1.2 how are gases collected

Question 1

factors affecting how we collect gas

Answer 1

solubility and density

Question 2

solubility

Answer 2

how easily the gas dissolves in water

Question 3

density

Answer 3

how dense the gas is compared to the surrounding air

Question 4

methods for collecting gas (excluding using a gas syringe)

Answer 4

water displacement
downward delivery
upward delivery

Question 5

water displacement

Answer 5

-for gas insoluble/ slightly soluble in water
-density does not affect gas collection

Question 6

examples of gas collected by water displacement

Answer 6

hydrogen, oxygen, carbon dioxide

Question 7

downward delivery

Answer 7

-can collect soluble or insoluble gases
-collects gases denser than air

Question 8

example of gases collected by downward delivery

Answer 8

chlorine, hydrogen chloride, sulfur dioxide

Question 9

upward delivery

Answer 9

-collect soluble or insoluble gases
-collects gases less dense than air

Question 10

examples of gas collected by upward delivery

Answer 10

ammonia

Question 11

methods for drying gas

Answer 11

concentrated sulfuric acid
quicklime (calcium oxide)
fused calcium chloride

Question 12

concentrated sulfric acid

Answer 12

• works for most gases including chlorine and hydrogen chloride
  -not suitable for gases that react with sulfuric acid (eg. ammonia)

Question 13

quicklime (calcuim oxide)

Answer 13

-drys ammonia
-absorbs moisture and carbon dioxide from air so it must be heated before use. it cannot be used to dry gases which react with calcium oxide (eg. carbon dioxide)

Question 14

fused calcium chloride

Answer 14

-drys gases like hydrogen, nitrogen and carbon dioxide
-readily absorbs ,moisture from the air so it just be heated before use. it cannot be used to dry gases that react with calcium chloride (eg. ammonia)