Gases 🧪

Question 1

CO2 lab prep

Answer 1

CaCO3 + 2HCl —> CaCl2 + H2O + CO2
Observations:
Bubbles
Exothermic

Question 2

Industrial prep

Answer 2

Thermal decomposition of CaCO3 at +1000 degrees
CaCO3 —> CaO + CO2

Question 3

Properties of CO2

Answer 3

Colour less
Odourless
Denser than air
Slightly soluble
Doesn’t support combustion

Question 4

Major uses of CO2

Answer 4

Fire extinguisher
Fizzy drinks
Dry ice

Question 5

test and result of CO2

Answer 5

Pass the gas through lime water Ca(OH)2 (aq)
Colour less—> milky white

Ca(OH)2 + CO2 —> CaCO3 + H2O

Question 6

Lab prep of H2

Answer 6

Mg + 2HCl —> MgCl2 +H2
Observations:
Bubbles of gas
Exothermic

Question 7

Industrial prep of H2

Answer 7

Electrolysis of sea water
2NaCl + 2H2O —> 2NaOH + Cl2 + H2

CH4 + 2H2O —> CO2 + 4H2
On heating 800 degrees and Ni as catalyst

Question 8

Properties of H2

Answer 8

Colourless
Odourless
Less dense than air
Insoluble in H2O
Explosive gas

Question 9

Uses of H2

Answer 9

Manufacturing margarine
Manufacturing NH3
Rocket Fuel

Question 10

Lab prep of O2

Answer 10

2H2O2 —> 2H2O + O2

MnO2 as catalyst

Question 11

Industrial prep of O2

Answer 11

Fractional distillation of liquified air

Question 12

Properties of O2

Answer 12

Odourless
Colourless
Denser than air
Supports combustion
Slightly soluble in H2O

Question 13

Test and result for O2

Answer 13

Glowing splint relights

Question 14

Uses of O2

Answer 14

Artificial breathing
Oxy-acetylene flame to cut and weld metals
Steel manufacturing

Question 15

Lab prep of SO2

Answer 15

NaSO3 + 2HCl —> 2NaCl + H2O + SO2

Question 16

Lab prep of SO2

Answer 16

S + O2–> SO2

Question 17

Properties of SO2

Answer 17

Colourless
Rotten egg smell
Highly soluble in H2O
Acidic

Question 18

Test and result of SO2

Answer 18

Acidified KMnO4 (aq)
Purple —> colourless

Acidified K2Cr2O7 (aq)
Orange—> green

Question 19

Uses of SO2

Answer 19

Paper industry (bleaching)
Food industry (antioxidant) prevents the growth of bacteria
Making H2SO4

Question 20

Lab prep of NH3

Answer 20

NH4NO3 + NaOH —> NaNo3 + H2O + NH3

Question 21

Industrial prep of NH3

Answer 21

N2 + 3H2–> 2NH3

Question 22

Properties of NH3

Answer 22

Colourless
Pungent smell
Alkaline gas
Highly soluble in H2O
Less dense than air

Question 23

Physical test and result for NH3

Answer 23

Damp red litmus paper turns blue

Question 24

Chemical test and result NH3

Answer 24

Dip a glass rod into HCl dense white fumes form when introduced

Question 25

Uses of NH3

Answer 25

Fertilizers
Coolants

Question 26

Lab prep of Cl2

Answer 26

MnO2 + 4HCl —> MnCl2 + 2H2O + Cl2

Question 27

Industrial prep Cl2

Answer 27

Electrolysis of brine
2NaCl + 2H2O —> 2NaOH + H2 + Cl2

Question 28

Test and result for Cl2

Answer 28

Blue to red litmus paper then white (bleaching property)

Question 29

Properties of Cl2

Answer 29

Bleaching property
Greenish yellow gas
Denser than air
Acidic
Choking smell
Highly soluble in H2O

Question 30

Uses of Cl2

Answer 30

Drinking water And pools to kill bacteria
To make PVC poly vinyl chloride