5.2 decomposition

• Scheikunde
• Middelbare school
• vwo
• Leerjaar 3

5.2 Decomposition

Planning

• Difference between combustion and decomposition
• Information about three types of decomposition
• Checking quiz

Lessongoals

• Learn about three types of decomposition.
• Understand what the differences are between combustion and decomposition.

What happened to the sausages?

Heating substances, what can happen:

• Phase transition 
• Separation 
• Combustion
• Decomposition

Decomposition

• Chemical reaction with only one reactant (so no oxygen!).
• Reaction stops when you stop adding energy.
• You do not see fire, nor is there energy formed

Chemical reaction

Reactant --> decomposition products

Three types of decomposition

• Thermolysis (with heat)
• Electrolysis (with electricity)
• Photolysis  (with light)

So the previous slides where mostly about thermolysis, because it is sometimes mixed up with combustion this requires some extra focus.

During the ironing of a shirt with an iron which is too hot there form scorchmarks. This is a ...

1. Thermolysis
2. Electrolysis
3. Photolysis
4. No decomposition

A couple of years after installation a brightly coloured curtain has become faded in colour. This happened due to ...

1. Thermolysis
2. Electrolysis
3. Photolysis
4. No decomposition

When you heat up glass to a really high temperature you can shape it into another form, this is ...

1. Thermolysis
2. Electrolysis
3. Photolysis
4. No decomposition

With the help of electicity aluminium is made from bauxite ore. This is ...

1. Thermolysis
2. Electrolysis
3. Photolysis
4. No decomposition

Go and do the exercises of paragraph 5.2