Review the key concepts, formulae, and examples before starting your quiz.
🔑Concepts
Water is essential for all living organisms. Its chemical representation is .
Rain is the primary source of water on Earth. It fills up other water bodies like rivers, lakes, and ponds.
Surface Water includes oceans, seas, rivers, lakes, and streams. About of the Earth's surface is covered with water.
Groundwater is water that seeps into the soil and is stored under the ground. We can access it using wells, tube wells, and hand-pumps.
Water exists in three states: Solid (ice), Liquid (water), and Gas (water vapor).
Domestic uses of water include drinking, cooking, bathing, washing clothes, and cleaning utensils.
Agricultural uses involve irrigation to help crops grow, while industrial uses include cooling machinery and manufacturing goods.
The temperature at which water turns to ice is (Freezing Point) and the temperature at which it boils is (Boiling Point).
📐Formulae
💡Examples
Problem 1:
Identify the primary source of water and state the chemical formula of water.
Solution:
The primary source of water is Rain. The chemical formula is .
Explanation:
Rainwater collects in various water bodies and also seeps into the ground to become groundwater. represents two atoms of Hydrogen and one atom of Oxygen.
Problem 2:
At what temperature does water change from a liquid to a gas at sea level?
Solution:
Explanation:
When water is heated to its boiling point of , it undergoes a phase change from liquid to water vapor (gas).
Problem 3:
If the Earth's surface is water, why must we still conserve it?
Solution:
Most of that water is salty () and found in oceans.
Explanation:
Only a very small percentage (approx ) is freshwater, and even less is available for drinking. Thus, conservation is vital.