Solubility Of Subtances (Nigeria Only)


Welcome to the comprehensive course material on the topic of solubility of substances in Chemistry. Solubility is a fundamental concept that plays a critical role in various chemical processes and reactions. Understanding solubility is essential in predicting how different substances will interact in a solution, which is crucial in fields such as analytical chemistry, environmental science, and material science.

Meaning of Solubility:

Solubility refers to the ability of a substance to dissolve in a solvent to form a homogeneous mixture at a molecular level. It is a quantitative measure that indicates the maximum amount of solute that can be dissolved in a given amount of solvent at a specific temperature and pressure.

Saturated and Unsaturated Solutions:

In the context of solubility, solutions can be classified as saturated or unsaturated. A saturated solution is one in which the solvent has dissolved the maximum amount of solute at a given temperature, resulting in any additional solute remaining undissolved. Conversely, an unsaturated solution has not reached its maximum solute concentration and can dissolve more solute.

Solubility as an Equilibrium System:

A saturated solution can be viewed as an equilibrium system where the rate of dissolution of solute is equal to the rate of precipitation of solute. This dynamic balance is essential in understanding how solubility is influenced by factors such as temperature and pressure.

Expressing Solubility:

Solubility can be expressed in terms of mol dm-3 (molarity) and g dm-3 (mass concentration) of the solution or solvent. These units provide a quantitative measure of the solute concentration in a solution.

Solubility Curves and their Uses:

Solubility curves depict the relationship between solubility and temperature for a specific solute-solvent system. These curves are essential in predicting how solubility changes with variations in temperature, which is crucial for various applications in industries such as pharmaceuticals and chemical manufacturing.

Effect of Temperature on Solubility:

The solubility of a substance is often affected by changes in temperature. In general, the solubility of solid solutes in liquid solvents increases with an increase in temperature, while the solubility of gases in liquids decreases with temperature rise.

Relationship between Solubility and Crystallization:

Crystallization is a process in which a saturated solution is allowed to cool or evaporate, leading to the precipitation of solute particles in the form of crystals. Understanding the relationship between solubility and crystallization is essential for purification processes in chemical synthesis.

Crystallization/Recrystallization as a Method of Purification:

Crystallization and recrystallization are widely used methods for purifying solid compounds based on differences in solubility. By controlling the conditions of crystallization, impurities can be eliminated, leading to the production of high-quality substances.

Knowledge of Soluble and Insoluble Salts:

It is crucial to have a thorough understanding of the solubility properties of various salts containing specific cations and anions. By applying solubility rules, one can predict the formation of insoluble precipitates in double displacement reactions.

Calculations on Solubility:

Calculations related to solubility involve determining the amount of solute that can dissolve in a given amount of solvent at a specific temperature. These calculations are essential for quantitative analysis and experimental design in chemical research.

Generalization about Solubility of Salts:

Generalizing the solubility of salts and applying them to qualitative analysis allows chemists to predict the outcomes of chemical reactions involving various cations and anions. By following solubility rules, one can identify the formation of insoluble compounds in solutions.

This course material aims to provide you with a comprehensive understanding of solubility concepts, practical applications, and analytical techniques related to the solubility of substances in Chemistry. By mastering these topics, you will be well-equipped to tackle complex problems in chemical reactions, separations, and material synthesis.


  1. Utilize solubility curves and understand their applications
  2. Identify the relationship between solubility and crystallization
  3. Analyze the effect of temperature on the solubility of a substance
  4. Demonstrate knowledge of soluble and insoluble salts of specified cations and anions
  5. Understand the meaning of solubility
  6. Apply calculations related to solubility
  7. Express solubility in terms of mol dm-3 and g dm-3 of solution/solvent
  8. Explain solubility rules
  9. Explain how a saturated solution functions as an equilibrium system
  10. Generalize the solubility of salts and apply them to qualitative analysis
  11. Differentiate between saturated and unsaturated solutions

Lesson Note

Solubility is defined as the maximum amount of a substance (solute) that can dissolve in a specific amount of solvent at a given temperature to form a homogeneous solution.

Lesson Evaluation

Congratulations on completing the lesson on Solubility Of Subtances (Nigeria Only). Now that youve explored the key concepts and ideas, its time to put your knowledge to the test. This section offers a variety of practice questions designed to reinforce your understanding and help you gauge your grasp of the material.

You will encounter a mix of question types, including multiple-choice questions, short answer questions, and essay questions. Each question is thoughtfully crafted to assess different aspects of your knowledge and critical thinking skills.

Use this evaluation section as an opportunity to reinforce your understanding of the topic and to identify any areas where you may need additional study. Don't be discouraged by any challenges you encounter; instead, view them as opportunities for growth and improvement.

  1. What causes a solution to be classified as saturated? A. It contains the maximum amount of solute that can dissolve at that temperature B. It contains a small amount of solute C. It contains an excess of solute D. It contains only solvent Answer: A. It contains the maximum amount of solute that can dissolve at that temperature
  2. In which units can solubility be expressed? A. g/L of solvent B. mol/L of solute C. g/L of solution D. mol/L of solvent Answer: C. g/L of solution
  3. What is the effect of increasing temperature on the solubility of most solid solutes in water? A. Solubility increases B. Solubility decreases C. Solubility remains constant D. It depends on the specific solute Answer: A. Solubility increases
  4. Which process involves the formation of pure solid particles from a saturated solution? A. Condensation B. Sublimation C. Crystallization D. Dissolution Answer: C. Crystallization
  5. What type of compounds tend to have higher solubilities in water, ionic or covalent compounds? A. Ionic B. Covalent Answer: A. Ionic

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Past Questions

Wondering what past questions for this topic looks like? Here are a number of questions about Solubility Of Subtances (Nigeria Only) from previous years

Question 1 Report

Which of the following sugars is a product of the condensation of monosaccharides?

Question 1 Report

From the diagram above, find the amount of solute deposited when 200 cm3 of the solution is cooled from 55oC to 40oC

Practice a number of Solubility Of Subtances (Nigeria Only) past questions