Chem Unit 1

Chem Unit 1

C1.1
1. Atoms
  1. All substances are made from atoms
    1. A substance made from only one type of atom is called an element
  2. Each atom has its own chemical symbol
  3. Each atom has it's own different charge
    1. Proton = +1
    2. Neutron = neutral
    3. Electron = -1
  4. There are always an equal number of protons and electrons
    1. Atoms have no overall electrical charge
  5. The number of protons in an atom is its atomic number
    1. The sum of protons and neutrons is its mass number
  6. Electrons are in energy levels around the nucleus of an atom
    1. In the first energy level there are only a maximum two electrons
      1. In all the others there are a maximum of eight
2. Periodic table
  1. Elements in the same group of the periodic table have the same number of electrons in their out energy level
  2. Elements in group 0 are called nobel gasses
    1. They are very unreactive
    2. All of their outer energy levels are full
3. Chemical reactions
  1. When elements react, their atoms join with other atoms to form compounds
    1. This involves giving, taking or sharing electrons
  2. Chemical reactions can be represented by word or symbol equations
  3. No atoms are lost or made during a chemical reaction
    1. Meaning the mass of the products equals the mass of the reactants
C1.2
1. Calcium carbonate
  1. Lime stone is mainly composed of valium carbonate
    1. CaCO3
  2. Calcium carbonate can be decomposed by heating (thermal decomposition)
    1. This produces calcium oxide and CO2
  3. The carbonates of magnesium, copper, zinc, calcium and sodium decompose on heating in a similar way
  4. When calcium oxide is mixed with water calcium hydroxide is produced
    1. This is an alkali that can be used to neutralise acids
    2. Also known as limewater
      1. Limewater can be used as a test for CO2
        If it turns cloudy CO2 is present
  5. When calcium hydroxide is mixed with CO2 calcium carbonate is created
  6. When CaCO3 is mixed with acids CO2, salt and water are produced
  7. Heated Limestone makes cement
    1. Cement is mixed with sand to make mortar
    2. Cement is mixed with sand and aggregate to make concrete
C1.3
1. Extracting metals
  1. Metals are only extracted from their ore if there is enough of the metal in it
  2. Ores are mined and may be concentrated before the metal is extracted from them
  3. Most unreactive metals are found as metals not ores
  4. Metals that are less reactive than carbon are extracted via reduction
  5. Metals that are more reactive than carbon are extracted via electrolysis
  6. Copper
    1. Copper can be extracted by phytomining or by bleaching
    2. Copper can be obtained from solutions of copper salts by electrolysis or by displacement using scrap iron
  7. We should recycle materials as we have limited resources, it uses a lot of energy and it effects the environment
2. Alloys
  1. Iron
    1. Iron from a blast furnace contains about 96% iron
      1. Its impurities make it brittle
    2. Most iron is converted into steel
  2. Alloys are used as pure metals are too soft
3. Properties and uses of metals
  1. ls are good conductors of heat and electricity and can be bent into any shape
  2. Copper has properties which make it useful for electrical wiring and plumbing

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