Collecting gases
The method used to collect a particular gas depends on
1) Is the gas more or less dense than air?
2) Is the gas soluble in water?
Method
Use when ...
Upward displacement
Downward
Over water
Gas syringe
of air
displacement of air
gas is denser than air
gas is less dense than
gas is insoluble or only
you want to measure the
air
slightly soluble in water
volume
Apparatus
Gas syringe
Gases
Carbon dioxide (CO2)
Hydrogen (H2)
Hydrogen (H2)
collected by
Chlorine (Cl2)
Ammonia (NH3)
Oxygen (O2)
this method
Carbon dioxide (CO2)
All gases
Using the information provided decide which method(s) can be used to collect each gas. Write the name of the gas in the table
under the appropriate method.
(Note: more than one method can be used for all gases)
Hydrogen (H2) is less dense than air and is almost insoluble in water.
Oxygen (O2) has almost the same density as air and is only slightly soluble in water.
Carbon dioxide (CO2) is denser than air and only slightly soluble in water.
Chlorine (Cl2) is denser than air and soluble in water. It is less soluble in salt solution.
Ammonia (NH3) is less dense than air and extremely soluble in water.