chpt 1 experimental design

Question 1

What are the methods of gas collection ?

Answer 1

1. downward delivery
2. upwards delivery
3. gas syringe
4. water displacement

Question 2

How does downwards delivery work ?

Answer 2

1. for gases denser than air and soluble in water
   eg cl, h+

Question 3

How does upwards delivery work ?

Answer 3

1. from gases denser than air and soluble in water
   eg ammonia, hydrogen and helium

Question 4

How does water displacement work ?

Answer 4

1. from gases insoluble / slightly soluble in water
   eg hydrogen and O2

Question 5

How does gas syringe work ?

Answer 5

1. collects most gases and measures their volume

Question 6

What are the methods to dry gases ?

Answer 6

1. conc sulfuric acid
2. quicklime (calcium oxide)
3. fused calcium chloride

Question 7

How does conc sulfuric acid work ?

Answer 7

1. dry gases except for alkali ones
2. if dries alkali, neutralisation rxn will occur

Question 8

How does quicklime (calcium oxide) work ?

Answer 8

1. used mainly to dry ammonia gas
2. do not use to dry acidic gases bc neutralisation rxn will occur

Question 9

How does fused calcium chloride work ?

Answer 9

1. used mainly to dry most gases except for ammonia
2. calcium chloride reacts with ammonia so drying does not take place