Experimental Techniques

How to measure Mass?

• Beam balance

• Electronic balance

How to measure time?

• Analogue stopwatch

• Digital stopwatch

How to measure temperature?

• Mercury/Alcohol thermometer

• Digital thermometer

• Data logger

How to measure volume?

• Measuring cylinder

• Burette - Very accurate to 0.05cm³

• Pipette - Fixed volumes of liquid (typically 20.0cm³ or 25.0cm³

How to measure gas?

Gas syringe

1. Plunger moves outwards when gas is released

2. Measure reading on barrel

3. Max volume of 100cm³

When to use Displacement of Water to collect gas?

When collecting gases insoluble of water

When to use Downward delivery of gas?

When collecting gases denser than air

When to use Upward delivery of gas?

When collecting gas less dense than air

Gases that are not or only slightly soluble

1. Hydrogen

2. Oxygen

3. Carbon dioxide

Gases that are very soluble

1. Chlorine

2. Hydrogen

3. Sulfur dioxide

4. Ammonia

When to dry gas with Concentrated sulfuric acid?

Most gases can be used, except gases that react with acids (alkalis, ammonia)

When to dry gas with Calcium Oxide (Quicklime)?

Basic, alkaline gases and ammonia. Not suitable for gases that react with a base (acidic gases). Must be heated before use to make sure it is dry.

When to dry gas with Fused calcium chloride?

Most gases can be used, except acidic and basic gases, as well as ammonia.