Oxides, oxygen and water Flashcards
What % does nitrogen form in the atmosphere?
78%
What % does oxygen form in the atmosphere?
21%
What % does argon form in the atmosphere?
0.9
What % does carbon dioxide form in the atmosphere?
0.04%
What fraction does nitrogen form in the atmosphere?
approx. 4/5
What fraction does oxygen form in the atmosphere?
approx. 1/5
What % of water vapour can there be in air?
0%-4%
Describe the experiment to measure the % of O2 in the air using iron wool? (4)
1) Place iron wool at the bottom of a test tube and turn in upside down
2) But it into a beaker with water
3) Mark the water level in the test tube with a rubber band
4) Leave for several days
What will happen to the water level in the iron wool experiment?
It will rise, as the oxygen is being used up, therefore the water gets sucked into the test tube
What is the chemical equation for a iron wool experiment?
4Fe + 3O2 → 2Fe2O3
Describe the experiment to measure the % of O2 in the air using gas syringes? (3)
1) Place copper in a central part
2) Connect gas syringes from both sides
3) Make sure it is air tight
Describe how to carry out the experiment with gas syringes (2)
1) The copper is heated using a bunsen burner
2) The air is pushed backwards and forwards across the gas syringes
How much air does the apparatus contain in the gas syringe experiment?
100 cm3
What is going to happen to copper in the gas syringe experiment?
Copper oxide is going to be formed
What is the equation in the gas syringe experiment?
2Cu + O2 → 2CuO
When the reaction is completed in the gas syringe experiment how much gas will be left?
approx. 79cm3
What is the formula of hydrogen peroxide?
H2O2
How to prepare oxygen in a lab?
Made from hydrogen peroxide using manganese oxide as a catalyst
Write an equation of production of oxygen in a lab with state symbols
2H2O2(aq) using manganese (IV) oxide → 2H2O(l) + O2(g)
Why happens to the catalyst? Where is it written in an equation?
It doesn’t react, therefore it is written above the arrow
What is the test for oxygen?
Glowing splint relights in it
Are metal oxides soluble in water
Insoluble apart from group one metals