed system.
• Boiling Point: The temperature at which the vapor pressure of a liquid equals the external pressure surrounding the liquid.
• partial pressure: In a mixture of gases, each gas exerts its own partial pressure. The total pressure is the sum of the partial pressures of all the gases present.
• Raoults Law: Raoults Law For an ideal solution, the partial pressure of each component is equal to the product of the pure component’s vapor pressure and its mole fraction in the liquid mixture. Mathematically:

$$ P_A = x_A P_A^* $$

where:

• $ P_A $ is the partial pressure of component A
• $ x_A $ is the mole fraction of component A in the liquid phase
• $ P_A^* $ is the vapor pressure of pure component A

Simple Distillation

Simple distillation is effective for separating liquids with significantly different boiling points (generally a difference of at least 25°C). The mixture is heated, and the more volatile component vaporizes first. The vapor is then cooled and condensed back into a liquid, which is collected separately.

Fractional Distillation

Fractional distillation is used to separate liquids with closer boiling points. It employs a fractionating column, which provides a large surface area for multiple condensation and vaporization cycles. As the vapor rises through the column, it repeatedly condenses and re-vaporizes. With each cycle, the vapor becomes richer in the more volatile component. This process effectively creates a temperature gradient along the column, allowing for finer separation. Used in making that sweet dino juice !1(https://www.chemicals.co.uk/wp-content/uploads/2021/11/Fractional-[Distillation](./../distillation/)-1-1.png)

Limitations of Distillation

• Azeotropes: Azeotropes Some mixtures form Azeotropes, which are constant boiling mixtures that cannot be separated by simple distillation.
• Heat sensitive compounds: Some compounds decompose at high temperatures, making distillation unsuitable.
• Energy intensive: Distillation can be an energy-intensive process, especially for large-scale operations.

This outline provides a calculus AB level overview of distillation. The bracketed terms represent topics that could benefit from their own separate explanations, particularly focusing on the underlying principles and calculations involved.