Reactions

Question 1

Percentage of gases in the air

Answer 1

78% nitrogen
21% oxygen
0.9% argon
0.04% carbon dioxide
Others 0.06%

Question 2

Uses of oxygen

Answer 2

Breathing apparatus
Welding
Rocket fuel

Question 3

What is combustion

Answer 3

A chemical process when a substance reacts rapidly with oxygen and gives off heat

Question 4

Word equation for oxygen

Answer 4

Hydrogen peroxide—> water + oxygen

Question 5

Preparation for oxygen

Answer 5

Chemicals required - hydrogen peroxide and manganese dioxide catalyst

Diagram - side arm test tube with bung with hydrogen peroxide and manganese dioxide going into trough of water with upside down test tube collecting oxygen gas

Question 6

Test for oxygen

Answer 6

Relights glowing splint

Question 7

Uses for hydrogen

Answer 7

Generates electricity

Question 8

Word equation for hydrogen

Answer 8

Magnesium + hydrochloric acid—-> magnesium chloride + hydrogen

Question 9

Preparation for hydrogen

Answer 9

Chemicals required- magnesium and hydrochloric acid

Diagram - side arm test tube with hydrochloric acid and magnesium with upward delivery tube and test tube upside down collecting hydrogen

Question 10

Test for hydrogen

Answer 10

A lit splint will burn with a squeaky pop

Question 11

Uses of carbon dioxide

Answer 11

Dry ice
Fire extinguisher
Green house effect

Question 12

Word equation for carbon dioxide

Answer 12

Calcium carbonate + hydrochloric acid —> calcium chloride + water + co2

Question 13

Preparation for co2

Answer 13

Chemicals needed- marble chips, hydrochloric acid and limewater

Diagram- side arm test tube with hydrochloric acid and marble chips and test tube with limewater

Question 14

Test for carbon dioxide

Answer 14

Turns limewater milky

Question 15

What does Exothermic mean

Answer 15

A reaction that gives out heat

Question 16

What does endothermic mean

Answer 16

A reaction that take in heat and cool down

Question 17

Test for water

Answer 17

Anhydrous copper sulfate goes from white to blue