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Science and Technology, Class 9 · Chemical Reaction
Chemical Equations
Reactants and products · Word and formula equations · Balanced or unbalanced
By the end of this lesson you can
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Define a chemical reaction
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Pick out reactants and products
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Write word and formula equations
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Count atoms to test for balance
Three things atoms do in a reaction
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Combine: hydrogen + oxygen → water
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Break apart: calcium carbonate → calcium oxide + carbon dioxide
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Exchange: magnesium + hydrochloric acid → magnesium chloride + hydrogen
Presenter notes: Today we learn how to write a chemical reaction in a short, exact form.