Reactions Of Metals With Oxygen

Question 1

Metal oxides are usually

Answer 1

Solids

Question 2

Formula for metal oxides

Answer 2

Metal + Oxygen ➡️ Metal Oxide

Question 3

Not all metals…

Answer 3

React with oxygen in the air to form metal oxides: some metals are too unreactive e.g. gold

Question 4

Exothermic reactions release

Answer 4

Light and heat energy

Question 5

When exposed to air:

Answer 5

Many metals rust - air contains moisture and some of the oxygen dissolves in the moisture

Question 6

Rust

Answer 6

• Contains iron oxide
• Orange-brown solid that easily flakes off, leaving the underlying metal exposed to air (this metal then also starts to rust)
• Type of corrosion: that results weakness in the metal and literally “eats” it away

Question 7

What can rust

Answer 7

Iron and alloys (containing iron) can rust

Question 8

Rusting process

Answer 8

Is very slow, over long periods of time can cause very serious problems

Question 9

Methods used to prevent formation of rust involve

Answer 9

The exclusion of air (oxygen)

Question 10

Prevention of rust …

Answer 10

Adds cost to an item, corroded components weaken structures and adds cost for parts to be replaced

Question 11

Ways to prevent rust

Answer 11

• Painting
• Oil/grease
• Galvanising
• Electroplating
• Sacrificial anode

Question 12

Oil/grease involves

Answer 12

Lubricating

Question 13

Galvanising

Answer 13

• Zinc layer quickly reacts with oxygen to become zinc oxide
• This layer protects the zinc underneath it from being further oxidised
• Also protects the iron underneath the zinc from contact with oxygen

Question 14

Electroplating

Answer 14

Chromium is a metal highly resistant to corrosion

Question 15

Non-metals can also

Answer 15

Combust

Question 16

Phosphorous

Answer 16

• Non-metal that burns more easily than others in oxygen
• Relatively pure sample of phosphorous comes into contact with air, will ignite spontaneously & burn with an orange flame

Question 17

Different forms of phosphorous

Answer 17

• White phosphorous
• Red phosphorus

Question 18

Both forms of phosphorous (red and white) are…

Answer 18

Stored under water: so that they don’t/can’t come into contact with the oxygen in the air

Question 19

Application of combustion

Answer 19

• Striking surface of matchbox: mixture of substances e.g. red phosphorous
• Matchs head: dipped in mixture that contains potassium chlorate and sulphur
• When match is striked, friction causes red phosphorous to react vigorously with potassium chlorite in presence of oxygen. Match ignites

Question 20

Acid rain:

Answer 20

• Vehicles, diesel fumes, burning of coal & oil emits nitrogen oxide, sulphur dioxide, carbon dioxide, carbon monoxide and water in atmosphere
• When non-metal oxides dissolve in water, they are acidic, results in “acid rain”
• Can have harmful effects on plants, animals and buildings

Question 21

For combustion

Answer 21

• Fuel
• Oxygen
• Heat