Air Flashcards
What is air composed of(%)?
78% nitrogen
21% oxygen
1% carbon dioxide, water vapour, argon
Explain the method of the experiment to show that oxygen makes up a fifth of the air
Pack steel wool into the bottom of a graduated cylinder and place upside down into a water trough.
Leave for a week
Measure the height the water has risen up the cylinder
Explain the result and conclusion of the experiment to show that oxygen makes up a fifth or the air
Water rises 1/5 of the way up the cylinder to replace oxygen used to rust steel wool.
Conclusion:1/5 of air is made up of oxygen
Explain the method,result and conclusion of the experiment to show that carbon dioxide in air
Set up respiration apparatus
Inhale through tubing until limewater turns milky because air is being pulled through it
Result: Limewater goes milky
Conclusion: carbon dioxide is present in air
Give the properties of oxygen
Colourless odourless gas Relights a glowing splint Supports combustion A neutral gas Magnesium burns brightly in oxygen
Explain the method, result and conclusion of the experiment to show there is water vapour present in the air
Set up apparatus and fill test tube with ice and cold water
Hold test tube over copper sulphate and allow condensation droplets to fall onto the copper sulphate
Result:copper sulphate goes blue(proof that droplets are water)
Conclusion: there is water vapour in the air
Give the properties of carbon dioxide
Colourless odourless gas Does not support combustion It will extinguish a flame It is more dense than air It is slightly acidic, turns blue litmus paper red Turns limewater milky
Give the word equation to prepare a sample of oxygen
Manganese dioxide
Hydrogen peroxide ———————-» water and oxygen
Give the chemical equation to prepare a sample of oxygen gas
MnO2
2H2O2———–» 2H2O+O2
Name three uses of oxygen
Breathing
Welding
Burning
Explain a catalyst
A chemical that speeds up or slows down a chemical reaction without itself being used up or being changed
Explain the what happens and the method in the experiment to prepare a sample of oxygen gas and examine its properties
Oxygen is prepared by hydrogen peroxide being broken down into water and oxygen. Manganese dioxide is the catalyst
Tap of funnel is opened and hydrogen peroxide is dropped into manganese dioxude. Oxygen collects in gas jar and can be tested
Explain the atmosphere
The atmosphere is the layer of gases around the Earth
Explain the method of the experiment using Copper turnings how to measure the percentage of oxygen in air
Set up the syringe apparatus
Make sure one syringe contains 100 cm3 of air and the other syringe is completely closed/down.
Heat the copper turning with a bunsen burner and slowly pass the 100 cm3 of air from one syringe to the other.
Pass the air from syringe to syringe several times or until the volume does not change.
Let the apparatus cool down and read the final volume of air left.
Explain the result of the experiment using Copper turnings how to measure the percentage of oxygen in air
The volume of air in the syringe will go down to approximately 80 cm3 and the copper turnings turn grey-black in colour. This is because copper reacts with the oxygen present, forming copper oxide.
