When atoms react by creating chemical bonds, they form molecules.
The molecules formed from chemical reactions are completely different substances with different properties.
Ex. Na which is explosive and Cl which is poisonous combine to form common table salt.

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​Compounds

Compounds have common names and chemical names. Ex. Ferrous Oxide is commonly called rust.
Compounds also have chemical formulae. Ex. H₂O, Fe₂0₃

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Chemical Names and Formulae

Chemical change or chemical reaction happens when atoms combine and create different substances.
Ex. Vinegar and baking soda form carbon dioxide and sodium acetate

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​Chemical Change

Chemical equations show which substances are used in a chemical reaction.
It also shows at the ratio of the substances.
Reactants - the substances on the left.
Products - the resulting substances on the right.
Law of conservation of mass - the mass of the reactants and products are equal.

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​Chemical Equations

Signs of Chemical Change

Change in Color

Tarnishing

Releases Gas

Forms a Precipitate

Releases Energy

Photosynthesis
Cellular respiration
Digestion
Combustion (fuel)
Batteries
Creation of Compounds (petrol products, plastics, etc.)

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​Everyday Chemical Reactions

Cooking and baking
Cleaning
Medicine
Traditional photography
Fermentation

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​Everyday Chemical Reactions