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What is an element?
- a substance that cannot be broken down into other substances
- There are 109 elements
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What is an atom?
Smallest particle of an element
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What is a molecule?
- The smallest particle of substance that can exist by itself and has all the properties of that substance.
- Oxygen, hydrogen, nitrogen and chlorine molecules are made of 2 atoms each.
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What is a compound?
- Made up of 2 or more elements that have been chemically combined.
- The elements lose their individual identities when they are joined. The compound has new different properties.
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What is a mixture?
A combination of 2 or more substances that keep their own properties.
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What are the common compounds?
acids, bases, salts and oxides
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acid
- contains hydrogen ions (H+)
- usually has a sour taste
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examples of acids
vinegar and lemon juice
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common acids
- sulfuric acid (H2SO4)
- nitric acid (HNO3)
- carbonic acid (H2CO3)
- acetic acid (HC2H3O2)
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Sulfuric acid
- H2SO4
- used in medicines, alcohol, dyes, and car batteries
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nitric acid
- HNO3
- used in fertilizers, explosives, and cleaning materials
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acetic acid
- HC2H3O2
- used in making plastics, rubber, photographic film, and as a solvent
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Bases
- contain hydroxyl ions (OH-)
- bitter taste and stronger ones feel slipper
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example of Bases
household cleaning products
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common bases
- sodium hydroxide (NaOH)
- ammonium hydroxide (NH4OH)
- potassium hydroxide (KOH)
- calcium hydroxide (Ca (OH)2)
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Sodium Hydroxide
- NaOH
- used in making soap, paper, vegetable oils and refining petroleum
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Ammonium Hydroxide
- NH4OH
- making deodorants, bleaching compounds and cleaning compounds
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Potassium Hydroxide
- KOH
- making soaps, drugs, dyes, alkaline batteries and purifying industrial gasses
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Calcium Hydroxide
- Ca(OH)2
- making cement and plaster
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What is an indicator
a substance that changes color when it comes into contact with a base or acid
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Litmus Paper
- blue litmus paper turns red in an acid
- red litmus paper turns blue in a base
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How is salt formed?
When an acid and a base combine chemically.
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Oxides
- formed when oxygen combines with another element
- ex: rust forms when oxygen combines with iron
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Chemical Reactions
- 1 or more substances are formed
- energy is released during reaction
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Chemical Equalibrium
when the quantities of reactants and products are at a steady state
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