Experimental Design

Question 1

Name the 3 apparatus used to measure liquids.

Answer 1

Burette, pipette, measuring cylinder

Question 2

If I want to measure 28.85cm³ of a liquid, what apparatus should I use and why?

Answer 2

Burette. It measures to the nearest 0.05cm³.

Question 3

When can I use a pipette?

Answer 3

Pipette can only measure fixed volumes of liquids. Pipettes come in different sizes and usually hold 10.0, 20.0 or 25.0cm³, depending on the fixed volume it is supposed to measure.

Question 4

If I want to measure 17.5cm³ of liquid, what apparatus should I use and why?

Answer 4

Measuring cylinder. It measures to nearest 0.5cm³.

Question 5

Name the 3 methods of collecting gases.

Answer 5

1. Displacement of water
2. Upwards delivery
3. Downwards delivery

Question 6

What type of gases does displacement of water collect? How does it do so? Give examples of such gases.

Answer 6

Gases which are insoluble/slightly soluble in water. As the gases do not dissolve in water, they will rise to the top of the gas jar. Some examples of gases collected via this method includes H2, O2, CO and CO2.

Question 7

What type of gases is upwards delivery used to collect? Give examples of such gases.

Answer 7

This method is used to collect gases which have a lighter density as compared to air. NH3 and H2 are gases which can be collected using this method.

Question 8

What type of gases is downwards delivery used to collect? Give examples of such gases.

Answer 8

This method is used to collect gases which have a heavier density as compared to air. Some examples of gases collected using this method includes CI2, HCI and SO2.

Question 9

To dry a sample of gas, what are the 3 drying agents we can pass it through?

Answer 9

1. Concentrated sulfuric acid
2. Quicklime (calcium oxide)
3. Fused calcium chloride

Question 10

Concentrated sulfuric acid can only be used to dry what type of gases?

Answer 10

Acidic gases

Question 11

Quicklime (calcium oxide) can only be used to dry what type of gases?

Answer 11

Alkaline gases (mainly ammonia)

Question 12

Why is fused calcium chloride the best drying agent to dry gases?

Answer 12

It can dry most gases since it is neutral.

Question 13

What will happen if you use the wrong drying agent to dry a gas?

Answer 13

The gas will neutralise with the drying agent instead.