Chapter 28- Water Flashcards Preview

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Flashcards in Chapter 28- Water Deck (13)
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1

Electrolysis

The splitting of water
-add a little but of dilute sulfuric acid to water
- Hoffman apparatus (two upside down test tubes w/ wires in them, connected to battery)
-gas builds up, one twice more than the other (H) (the other is O)

2

Expansion of water

Substances-expand when heated
-contract when cooked

Water -expands over 4°, shrinks to 4°
-if cooled further, it expands again!

3

Meniscus

•water clings to glass
•when in a narrow container, the sides cling
•curved lens surface at the top of the water is called the meniscus

4

Desalation

To remove salt from seawater

House w glass roof
Pool of water w black bottom
Water evaporates
Condenses on glass, drips to the side and falls into pits at the side of the pool

5

Properties of water

-freezing point 4°
-boiling point 100°
- excellent solvent
-colourless,odourless liquid

6

Experiment to prove:
The presence of dissolved substances in a water source

Filter insoluble solids using paper and funnel

Pour filtered water onto clock glass(evaporation dish)

Put on beaker full of boiling water on hot plate ->
Water will evaporate->
Leaves residue

7

Rhyme for remembering the processes carried out to filter water

Silly Sean follows Chelsea football

8

What is screening

Water is passed through a wire mesh

Removes leaves/ litter etc.

9

What is settling

Aluminium sulfate added to water
Smal, insoluble particles come together +settle at the bottom of tanks

10

Filtration

Water is passed through beds of sand
Silvers small insoluble particles
Clear water but still contains bacteria

11

Chlorination

Kills bacteria in water
Carefully monitored

12

Fluoridation

Prevents tooth decay 🙃

13

Tests for water

Cobalt Chloride (blue-> pink)
Anyhydrous copper sulfate (white -> blue)