Complete Study Guide
Includes dams, lakes, streams, rivers, seas, and oceans
Rainwater collected from rooftops during rainy season
The hydrological cycle describes continuous water circulation between earth's surface and atmosphere:
Sun's heat causes water to evaporate from oceans, seas, and lakes
Plants release water vapor into atmosphere
Water vapor cools and condenses to form clouds
Droplets fall as rain, flowing into streams and rivers
Engine cooling, distillation
Dissolves many substances
Aqueous reactions
Electricity generation
Swimming pools
Boats and ships
Caused by dissolved calcium or magnesium hydrogen carbonates. Removable by boiling.
Caused by calcium or magnesium sulphates. Treated by distillation or chemical methods.
Heating causes hydrogen carbonates to decompose into insoluble carbonates
Calcium/sodium hydroxide precipitates calcium and magnesium ions
Water is distilled to separate from dissolved substances (costly for large-scale)
Precipitates calcium and magnesium ions as carbonates
Resin exchanges calcium/magnesium ions for sodium ions
Introduction of harmful substances into water due to human activities, including toxic metals, plastics, pesticides, and fertilizers.
Human waste and sewage released into lakes and rivers
Effluents from breweries, tanneries, textiles, paper industries
Pesticides, herbicides, fertilizers that runoff after rains