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NUCLEUS
Contains PROTONS and NEUTRONS
Positive overall charge
Most of mass concentrated in nucleus

ATOMS
NO OVERALL CHARGE
EQUAL NUMBERS OF PROTONS AND ELECTRONS

ELECTRONS
NEGATIVE
Small mass
Occupy shells
Explain whole of chemistry
If electrons are added/removed atom becomes CHARGED and is than an ION

PROTONS
MASS- 1
POSITIVE…

Page 2

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ELECTRON SHELLS

Lowest energy levels always filled first
1st shell- 2.
2nd shell-8
3rd shell- 8
Atoms are happy when all shells are full
Noble gases- group 0- all full outer shells- unreactive
If an outer shell is not full the atom wants to REACT.

IONIC BONDING
Transferring electrons
Atoms…

Page 3

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INSOLUBLE
EXAMPLES OF GIANT COVALENT STRUCTURES:
DIAMOND
Each CARBON atom has 4 covalent bonds.
Very hard
GRAPHITE
Each CARBON atom has 3 Covalent bonds
Has layers- slide over each other easily
One electron is delocalized ­ allows graphite to conduct electricity and heat
SILICON DIOXIDE (SILICA)
What sand is made…

Page 4

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How heavy an atom is compared to mass of an atom of carbon-12
Just the mass number of atom
When an element has more than one stable isotope, the Ar is the average value of all the
different isotopes e.g. chlorine.
RELATIVE FORMULA MASS- Mr
All the mass numbers in…

Page 5

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ATOM ECONOMY

% OF REACTANTS CHANGED USEFULLY
Total Mr of useful products / total Mr of reactants X 100
High atom economy is better for profits and the environment
Reactions with low atom economy
1. Use up resources quickly
2. Make lots of waste materials to be disposed of
3.…

Page 6

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Makes reaction reach EQUILIBRIUM QUICKER but you have the same amount of product.

THE HABER PROCESS
Important industrial process
Produces AMMONIA (NH3)- makes fertilizers
Uses NITROGEN and HYDROGEN
NITROGEN- Found easily from air (78% nitrogen, 21% oxygen)
HYDROGEN- From Natural gas/ other resources e.g. crude oil
Reaction is reversible- not…

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Lowers activation energy- less energy needed to start reaction
Lower temperatures needed
Solid catalysts work best with a big surface area
Usually powder, pellets or a fine gauze- very large surface area
Transition metals-common catalyst in industrial processes
Reduce costs
1. Increases rate of reaction- saves money
2. Lower temperatures-…

Page 8

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Explains reaction rates
Rate of reaction depends on HOW OFTEN and HOW HARD the reacting particles COLLIDE
Chemical reactions can only occur when reacting particles collide with each other and with
sufficient energy

HIGHER TEMPERATURE INCREASES COLLISIONS

Particles move quicker when the temperature is increased
Increases ENERGY ­ Particles mover…

Page 9

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Whenever CHEMICAL REACTIONS occur ENERGY is usually TRANSFERRED to or from
surroundings

EXOTHERMIC REACTIONS
Heat is given out
Usually shown by a raise in temperature
a. BURNING FUELS (COMBUSTION)- Gives out a lot of heat
b. NEUTRALISATION REACTIONS- (Acid and alkalis)
c. OXIDATION REACTIONS- (Adding water to COPPER SULPHATE to…

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