Gases in Atmosphere

Question 1

What are the approximate percentages for the most abundant gases in atmosphere

Answer 1

Nitrogen: 78.1%
Oxygen = 21.0%
Argon = 0.9%
Carbon Dioxide = 0.04%

Question 2

Experiment to determine the percentage by volume of oxygen in air

Answer 2

Copper Oxidation
100cm^3 air
passes over hot copper to oxidise
Copper is in excess so all O2 used up
Percentage volume of air change

Question 3

What is the test for Oxygen

Answer 3

Glowing splint –> relights

Question 4

What does oxidation mean

Answer 4

Oxidation is the loss of electrons (or gain of oxygen)

Question 5

Describe combustion of Mg, H and S

Answer 5

Magnesium: Bright white flame
MgO- white ash (s)
Hydrogen: Explosive (squeaky pop)
Water is formed (l)
Sulphur: Blue flame
SO2 (g)

Question 6

Describe the formation of CO2 from thermal decomposition of metals

Answer 6

Thermal decomp. = breaking down by heating
CuCO3 –> CuO + CO2
Copper Carbonate –> Copper oxide + Carbon dioxide
green powder –> black powder

Question 7

Is CO2 a greenhouse Gas

Answer 7

Yes
contribute to climate change