Review the key concepts, formulae, and examples before starting your quiz.
🔑Concepts
A Solute is the solid substance that dissolves in a liquid, such as sugar or salt ().
A Solvent is the liquid in which the solute dissolves. Water () is known as the 'universal solvent'.
A Solution is the transparent mixture formed when a solute dissolves completely in a solvent.
Soluble substances (like salt) disappear into the liquid to form a clear solution, while Insoluble substances (like sand) do not dissolve and often settle at the bottom.
A Saturated Solution is a mixture where no more solute can be dissolved in the solvent at a given temperature.
The rate of dissolving can be increased by stirring, increasing the temperature of the solvent, or using smaller particles of the solute.
In a solution, the total mass is conserved: .
📐Formulae
💡Examples
Problem 1:
If you add of salt () to of water () and stir until it all disappears, what is the final mass of the solution?
Solution:
Explanation:
According to the principle of conservation of mass, the mass of the solution is the sum of the solute and the solvent: .
Problem 2:
Why does sugar dissolve faster in a cup of hot tea than in a glass of iced water?
Solution:
Higher temperature increases the speed of dissolving.
Explanation:
In hot liquids, the water molecules () move faster and have more energy, which helps break down the solute particles more quickly compared to cold liquids.
Problem 3:
Identify which of the following are insoluble in water: Sugar, Sand, Salt, Chalk powder.
Solution:
Sand and Chalk powder.
Explanation:
Sand and chalk are insoluble because their particles do not break down and spread out between the molecules; they remain visible and eventually settle at the bottom of the container.