C4: Air and Water Flashcards Preview

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Flashcards in C4: Air and Water Deck (24):
1

% of Nitrogen in the air

78%

2

% of Oxygen in the air

21%

3

% of Argon in the air

0.9%

4

% of Carbon Dioxide in the air

0.04%

5

Nitrogen Boiling Point

-196 C

6

Argon Boiling Point

-186 C

7

Oxygen Boiling Point

-183 C

8

How are the gases in the air separated in industry?

Fractional Distillation of Liquid Air

9

Fractional Distillation of the Air Process

1. Compress the air to 150 times atmospheric pressure. This warms up the air, so it is then passes over cold water pipes)
2. Pressure is released, and air is allowed to expand rapidly. Causes temp to drop enough that the gases -> liquids. CO2 and H2O are removed easily as they are solid at this temperature.
3. Temp is slowly increased and the gases boil off one by one. Nitrogen - Argon - Oxygen

10

O
I
L
R
I
G

Oxidisation is loss (of electrons)
Reduction is gain (of electrons)

11

Bases

The oxide, hydroxide or carbonate of a metal that will react with an acid, forming a salt as one of the products.
Bases dissolved in water are alkalis.

12

Amphoteric Metals

An oxide that displays both acidic and basic properties.

13

Test for oxygen gases.

A glowing splint will relight in oxygen.

14

Metal oxides are...

Basic

15

Non-Metal oxides are...

Acidic

16

3 elements of a water filter and their purposes.

> Carbon- Reduces chlorine in water
> Ion-exchange resin- removes calcium, magnesium, lead, copper and aluminium.
> Silve- Discourages the growth of bacteria in the filter.

17

Desalination

The removal of salts from water to make it safe to drink.

18

Positives of Fluoridation of Water.

> Reduces cavities.
> Protects those with bad dental hygiene.
> Protects from bacteria that causes heart disease.

19

Negatives of Fluoridation of Water.

> Fluorosis- Weakens bones.
> Benefit for teeth is not significant.
> Ethically wrong- no consent from people.
> Can cause learning difficulties and Alzheimers
> Can't control intake.

20

Which metal rusts?

Iron

21

What is needed for iron to rust?

Oxygen and Water.

22

What prevents rusting?

> Paint
> Oil/ Grease
> Plastic
> Less reactive metal
> More reactive metal

23

Galvanised

Iron or Steel objects that have been protected from rusting by a thin layer of zinc metal at their surface.

24

Sacrificial Protection

An effective way to prevent rusting whereby a metal more reactive than iron (e.g zinc or magnesium) is attached to or coated on an object.