Oxygen, Hydrogen and Testing for Ions and Gases Flashcards
1
Q
How do you test for sulphates?
A
- precipitation reaction with barium chloride + dilute HCl(rules out a carbonate)
- white precipitate produced
2
Q
How can you know that manganese(IV) oxide was used up?
A
- weigh, filter, dry and weigh again
3
Q
How do you test for water?
A
- anhydrous copper(II) sulfate: white powder turns blue in presence of water
- cobalt chloride: blue turns pink in presence of water
4
Q
How do you used iron or phosphorus to investigate the proportion of oxygen in the atmosphere?
A
- iron reacts with oxygen in the air to form rust
1. first soak some iron wool in acetic acid (a catalyst). then push the wool into a test tube, put your thumb over the end and invert the tube into a beaker of water
2. over time, the level of water in the test tube will rise
3. iron reacts with oxygen in the air and water rises to fill the space the oxygen took up
4. you need to mark the start and finish of the water
5. calculate percentages
5
Q
What is CO2 used for?
A
- carbonated drinks: slightly soluble in water and dissolves in drink under high pressure. produces a slightly acidic solution due to formation of carbonic acid
- fire extinguishers: CO2 more denser than air, so it sinks onto the flames and stops the oxygen from getting to the fire
6
Q
How do you test for Copper(II), Cu2+?
A
- precipitation reaction with sodium hydroxide, NaOH
- blue precipitate produced
7
Q
What are greenhouse gases?
A
- gases that absorb heat that would normally be radiated out of space, acting as an insulating layer
8
Q
How do you test for hydrogen?
A
- makes a squeaky pop with a lighted splint
9
Q
What colour precipitate do you have when you test for bromide?
A
- cream precipitate
10
Q
How do you test for ammonia?
A
- turns damp red litmus paper blue and pungent smell
11
Q
What happens when you react carbon with oxygen?
A
- produces an orange/yellow flame
- produces CO2 gas
- slightly acidic when dissolved in water
12
Q
How do you test for carbon dioxide?
A
- turns limewater cloudy
13
Q
How do you test for carbonates, CO3^2-?
A
- precipitation reaction with dilute HCl
- white precipitate formed, CaCO3
- lime water turns cloudy because CO2 produced
14
Q
How do you test for chlorine gas?
A
- chlorine bleaches damp litmus paper
15
Q
How do you test for oxygen?
A
- relights a glowing splint