Gases In The Atmosphere Flashcards
% of nitrogen in the air
78%
% of oxygen in the air
21%
% Argon in the air
0.93%
% of carbon dioxide
0.04%
What metal can be used to determine the % of oxygen in the air?
Iron: iron reacts with oxygen in the air to form rust - iron will remove oxygen from the air
Experiment for oxygen in the air
Soak IRON WOOL in AFETIC ACID
Push the wool into a MEASURING CYCLINDER and invert the measuring cylinder into a beaker of water
What is the calculation for the final volume of air?
Start volume - final volume
—————————————
Start volume
X100
Test for % oxygen in the air using phosphorus
Place phosphorus in a tube and attach a glass syringe at either end
Are gases in a reaction reactants or products
Can be both
What do you get when you burn an element in air
Reacts with oxygen to form an oxide
These oxides can have either acidic or basic character
Magnesium
Burns with a BRIGHT WHITE FLAME
White powder formed - MAGNESIUM OXIDE
magnesium oxide is slightly ALKALINE when dissolved in water
2Mg + 02 —> 2MgO
Hydrogen
Burns VERY EASILY in oxygen, can be EXPLOSIVE
PALE BLUE FLAME (almost invisible)
Only product is WATER
Combustion of hydrogen is often used as a TEST for hydrogen gas
‘SQUEAKY POP’
2H + O —> 2H O
2 2 2
Sulfur
Burns in air or oxygen
PALE BLUR FLAME
produces SULFUR DIOXIDE
—> ACIDIC when dissolved in water
S + O —> SO
2 2
Thermal decomposition
When a substance breaks down into simpler substances when heated
By heating a metal carbonate —> carbon dioxide + metal oxide
Copper (II) carbonate
GREEN POWDER
Easily decompose to form CARBON DIOXIDE and COPPER (II) CARBONATE when heated
