Summary EVERYTHING YOU NEED TO KNOW:CHEMISTRY(grade 12)

CHEMISTRY

DEFINITIONS:

 1 MOLE- 1 mole of any gas occupies 22,4 dm 3 at 0 °C (273 K) and 1 atmosphere (101,3 kPa)

 EMPIRICAL FORMULA- formula giving the proportions of the elements present in a compound but
not the actual numbers or arrangement of atoms.(simplified version)

 MOLECULAR FORMULA-Molecular formulas tell you how many atoms of each element are in a
compound (how it actually occurs in nature)


 Dipole-dipole forces: Forces between two polar molecules

 Induced dipole forces or London forces: Forces between non-polar
molecules

 Hydrogen bonding: Forces between molecules in which hydrogen is
covalently bonded to nitrogen, oxygen or fluorine – a special case of
dipole-dipole forces




 ELECTRONEGATIVITY- measure of the tendency of an atom to attract a bonding pair of electrons.

 INTERMOLECULAR-intermolecular forces exist between the molecules themselves

 INTRAMOLECULAR-intramolecular forces exist between atoms within a molecule



 ORGANIC MOLECULES- molecules that contain carbon atoms



 MOLECULAR FORMULA- formula that indicates the type of and number of atoms in a molecule



 STRUCTURAL FORMULA- A structural formula of a compound shows which atoms are attached to
which within the molecule. Atoms are represented by their chemical symbols and lines are used to
represent ALL the bonds that hold the atoms together.



 CONDENSCED STRUCTURAL FORMULA- formula that shows which atoms are connected to
which but without the use of bond lines

,  HYRDOCARBON- organic compound that only consists of hydrogen and carbon


 HOMOLOGOUS SERIES- a series of compounds that can be described by the same general
formula or where one member can be separated by the next by a ch2 group


 SATURATED COMPOUNDS- Compounds in which there are no multiple bonds between C atoms in
their hydrocarbon chains



 UNSATURATED COMPOUNDS- compounds in which there are multiple bonds between C
atoms in their hydrocarbon chains. Multiple bond can break and molecule could join with
something else, assimilating/ absorbing it hence it's unsaturated- not attatched to the max
number of atoms it could be attatched to


 FUNCTIONAL GROUP: A bond or an atom or a group of atoms that determine(s) the physical and
chemical properties of a group of organic compounds

 STRUCTURAL ISOMERS-Organic molecules with the same molecular formula, but different structural
formulae
-Chain isomers-Same molecular formula, but different types of chains
-Positional isomers-Same molecular formula, but different positions of the side chain
-Functional isomers- same molecular formula but different functional groups

 CRACKING- The chemical process in which longer chain hydrocarbon molecules are broken down 
to shorter more useful molecules The reaction type that can be used to convert hydrocarbons with
high molecular masses to hydrocarbons with low molecular masses.




 HYRDOLYSIS- reaction of a salt with water

 HEAT OF REACTION- (ΔH) energy absorbed or released in a chemical reaction.
 EXOTHERMIC REACTION-reactions that release energy.
 ENDOTHERMIC REACTIONS- reactions that absorb energy.

 ACTIVATION ENERGY- the minimum required energy for a reaction to take place