Review the key concepts, formulae, and examples before starting your quiz.
🔑Concepts
Water exists in nature in three distinct states: Solid (Ice), Liquid (Water), and Gas (Steam or Water Vapor). All three states are made of the same substance, .
Solid State: Ice is the solid form of water. It has a fixed shape and volume. Water turns into ice when cooled to .
Liquid State: Water is the liquid form. It has a fixed volume but takes the shape of the container it is kept in.
Gaseous State: Steam or water vapor is the gaseous form of water. It is invisible and occupies all the available space in a container.
Change of State - Evaporation: The process of liquid water changing into water vapor on heating is called evaporation.
Change of State - Condensation: The process of water vapor (gas) changing back into liquid water on cooling is called condensation.
Change of State - Freezing: The process of liquid water changing into ice (solid) on cooling is called freezing.
Change of State - Melting: The process of ice (solid) changing into liquid water on heating is called melting.
📐Formulae
💡Examples
Problem 1:
What happens to the water level in a puddle on a hot sunny day?
Solution:
The water level decreases because of Evaporation.
Explanation:
The heat from the Sun turns the liquid water into water vapor ( in gas form), which rises into the air.
Problem 2:
Why do we see tiny droplets of water on the outside of a glass containing ice-cold juice?
Solution:
This is due to the process of Condensation.
Explanation:
The water vapor present in the air touches the cold surface of the glass, cools down, and turns back into liquid droplets.
Problem 3:
Identify the state of water when it is heated to .
Solution:
Gaseous state (Steam).
Explanation:
When water reaches its boiling point of , it rapidly changes from a liquid to a gas called steam.