Chemistry - Section on Azeotropes and Distillation

Physical Pharmacy I - Course Information

• Course Code: FAR 221/3
• Lecturer: Dr. Toh Seok Ming
• Academic Session: Semester I, 2014-2015

Lecture 1 - Introduction

• Lecture 1 focused on the introduction to the course.
• Discussion about substances and compounds, categorized into organics and inorganics.
• Discussion on the importance of polarity in categorizing substances and compounds.
• Discussion on intermolecular forces, such as Van der Waals forces (dipole-dipole and London forces), Hydrogen bonding, and covalent and ionic bonds.

Classification of Substances and Compounds

• Chemicals can be classified into organic and inorganic substances.
• Organic compounds contain carbon (C) and are often derived from plants or animals.

Polarity

• Substances and compounds are categorized according to their polarity (very polar, polar, semi-polar, unpolar, very unpolar).
• Polarity influences solubility.

Intermolecular and Chemical Bonding Interactions

• Intermolecular forces, including Van der Waals forces (dipole-dipole, London forces), hydrogen bonding, and other chemical bonding interactions, affect the properties of substances.
• Van der Waals forces are weak attractive forces between molecules.
• Hydrogen bonding is a strong type of intermolecular interaction.
• Chemical bonding (ionic and covalent) is a stronger interaction that holds atoms together in molecules.

Dipole-Dipole Forces

• Polar molecules align themselves in a way that the positive end of one molecule is close to the negative end of another molecule.
• This alignment results in an attractive intermolecular force known as dipole-dipole forces.

London Forces

• Small, instantaneous dipoles occur due to the varying positions of electrons around nuclei in molecules.
• These instantaneous dipoles induce dipoles in neighboring molecules, creating weak attractions known as London forces.

Concept Check - Intermolecular Forces

• London forces are always present in any substance or compound.
• Dipole-dipole forces exist if a molecule is polar.
• Hydrogen bonding occurs when a hydrogen atom is bonded to a highly electronegative atom (O, N, or F).

Concept Check - States of Matter

• The strength of bonds and the distance between molecules determine the state of matter (solid, liquid, or gas).
• In solids, molecules are closely packed and have strong interactions.
• In liquids, molecules are closer than in gases, but there is more movement.
• In gases, molecules are far apart and have weak interactions.

Concept Check - Crystalline and Amorphous Solids

• Crystalline solids have a well-defined, ordered structure.
• Amorphous solids lack a well-defined arrangement of their basic units.

Concept Check - Solutions

• Solutions are homogeneous mixtures of two or more substance.
• Solubility depends on the polarity of solute and solvent.
• Factors affecting solubility include temperature, pressure, and the properties of both solute and solvent.

Concept Check - Solute and Solvent Identification

• Determine the solute(s) and solvent(s) based on the greater composition.
• The component present in the greater amount is the solvent.

Concept Check - Solid Solutions

• A dental filling, made up of liquid mercury and solid silver, is an example of a solid solution.

Solubility

• Solubility is the ability of a substance to dissolve in a solvent.
• Substances that are similar in type will dissolve easily.

Which Compound is More Soluble?

• C4H9OH is more soluble in water than C4H9SH due to stronger hydrogen bonding.

Diffusion

• Diffusion is the movement of molecules, atoms, or ions from an area of higher concentration to an area of lower concentration.
• The driving force for diffusion is the concentration gradient.
• Brownian motion is the random movement of particles in a fluid.

Brownian Motion

• Discovered by Robert Brown, it's the erratic movement of small particles suspended in a fluid, caused by the continuous bombardment of these particles by the surrounding molecules.

Diffusion in Various States of Matter

• Diffusion occurs in liquids, semi-solids, and solids.
• Examples of diffusion are included in the notes for each state of matter.

Fick's First Law

• Fick's first law describes the rate of diffusion, which is proportional to the concentration gradient, the area across which diffusion occurs, and inversely proportional to the distance between two points in space.

Cooper and Woodman Equation

• Cooper and Woodman described an equation that relates the distance of diffusion in a gel to the time of diffusion through calculation.

Diffusion through a Membrane or Plate

• The rate of diffusion through a membrane or plate is affected by variables.

Other Related Equations

• Equations related to diffusion include Einstein's equation relating diffusion coefficient, time, and temperature.
• Stokes-Einstein equation relates diffusion coefficient, temperature, frictional coefficient, viscosity, and molecular radius.
• Sutherland-Einstein equation links the constant, temperature, Avogadro's number, frictional coefficient, and viscosity.

Polymer Branching

• Polymer branching influences properties such as pore size, frictional coefficient, and solute interactions, affecting diffusion rates.

Electrokinetic Interaction

• Electrokinetic interaction is an interaction between charged particles in a medium, like agar or gelatin, that influences their diffusion rates related to the pH of the solution.

Different types of polymers regarding to their effect on the ionization and solubility.

Concept Check - True or False

• The diffusion process in liquids is described by Fick's First Law.
• The diffusion process is faster in higher temperatures.
• The diffusion process does not depend on the pressure applied.
• The diffusion process depends on the size of the diffusing molecule.

Review Questions

• Review questions are included to test understanding of the material and concepts learned in this physical pharmacy course.

Chromatography

• Chromatography is a technique used to separate and analyze a mixture of gases, liquids, or dissolved substances.
• It involves using two immiscible phases, a mobile phase that transports the mixture, and a stationary phase.
• The components of the mixture separate based on their affinity for the mobile and stationary phases.
• Different types of chromatography include thin-layer chromatography and high-performance liquid chromatography.
• Key concepts in chromatography are the stationary phase, the mobile phase, the sample mixture, and the separation of components due to their differences in affinity for the two phases.

Review Questions

• Review questions are provided on various topics of the physical pharmacy course.

High-Performance Liquid Chromatography (HPLC)

• HPLC is a technique used to separate and analyze a sample mixture.
• HPLC uses a liquid mobile phase to transport the sample mixture through a stationary phase and a detector to monitor components that elute from the column and quantify them.

Dialysis

• Dialysis is a process that separates smaller molecules from larger molecules or dissolved substances from colloidal particles, typically using semi-permeable membranes.

Hemodialysis

• Hemodialysis is a process used to treat renal failure, where blood is purified using a dialysis machine.

Properties of Solutions and Phase Diagrams

• A phase diagram shows the conditions (temperature/pressure) under which different phases of a substance (or a solution) are in equilibrium.

Lyophilization

• Lyophilization (freeze-drying), is a method for drying materials that are sensitive to high temperatures, while maintaining the material’s structure and composition.

Colligative Properties

• Colligative properties depend on the concentration of solute particles, not their nature. Colligative properties include: boiling point elevation, freezing point depression, lowering of vapor pressure, and osmotic pressure.

Review Questions (Fill in the Blanks & True/False)

• Review questions cover different aspects of physical pharmacy concepts, using both fill-in-the-blank and true/false formats.

Review Questions - Additional Topics

• Review questions on various concepts related to the study of ionizable materials and buffer mixtures.

Buffer Solutions

• Buffer solutions are created by mixing a weak acid or base with its salt to minimize pH changes in a solution.
• Different equations are used to calculate the pH or molar ratio for different solution mixtures.

Complexation

• Complexation describes the formation of a more complex species by the association of multiple chemical entities, such as atoms, ions, molecules, or polymers.

Using Polydentate Ligands

• Complexation with polydentate ligands is a method that enhances drug properties, like solubility, and modifies drug behavior concerning stability and metabolism or drug action.
• These ligands are commonly used to improve drug properties or for specific effects.

Review Questions - Various Topics

• The provided summary includes several review questions to check understanding of different concepts.