Grade 11 chemistry - Solutions and their reactions

Formula equation

A chemical equation in which all compounds are represented by their chemical formulas

Total ionic equation

A chemical equation in which all highly soluble ionic compounds are written as dissociated ions

Spectator ions

Ions that are not involved in a chemical reaction

Net ionic equation

A chemical equation that includes only the entities that react during the reaction

Leachate

A liquid contaminated with dissolved or suspended substances picked up as the liquid passed through old mines or dump sites

1. Collection

Travelling screens remove debris and other large particles as the water enters the treatment plant

Hard water

Water that has relatively high concentration of Ca²⁺ and Mg²⁺

Soft water

Water that has a relatively low concentration of Ca²⁺ and Mg²⁺

Filtrate

The clear liquid (solvenr and any dissolved substances) collected after a mixture is filtered to remove any solid components

Flame test

A diagnostic test used to identify a specific element

2. Coagulation, Flocculation, and Sedimentation

Chemical known as coagulants mix with the water,causing the small particles in the wate to clump together. Flocculation, which involves gentle mixing, forms a light, fluffy precipitate called a floc. During sedimentation the floc sinks very slowly, taking suspended particles to the bottom of the tank and clearing the water

3. Filtration

The water flows by gravity through efficient filters made up of layers of sand and anthracite (carbon). This removes the remaining floc, other chemical and physical impurities, and most of the biological impurities (bacteria, etc)

4. Disinfection

A disinfectant such as chlorine kills micro-organisms. Alternative disinfectants include ozone or chlorine dioxide, ammonia, potassium permanganate, and even ultraviolet light

5. Aeration

Air, ozone, oxygen, “activated” charcoal, ammonia, chlorine dioxide, or potassium permanganate may be mixed with the water to further reduce taste and colour problems

6. Softening

Sodium carbonate and calcium hydroxide or a phosphate may be added to reduce water hardness by precipitating the calcium and magnesium ions in the water

7. Fluoridation

Some municipalities add a small quantity of fluoride to drinking water because it makes the enamel layer of teeth more resistant to decay

8. Post-chlorination

A final chlorine disinfection treatment kills any remaining micro-organisms. The pH level in the water is adjusted to be slightly basic because even slightly acidic water will corrode metallic pipes

9. Ammoniation

Ammonia stabilizes the chlorine so that it remains dissolved in the treated water for longer periods of time

Flame colour of H⁺

Colourless

Flame colour of Li⁺

Bright red

Flame colour of Na⁺

Yellow

Flame colour of K⁺

Violet

Flame colour of Ca²⁺

Yellow-red

Flame colour of Sr²⁺

Bright red

Flame colour of Ba²⁺

Yellow-green

Flame colour of Cu²⁺

Green

Flame colour of Pb²⁺

Light blue-grey

Flame colour of Zn²⁺

Whitish green