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Charlotte Jones Atmosphere Module Notes 18/04/13




Atmosphere ­ Notes for Chemistry Salters B
6.2 ­ What happens when radiation interacts with matter?
INTRO
Changes to molecules depend on:
o Molecule involved
o The amount of energy involved.
Changes can include:
o TRANSLATION ­ molecule moving around
o ROTATION ­ molecule…

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Charlotte Jones Atmosphere Module Notes 18/04/13




6.3 ­ Radiation and Radicals
WAYS OF BREAKING BONDS (BOND FISSION)
o HETEROLYTIC fission
Both of the shared electrons go to one of the atoms.
Leaves a +ve and a ­ve atom
Most common when a bond is POLAR
o HOMOLYTIC fission
Electrons are…

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Charlotte Jones Atmosphere Module Notes 18/04/13




10.1 ­ Factors affecting reaction rates
FACTORS AFFECTING RATE




CONCENTRATION
o The higher the concentration the faster the rate of reaction as there's a
greater chance of reactants colliding and more collisions take place.
TEMPERATURE
o The higher the temperature, the faster the rate…

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Charlotte Jones Atmosphere Module Notes 18/04/13




10.2 ­ The effect of temperature on rate
RAISING THE TEMPERATURE
o Molecules move faster, so they collide more frequently.

o Average speed of molecules is proportional to


o Molecules collide with more energy, so activation energy is reached easier.

GRAPHS TO SHOW HOW…

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Charlotte Jones Atmosphere Module Notes 18/04/13




10.5 ­ What is a catalyst?
TYPES OF CATALYSTS
o HETEROGENEOUS
Heterogeneous catalysts are in a DIFFERENT PHASE to the
reactants. (Different state)
The reaction (if solid catalyst and gaseous reactants) will
take place on the surface of the catalyst.
The process is shown…

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Charlotte Jones Atmosphere Module Notes 18/04/13




o Existing bonds are stretched and broken.
o New bonds are formed.
o BOND BREAKING is ENDOTHERMIC (it uses energy)
o BOND MAKING is EXOTHERMIC (releases energy)
o Catalysts speed up reactions by providing an alternative reaction pathway.
o This allows more molecules to…

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Charlotte Jones Atmosphere Module Notes 18/04/13




POSITION OF EQUILIBIRUM
o The position of the equilibrium depends on various factors
CONCENTRATION of solutions
PRESSURE of gases
TEMPERATURE
CONCENTRATION
o If the reactant concentration on one side of the reaction is increased, more
products will be made to counteract it.
Increasing the…

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Charlotte Jones Atmosphere Module Notes 18/04/13




o SO2 has STRONG intermolecular bonds as it forms COVALENT BONDS
between molecules, making it hard to break apart. Thus it is a SOLID at room
temperature.
COVALENT MOLECULAR STRUCTURES ­ eg. CO2
o Consist of DISCRETE MOLECULES
o Strong covalent bonds between atoms…

Comments

john k

Thanks for this, it's a great resource. 

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