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Flashcards in Chapter 27- The Atmosphere Deck (11)
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Experiment to prove:
Oxygen occupies 21% of air (iron)

Upside down graduated cylinder w/ steel wool at the very top
Placed in trough
Iron will react with oxygen sucking water up to 21sm mark on the cyclinder


Experiment to prove:
Oxygen is 21% of the atmosphere

One syringe has 100mm^3 of air, one closed

Heat and pass air

Copper turns grey black (now copper oxide)

Air=80cm^3 as oxygen has reacted with the heated copper


Experiment to:
Prepare oxygen

•Put hydrogen peroxide in syringe
•Through stopper on beaker with manganese dioxide in it
•They react when released
•Oxygen goes back out stopper, down tube, under beehive shelf and up into a test tube (previously filled with water)


Tests for oxygen

1. Colour, smell, pH ----------> colourless, odourless, neutral
2. Glowing split in jar --------> Ré-lights
3. Burn magnesium ribbon---> burns white light


Experiment to:
Prepare carbon dioxide

•Hydrochloric acid dropped from syringe, through stopper
• reacts with calcium carbonate
•Co2 goes up, down tube, under beehive shelf, up test tube


Word equation for the preparation of oxygen

Hydrogen peroxide +manganese dioxide --->Oxygen +water

2H2O2+MnO2--> O2 + 2H2O


Word equation for the preparation of Co2

HCL + CaCo3 = CO2 + H2O+ CaCl2

Hydrochloric acid + calcium carbonate
Carbon dioxide + Water + Calcium Chloride


3. Tests to prove Co2

1. Colour, smell, pH ----------> colourless, odourless, acidic
2. Add limewater ------------> colour change
3. Pour on candle -----------> extinguishes


Equation for limewater and Co2

Calcium hydroxide+Carbon Dioxide->
Calcium Carbonate+Water

Ca(OH)2 + Co2 -> CaCO3 + H2O


Uses for Co2

-fire extinguishers
-fizzy drinks
-stage effects



78% of air
Condenses at -200°c