Lesson Notes By Weeks and Term v4 - SHS 2
MATTER AND ITS PROPERTIES
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MATTER AND ITS PROPERTIES
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Subject: Chemistry
Class: SHS 2
Term: 1st Term
Week: 8
Grade code: 2.1.1.LI.5
Strand code: 1
Sub-strand code: 1
Content standard code: 2.1.1.CS.1
Indicator code: 2.1.1.LI.5
Theme: PHYSICAL CHEMISTRY
Subtheme: MATTER AND ITS PROPERTIES
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In our daily lives in Ghana, we observe changes happening at different speeds. The charcoal in a coal pot burns quickly to cook our banku, while the iron gate outside slowly rusts over many months. The fermentation of palm wine happens over a few days, not a few minutes. All these are chemical reactions, and the "speed" at which they happen is what chemists call the rate of reaction. Understanding this concept is crucial for controlling processes in industry (like producing medicines or fertilizers), in our kitchens (cooking and preserving food), and in protecting our environment. This lesson will introduce us to how we define, measure, and think about the speed of chemical reactions.
2.1 What is the Rate of a Reaction?
In simple terms, the rate of a reaction is a measure of how fast a reaction proceeds. Formally, we define it as:
> Rate of Reaction: The change in the concentration of a reactant or a product per unit time. Reactants are the substances we start with. As the reaction proceeds, their amount (or concentration) *decreases*. Products are the new substances formed. As the reaction proceeds, their amount (or concentration) *increases*.
The unit for the rate of reaction is typically moles per cubic decimetre per second (mol dm⁻³ s⁻¹) or sometimes moles per litre per second (mol L⁻¹ s⁻¹).