Chemical Equilibria and Acid-Base Chemistry (Undergraduate Foundation)

This course provides a complete guide to chemical equilibria, the state where the rates of forward and reverse reactions are equal. It covers the law of mass action, the definition and calculation of the equilibrium constant, and the factors that can cause a shift in the equilibrium position. The course then applies these principles to the study of aqueous equilibria, including the properties of acids, bases, and salts, and the calculation of pH. The principles of equilibrium govern the outcomes of all reversible reactions, from industrial synthesis to biological processes. A command of this topic is essential for chemists and chemical engineers to maximise the yield of a desired product, for environmental scientists to understand natural water systems, and for biochemists to analyse metabolic pathways. By the end of this course, you will be able to write the expression for the equilibrium constant for any reversible reaction, use Le Chatelier's principle to predict how a system at equilibrium will respond to changes in concentration, pressure, or temperature, and perform calculations involving the pH of acidic and basic solutions. This course is for students who have a solid foundation in stoichiometry. It is a mandatory course for all students of chemistry and chemical engineering and is a direct prerequisite for the study of analytical chemistry, biochemistry, and environmental science.

Payment required for enrolment

Enrolment valid for 12 months

This course is also part of the following learning track. You may join the track to gain comprehensive knowledge across related courses.

[NUC Core] CHM 101: General Chemistry I

This learning track delivers the complete NUC CCMAS curriculum for General Chemistry I. It is a comprehensive programme designed to build a robust, university-level foundation in modern chemistry. The track systematically covers all essential topics, from atomic theory, chemical bonding, and the states of matter, to the quantitative principles of stoichiometry, equilibrium, thermodynamics, and kinetics. This programme is for first-year undergraduates in science, technology, engineering, and mathematics (STEM) faculties who are required to take CHM 101. It is also essential for any student or professional globally who needs a rigorous and complete foundation in first-year university chemistry for further study or career development. This track delivers a full skill set in chemical theory and quantitative problem-solving. Graduates will be able to determine molecular structures, calculate reaction quantities, analyse the energetics and rates of reactions, and solve complex equilibrium problems. This programme provides the non-negotiable prerequisite knowledge for all subsequent chemistry courses and for any degree in the physical sciences, engineering, or medicine.

Course Chapters

1. Introduction

This chapter provides the roadmap for the course. It introduces the concept of a dynamic, reversible chemical reaction and outlines the progression from the principles of equilibrium to their application in acid-base chemistry. Key learning objectives include: understanding the overall course structure and appreciating the importance of equilibrium in controlling the outcomes of chemical reactions.

Chapter lessons

1-1. Welcome

This lesson provides a brief overview of the course, outlining the key topics of the equilibrium constant, Le Chatelier's principle, and acid-base chemistry.

2. Chemical Equilibrium

This chapter covers the foundational principles of chemical equilibrium. It defines the dynamic state of equilibrium and introduces the equilibrium constant as the quantitative measure of a reaction's position. Key learning objectives include: defining dynamic equilibrium; writing the expression for the equilibrium constant (Kc); and understanding the law of mass action.

Chapter lessons

2-1. Dynamic equilibrium

This lesson defines a dynamic equilibrium as the state where the rates of the forward and reverse reactions are equal, resulting in no net change in concentrations.

2-2. The equilibrium constant

This lesson introduces the law of mass action and the equilibrium constant (Kc), which relates the concentrations of products and reactants at equilibrium.

3. Le Chatelier's Principle

This chapter is dedicated to Le Chatelier's principle, which explains how a system at equilibrium responds to external stresses. The focus is on predicting the direction of the resulting shift in equilibrium. Key learning objectives include: stating Le Chatelier's principle; and predicting how changes in concentration, pressure, and temperature will affect an equilibrium mixture.

Chapter lessons

3-1. The principle defined

This lesson formally states Le Chatelier's principle: if a change of condition is applied to a system in equilibrium, the system will shift in a direction that relieves the stress.

3-2. Effect of concentration

This lesson explains how an equilibrium system responds to a change in the concentration of a reactant or product.

3-3. Effect of pressure

This lesson covers how changes in pressure affect gaseous equilibria by favouring the side with fewer moles of gas.

3-4. Effect of temperature

This lesson explains how an equilibrium system responds to a change in temperature, favouring the endothermic or exothermic direction.

4. Acids, Bases, and Salts

This chapter introduces the fundamental concepts of acid-base chemistry, a major application of equilibrium principles. It covers the definitions, properties, and quantitative measures of acids, bases, and the salts formed from their reactions. Key learning objectives include: defining acids and bases; understanding the pH scale; and identifying the different types of salts and their properties in solution.

Chapter lessons

4-1. Definitions of acids

This lesson covers the common definitions of acids and bases, including the Arrhenius and Brønsted-Lowry theories.

4-2. The pH scale

This lesson introduces the autoionization of water and the resulting pH scale as the standard measure of acidity and alkalinity in aqueous solutions.

4-3. Definition of salts

This lesson formally defines a salt as an ionic compound resulting from the neutralisation reaction of an acid and a base.

4-4. Types of salts

This lesson covers the classification of salts as acidic, basic, or neutral based on the strengths of the parent acid and base from which they are formed.

4-5. Hydrolysis of salts

This lesson explains the process of salt hydrolysis, where the ions of a salt react with water to produce acidic or basic solutions.

5. Conclusion

This concluding chapter summarises the key concepts of the course. It reinforces the understanding of the principles of chemical equilibrium and their direct application to acid-base chemistry. This summary prepares the student for the next course, 'Chemical Thermodynamics', which explores the energy changes that drive reactions towards equilibrium.

Chapter lessons

5-1. Course summary

This lesson consolidates knowledge by reviewing the equilibrium constant, Le Chatelier's principle, and the fundamentals of acid-base-salt chemistry.

5-2. Next steps

This final lesson looks ahead, explaining how an understanding of equilibrium is a direct prerequisite for the study of chemical thermodynamics and reaction spontaneity.