This document outlines a lesson on investigating the factors affecting the solubility and rate of dissolving of substances. It defines solubility and discusses how the nature of the solute and solvent, as well as temperature, impact solubility. For rate of dissolving, factors like surface area, temperature, and stirring rate are covered. Examples of how these concepts are applied in washing machines and the fizzy drinks industry are provided.

1. Lesson Outline To investigate the factors affecting the solubility of substances To investigate the rate of dissolving of substances Quiz

2. Factors Affecting the Solubility of Substances Solubility = maximum amount of a solute which can dissolve in 100 g of solvent at a fixed temperature For example: 200 g of salt in 100 g of water at 30 °C Definition:

3. Factors affecting the solubility of a solute in a solvent: nature of the solute nature of the solvent temperature of the solution Solubility of solids and liquids when temperature Solubility of gases when temperature

4. Factors Affecting the Rate of Dissolving of Substances Rate of dissolving = time taken for solute to completely dissolve when it is added to a fixed amount of solvent Definition:

5. Faster rate of dissolving 85 °C 15 °C Faster rate of dissolving Factors affecting the rate of dissolving a solute in a given volume of solvent: surface area of the solute temperature of the solution rate of stirring

6. Applications at Home and in the Industry Many substances that we use are in the form of solutes, solvents and solutions. Hence, it is important to know about factors affecting the solubility and rate of dissolving of substances At home : washing machine uses hot water and rotating drum to increase the solubility and rate of dissolving of detergent in water In fizzy drinks industry : Temperature of water, Solubility and rate of dissolving extracts BUT, Temperature of water, Solubility and rate of dissolving of carbon dioxide gas