Lesson Notes By Weeks and Term v4 - SHS 3
MATTER AND ITS PROPERTIES
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MATTER AND ITS PROPERTIES
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Subject: Chemistry
Class: SHS 3
Term: 1st Term
Week: 12
Grade code: 1.1.1.LI.2
Strand code: 1
Sub-strand code: 1
Content standard code: 1.1.1.CS.2
Indicator code: 1.1.1.LI.2
Theme: PHYSICAL CHEMISTRY
Subtheme: MATTER AND ITS PROPERTIES
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This lesson introduces the fundamental concept of the Atomic Mass Unit (AMU). Atoms are incredibly small and light, making it impossible to weigh them using everyday scales like those we use to buy yam or fish at the market. To solve this, chemists developed a relative scale to compare the masses of atoms. Just as the kilogram is a standard for measuring mass in our daily lives, the Carbon-12 atom is the universal standard for measuring mass at the atomic level. Understanding this concept is the foundation for almost all quantitative chemistry, from calculating yields in industrial processes in Tema to formulating medicines in our hospitals.
2.1 The Problem: Weighing the Unweighable
Atoms are the basic building blocks of all matter. They are unimaginably small. For instance, a single 1 pesewa coin contains more atoms than there are grains of sand on all the beaches in Ghana.
The actual mass of a single proton or neutron is about 1.67 x 10⁻²⁴ grams. This is a tiny, inconvenient number to work with in daily calculations. Imagine telling a pharmacist to measure out 0.0000000000000000000000167 grams of a substance! It is impractical. 2.2 The Solution: A Relative Mass Scale
To overcome this, scientists created a *relative scale*. Instead of using the actual, tiny mass in grams, they decided to compare the mass of every atom to a chosen standard.