*Topic 2-reactions Part 1

Question 1

What is gases is air a mixture of

Answer 1

Nitrogen
Oxygen 
Carbon dioxide 
Water vapour 
Noble gases

Question 2

Name the % of each gas in the air

Answer 2

Oxygen- 21%
Nitrogen-78%
Argon-0.9%
Carbon dioxide-0.037%

Question 3

Name uses of Oxygen

Answer 3

Welding torches
Rocket fuel
Breathing apparatus in hospitals

Question 4

Name uses of carbon dioxide

Answer 4

Fizzy drinks
Fire extinguisher
Dry ice

Question 5

Name 3 physical properties of oxygen

Answer 5

Colourless odourless gas, not very soluble in water, same density as air

Question 6

Give 2 physical properties of carbon dioxide

Answer 6

Gas

Colourless and odourless

Question 7

Describe preparation of oxygen in the lab using manganese dioxide and hydrogen peroxide

Answer 7

Hydrogen peroxide->water+oxygen
Wear eye protection
Causes serious eye irritation
Harmful by inhaling and if swallowed

Question 8

What does a catalyst do

Answer 8

A chemical that speeds up a reaction without being used up itself

Question 9

What are enzymes

Answer 9

Biological catalysts

Question 10

Describe the outcome of the test for oxygen

Answer 10

Glowing splint will re-light

Question 11

Recall the preparation of hydrogen by reacting a metal with acid

Answer 11

Magnesium+Hydrochloric Acid->magnesium chloride+Hydrogen

Question 12

How do you test for Hydrogen gas

Answer 12

A lit splint will burn with a squeaky pop

Question 13

What mixture of gases is explosive

Answer 13

H2 and O2

Question 14

Explain safety precautions for preparing/using hydrogen

Answer 14

Wear eye protection
It’s flammable
Causes burns

Question 15

Recall the preparation of carbon dioxide from the reaction of marble chips

Answer 15

Calcium carbonate +hydrochloric acid -> calcium chloride +water + carbon dioxide

Bubbles of gas
Calcium carbonate disappears

Question 16

Describe the test for the presence of CO2

Answer 16

Limewater goes from colourless to cloudy OR a lit splint will go out in a test tube of CO2

Question 17

Recall some every day uses of carbon dioxide

Answer 17

Fire extinguishers
Fizzy drinks
Dry ice

Question 18

What are exothermic and endothermic reactions

Answer 18

Exothermic- a reaction that releases heat energy

Endothermic- absorbs heat energy

Question 19

Give examples of an exothermic reaction

Answer 19

Combustion

Question 20

Give an example of an endothermic reaction

Answer 20

Photosynthesis

Question 21

What is oxidation

Answer 21

Addition of oxygen

Question 22

What is reduction in a redox reaction

Answer 22

Removal of oxygen

Question 23

In a REDOX reaction what processes occur in the same reaction

Answer 23

Oxidation

Reduction