All questions of Properties of Materials for Year 4 Exam

Evaporation is used to separate sugar from a sugar-water solution. By heating the solution, the water evaporates, leaving behind the sugar crystals. This method works because sugar dissolves in water but does not evaporate with it.

Gases are highly compressible because they have large intermolecular spaces between particles, allowing them to be compressed into a smaller volume. This is due to the negligible forces of attraction between gas particles.

Gases exhibit the highest rate of diffusion because their particles are widely spaced and move freely, allowing them to mix rapidly with other gases. This high mobility contrasts with the slow diffusion in solids and liquids.

The Role of a Solute in a Solution
In a solution, a solute plays a crucial role in creating a homogenous mixture with the solvent. Let's explore this concept further.
Definition of a Solute
- A solute is a substance that is dissolved in a solvent.
- Common examples include salt in water or sugar in tea.
Formation of a Mixture
- When a solute is added to a solvent, it disperses evenly throughout the solvent.
- This process creates a solution, where the solute is no longer visible as a separate entity.
Interaction with the Solvent
- The solute interacts with the solvent molecules, breaking into smaller particles.
- This interaction is vital for the solute to dissolve effectively.
Importance of Homogeneity
- A solution is characterized by its uniform composition, meaning every part of the solution has the same properties.
- The solute ensures that the solution is consistent, making it useful for various applications, such as cooking or chemical reactions.
Conclusion
- In summary, the solute's main role is to mix with the solvent to form a solution.
- This mixture allows for the properties of both substances to be utilized in various practical scenarios.
By understanding the role of a solute, we gain insight into the nature of solutions and their importance in everyday life.

Sedimentation and decantation are used to separate sand from water. Sand settles at the bottom of the glass, and the clear water can be poured off, leaving the sand behind. This method is effective for separating insoluble solids from liquids.

Condensation involves a substance changing from a gas to a liquid. For example, water vapor in the air condenses into liquid water when cooled, such as when steam forms droplets on a cold surface.

Tea leaves are an example of an insoluble substance in water. Unlike sugar and salt, which dissolve, tea leaves do not dissolve in water. They remain separate and can be filtered out from the liquid.

During evaporation, the molecules of a substance move further apart as they gain enough energy to escape the liquid state and enter the gas phase. This process involves an increase in kinetic energy and movement of molecules.

The rate of diffusion increases when a substance changes from a solid to a liquid. In liquids, particles are less tightly packed and can move more freely compared to solids, allowing for faster diffusion.