GasesInAtmosphere (combustion/thermal decomposition/greenhousegases) Flashcards
What is the percentage of gases in the atmosphere in descending order
Nitrogen 78%
Oygen 21%
Argon 0.9%
Carbon dioxide 0.04%
What are three metals that can be used to test for the presence of oxygen in the air
Copper
Phosphorous
Iron
In the experiment using copper to test for the presence of oxygen, why are both syringes pushed back and forth
So that the air in the system keeps passing over the copper
In the experiment using copper to test for the presence of oxygen, why is the bunsen burner passed along the tube
To ensure that fresh copper is heated
What is the main gas left in the air in the syringes once the experiment to test for the presence of oxygen using copper has finished?
Nitrogen
(because oxygen is used up)
Why is it important to use excess metal in experiments testing for the presence of oxygen in the air
To ensure that all of the oxygen is removed
John doesnt use excess copper in his experiment to test for the presence of air with oxygen.
Explain why this may be a problem
All of the oxygen may not have reacted, so the percentage of oxygen calculted will be inaccurate and too low
Why may it be better to test for the presence of oxygen using copper experiment rather than iron experiment
Because iron experiment is time consuming (takes about a week)
How would you measure the total intial volume of oxygen in the experiment using iron to test for the presence of air
Add the volume of oxygen in the gas syringe, the connecting tube and the conical flask
Give two reasons why the volume of oxygen collected at the end may not be 21%
1- Because the metal may not have been excess so all the oxygen wouldnt have been able to react
2- The experiment wasnt left long enough so there wasnt enough time for all the oxygen to react
Why is phosphorous a good non-metal to use when testing the presence or oxygen in the air
Because it is very reactive and reacts fast
When phosphorous oxide is produced, what does it look like in the bell jar
A white smoke
How is the phosphorous heated in the bell jar when the bung is removed
With a hot wire
What colour is magnesium oxide
White powder
What colour is the flame for burning sulfur
Blue
What colour is sulfur
Yellow powder
What colour flame does hydrogen oxide burn in
Pale blue
What colour flame does magnesium oxide burn in
Bright white flame
What colour is magnesium
Silver ribbon