Atmosphere & Oxygen Flashcards
Gases in the early atmosphere
Water vapour, carbon dioxide, nitrogen, other gases
What the atmosphere like 4.5 Billion years ago?
Mostly water vapour because of lots of volcanic activity (very hot)
What the atmosphere like 4 billion years ago?
Mostly carbon dioxide with water cooling down forming the oceans
What the atmosphere like 2.5 Billion years ago?
Increased in oxygen and decreased in carbon dioxide because of the evolution of bacteria and algae
What the atmosphere like 200 million years ago?
The atmosphere was mostly nitrogen and oxygen and
The atmosphere had stabilised because of respiration in animals and plants
What is the atmosphere like currently?
The atmosphere has stayed the same and there has not been any change
What is the composition of the current gases in the air?
Nitrogen - 78%
Oxygen - 21%
Argon - 0.9%
Carbon Dioxide - 0.04%
What is fractional distillation?
The method used to separate air
Steps of fractional distillation.
- Cool air down to -200°C
(Carbon dioxide is solid at -200°C, so it can be easily removed) - Pass the liquid air into a fractionating column - cooler at the top and warmer at the bottom
-190°C at the top and -185°C at the bottom
(Nitrogen has a boiling point of -196°C so it turns from liquid to gas rises up the column and is collected at the top)
(Oxygen has the boiling point of -183°C, so it stays as the liquid at the bottom of the column and can be collected there)
What are the 3 components of the fire triangle?
Oxygen, heat and fuel
How do you put out a fire?
By removing one, or more of the components of the fire triangle to reach the fire
What is combustion?
Burning in oxygen (releases heat energy)
What is oxidisation?
Reaction with oxygen, where an element gains some oxygen
What is incomplete combustion?
Burning in a limited supply of oxygen
What is the test for carbon dioxide?
Limewater turns cloudy
What is the test for water?
Blue cobalt chloride paper turnspink
What is the symbol equation for complete combustion?
Chemical + O2 —> CO2 + H2O
What is the symbol equation for incomplete combustion?
Element + O2 —> CO + H2O
Products of complete combustion.
CO2 + H20
Products of incomplete combustion.
CO + H2O
What does the reaction with air and copper tell you about the amount of oxygen?
As the syringes pass the air over the copper in the heated tube it draws in the oxygen and reduces the amount of air in the tube by 21% roughly, as in the air there is 21% of oxygen
What type of reaction does copper and oxygen have?
Oxidisation reaction
What does the reaction with air and phosphorus tell you about the amount of oxygen?
As the phosphorus sits in the evaporating basin the air in the bell jar draws in the oxygen and reduces the amount of air in the by 21% roughly, and the water rises by about 21% as in the air there is 21% of oxygen
Properties of non-metal oxides.
Acidic + gases
Properties of metal oxides.
Alkaline + solids
What type of reaction does phosphorus and oxygen have?
Oxidation reaction
Properties and uses of nitrogen
Property - important plant nutrient
Use - to make fertilisers
Properties and uses of oxygen
Property - reactant in respiration
Use - life support and other medical uses
Properties and uses of carbon dioxide
Property - starves fire of oxygen
Use - fire extinguishers
Properties and uses of helium
Property - less dense than air
Use - to fill balloons
Properties and uses of neon
Property - glows
Use - advertising signs
Properties and uses of argon
Property - inert (unreactive)
Use - lightbulbs
Properties and uses of krypton
Property - energy saving
Use - lighting
