Oxygen

Question 1

What is the word equation for preparing oxygen in a lab?

Answer 1

Hydrogen Peroxide —> Water + Oxygen

Question 2

What is the chemical equation for preparing oxygen in a lab?

Answer 2

MnO2

2H2O2 —> 2H2O + O2

Question 3

What is a catalyst?

Answer 3

A catalyst is a substance that changes the speed of a chemical reaction but is not used up in the reaction itself e.g. Manganese Peroxide

Question 4

What are four physical properties of oxygen?

Answer 4

1. Colourless, Odourless, Tasteless gas
2. Rekindles a glowing splint
3. Slightly soluble in water
4. Slightly heavier then air

Question 5

What are three chemical properties of oxygen?

Answer 5

1. Supports combustion - Substances burn vigorously in the presence of oxygen
2. Reacts with most elements to form oxides
3. No effect on litmus

Question 6

What happens when carbon and magnesium burn in oxygen?

Answer 6

CARBON: Glows brightly
MAGNESIUM: Burns vigorously - bright light given off

Question 7

What compound is formed when carbon and magnesium burn in oxygen?

Answer 7

CARBON: Carbon dioxide (CO2)
MAGNESIUM: Magnesium oxide (MgO)

Question 8

What are the uses of oxygen?

Answer 8

1. Breathing: Oxygen stored in cylinders is used to support breathing e.g. Hospitals, Revive Drowned People, Divers.
2. Burning & Welding: Acetylene burns to 3000*C in oxygen. It can melt metal or join it together.
3. Space Rockets: No air in space, so they carry two tanks - hydrogen and liquid oxygen.

Question 9

What happens when carbon and magnesium dissolve in water?

Answer 9

CARBON: Carbonic acid is formed, blue litmus paper turns red
MAGNESIUM: Magnesium hydroxide is formed, red litmus paper turns blue

Question 10

What percent is oxygen, nitrogen and carbon dioxide in the air?

Answer 10

Oxygen: 78%
Nitrogen: 21%
Carbon Dioxide: 0.03%