C12.3 - Testing for gases Flashcards
Many of the reactions you study in chemistry do?
Many of the reactions you study in chemistry give off gases as a product
Many of the reactions you study in chemistry give off gases as a product.
So what have chemists done?
Chemists have devised:
1. Quick
2. Easy
tests to identify different gases
What is the reaction between zinc and dilute acid a convenient way to do?
The reaction between:
1. Zinc
2. Dilute acid
is a convenient way to make some hydrogen gas to test
The reaction between zinc and dilute acid is a convenient way to make some hydrogen gas to test.
The word equation for zinc and dilute acid
The word equation for zinc and dilute acid is:
Zinc + Sulfuric acid —> Zinc sulfate + Hydrogen
The reaction between zinc and dilute acid is a convenient way to make some hydrogen gas to test..
What can you do, if you want the gas to be produced more quickly?
If you want to gas to be produced more quickly:
1. A few crystals of copper(II) sulfate can be added
Or,
2. Magnesium can be used instead of zinc
The positive test for hydrogen
The positive test for hydrogen is that a lighted splint ‘pops’
A convenient way to make some oxygen gas to test
A convenient way to make some oxygen gas to test is the decomposition of hydrogen peroxide solution, with a little manganese(IV) oxide added as a catalyst
Positive test for oxygen
The positive test for oxygen is that a glowing splint relights
When asked how to identify a given gas, what do you always do?
When asked how to identify a given gas, you always give:
- The test
- Its result
How can you make carbon dioxide gas to test?
You can make carbon dioxide gas to test by reacting:
- Marble chips (calcium carbonate)
- Dilute hydrochloric acid
You can make carbon dioxide gas to test by reacting marble chips (calcium carbonate) and dilute hydrochloric acid.
The word equation for marble chips (calcium carbonate) and dilute hydrochloric acid
The word equation for marble chips (calcium carbonate) and dilute hydrochloric acid is:
Calcium carbonate + Hydrochloric acid —> Calcium chloride + Water + Carbon dioxide
Positive test for carbon dioxide gas
The positive test for carbon dioxide gas is that limewater turns milky (cloudy white)
Why must care be taken when working with chlorine?
Care must be taken when working with chlorine, because chlorine is a toxic gas
Positive test for chlorine gas
The positive test for chlorine gas is that damp blue litmus paper turns white (as it gets bleached)
A convenient way to make some oxygen gas to test is the decomposition of hydrogen peroxide solution, with a little manganese(IV) oxide added as a catalyst.
What will it produce?
It will produce:
- Oxygen
- Water
