Review the key concepts, formulae, and examples before starting your quiz.
🔑Concepts
Water is often called the 'Universal Solvent' because it can dissolve many substances. The chemical formula for water is .
A Solute is the substance that dissolves in a liquid (e.g., sugar or salt).
A Solvent is the liquid in which the solute dissolves (e.g., water).
A Solution is the uniform mixture formed when a solute completely dissolves in a solvent.
Soluble substances are those that dissolve completely in water, such as salt or sugar.
Insoluble substances are those that do not dissolve in water, such as sand, stones, or oil.
The process of dissolving can be sped up by stirring, heating the solvent, or breaking the solute into smaller pieces.
📐Formulae
💡Examples
Problem 1:
Riya adds 5 grams of salt to a glass of and stirs it until the salt disappears. Identify the solute, the solvent, and the resulting mixture.
Solution:
Solute: Salt; Solvent: Water (); Solution: Saltwater.
Explanation:
In this process, the salt is the substance being dissolved (solute), the water is the liquid doing the dissolving (solvent), and the final clear mixture is the solution.
Problem 2:
If you mix a spoon of sand into a beaker of , why does it not form a solution?
Solution:
Because sand is an insoluble substance.
Explanation:
A solution is only formed when a solute dissolves completely. Since sand particles remain visible and settle at the bottom of the , it is an insoluble mixture rather than a solution.
Problem 3:
Which will dissolve faster in : a whole sugar cube or a spoonful of powdered sugar?
Solution:
Powdered sugar.
Explanation:
Powdered sugar has smaller particles, which allows the molecules to surround and dissolve them much more quickly than a solid cube.