1. Types of Chemical Reactions

2. Review: Evidence of Chemical Change
The following images illustrate some examples of evidence that a chemical change has occurred. Gas formation – usually observed as bubbles Precipitation formation – an insoluble solid formed during a reaction Odour change – a new smell being produced Energy production – the production of light or heat by a reaction

3. Types of Reactions
We will talk about four types of chemical reactions:
Synthesis reactions
Decomposition reactions
Single displacement reactions
Double displacement reactions
You need to be able to identify the type of reaction and predict the product(s)

4. 1 – Synthesis Reactions
A synthesis reaction is a chemical reaction in which two or more reactants (usually elements) combine to produce a new product. Example: hydrogen + oxygen  water

6. Example #1
Predict the products. Write and balance the following synthesis reaction equation. Sodium metal reacts with chlorine gas

7. 2 – Decomposition Reactions
A decomposition reaction is a chemical reaction in which a compound decomposes (breaks down) into two or more simpler compounds or elements. Example: water  hydrogen + oxygen

9. Example #2
Predict the products. Write and balance the following decomposition reaction equation: Lead (IV) oxide decomposes

10. 3 – Single Displacement Reactions
A single displacement reaction is a chemical reaction in which one element (a reactive metal or non-metal) takes the place of an element in a compound to produce another element and another compound.
A + BC AC + B
Where A is a metal
A + BC BA + C
Where A is a non-metal

12. Activity Series
The activity series is a list of elements organized according to their chemical reactivity. The most reactive element appears on the top, and the least reactive appears at the bottom. Metals higher up on the activity series list will replace metals lower on the list during a single displacement reaction.

13. Example #3
Predict the products. Write and balance the following single displacement reaction equation: Zinc metal reacts with hydrogen monochloride

14. 4 – Double Displacement Reactions
A double displacement reaction is a chemical reaction in which the positive ions of two different compounds exchange places, resulting in the formation of two new compounds – one of which may be a precipitate (an insoluble solid).
Producing silver chromate (AgCrO4(s) ) (the red precipitate) and potassium nitrate (2KNO3(aq))

15. Example #4
Predict the products. Write and balance the following double displacement reaction equations:
Silver nitrate and sodium chloride
Potassium sulfate and barium nitrate

16. Summary of Reaction Types

17. Combustion Reaction
One additional type of chemical reaction that you will learn more about in grade 11 is a combustion reaction. These reactions always involve a “fuel” reacting with oxygen to release energy. Carbon dioxide and water are also produced by the reaction. CH4(g) + 2 O2(g)  CO2(g) + 2 H2O(l)