Sci 9 Exam 3rdTerm

• Octet rule


  Atoms tend to have eight electrons in valence shell
• Ionic bonding


  Result from the interaction of metals with nonmetals
• Characteristics of ionic compounds

  • High melting point
  • Hard but brittle
  • Molten state conduct electricity
  • Solid state does not conduct electricity
  • Dissolve in water
• When naming ionic compounds, write the name of cation first, followed by the anion ending in -ide
• Covalent bonding


  Formed by sharing a pair of electrons, can exist as single, double, and triple bonds
• When naming covalent compounds, use prefixes to indicate how many atoms of each element are shown in the formula
• Prefixes for number of atoms

  • Mono (1)
  • Di (2)
  • Tri (3)
  • Tetra (4)
  • Penta (5)
  • Hexa (6)
  • Hepta (7)
  • Octa (8)
  • Nona (9)
  • Deca (10)
• Characteristics of covalent compounds

  • Exist as gases or liquids or soft solids
  • Melting and boiling points are generally low
  • Insoluble in water but dissolve in organic solvents
  • Non-conductors of electricity in the solid state
• Metallic bonding


  The way that metal atoms are kept together within a metal material, caused by the valence electrons
• Properties of carbon


  • Can accommodate four bonds (tetravalent) because it has four valence electrons
  • Can bond with itself, thus, can form long chains of carbons
  • Can form bonds with other nonmetals
  • Can form multiple bonds with itself (double bonds and triple bonds)
• Hydrocarbons


  Most common organic compounds, composed of carbon and hydrogen atoms only
• Types of hydrocarbons


  • Alkane - all single bonds
  • Alkene - with at least one double bond
  • Alkyne - with at least one triple bond
• When naming hydrocarbons, use prefixes to indicate the number of carbons
• Aliphatic hydrocarbons


  Do not contain benzene ring
• Aromatic hydrocarbons


  Contain benzene ring
• Benzene ring


  Characterized by six carbons connected in a ring with alternating double bonds
• Types of chemical equations

  • Combination (synthesis)
  • Decomposition
  • Single replacement (single-displacement)
  • Double replacement (double-displacement)
  • Combustion
• We balance a chemical equation to satisfy the law of conservation of mass
• Properties of gases


  • Low density
  • Indefinite shape and volume
  • Pressure
  • Compressibility
  • Expandability
  • Diffusivity
• Gas laws


  • Boyle's law (relationship between pressure and volume)
  • Charles' law (relationship between temperature and volume)
  • Gay-Lussac's law (relationship between temperature and pressure)
• Fractional distillation


  Type of distillation which involves the separation of miscible liquids, involves repeated distillations and condensations, the mixture is usually separated into component parts
• The basic principle of fractional distillation is that different liquids boil and evaporate at different temperatures
• Miscible liquids


  Fully mixed in all proportions
• Petroleum fractions


  • LPG (liquefied petroleum gases)
  • Petrol
  • Naphtha
  • Kerosene
  • Diesel
  • Fuel oil
  • Bitumen
• Atmosphere


  The layer of gas that envelops the Earth, contains all the important gases that we need to survive
• Ozone depletion


  Thinning of the ozone layer, caused by the interaction of chlorine and bromine with the ozone in the atmosphere
• Chlorofluorocarbons


  Contains carbon, chlorine, and fluorine atoms, found in paint spray cans and aerosol sprays
• Greenhouse gases


  Trap the heat coming from Earth from bouncing into space
• Acid rain


  Formed when sulfur dioxide and nitrogen dioxide undergo oxidation and react with water, resulting in the formation of sulfuric acid and nitric acid
• Liquefied petroleum gases (LPG)


  Consists of propane and butane and used as bottled gas for cooking and heating
• PETROL


  Used as a fuel for car engines
• NAPHTHA


  Essential to contemporary industry, used in everything from petroleum-based burner fuel to the production of plastics and medications
• KEROSENE


  • Used as a fuel for jet engines in aircraft
  • Also called paraffin in some areas of the world and is used in lamps
• DIESEL


  Used as a fuel for vans, lorries and trains
• FUEL OIL


  Used as a fuel for ships, for heating and in power stations
• METALLIC BONDING - is the way that metal atoms are kept together within a metal material. A metallic bond is a type of chemical bond similar to a covalent bond. Atoms in metals are held together by forces caused by the valence electrons.
• Properties of Metallic Bonding

  • Malleable and ductile
  • Electrical conductivity
  • Thermal conductivity
  • Lustrous
  • Solid at room temperature except mercury
• COMBINATION – also known as a synthesis reaction, is a reaction in which two or more substances combine to form a single new substance.
• DECOMPOSITION – is a reaction in which a compound breaks down into two or more simpler substance. 
• SINGLE REPLACEMENT – also known as single-displacement, is a reaction in which one element replaces a similar element in a compound.