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Additional



Science revision
booklet

By Rainu Kaur








Chemistry

Rates of reactions
The rate of a reaction measures the speed of a reaction.
As the reactions takes place the mass will decrease, if a gas is given off we can measure
the rate of reaction by collecting the gas and measuring…

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Factor Reactions affected Change made in Effect on rate of
condition reaction
CATALYST Slow reactions that Reduces the amount of Increases rate of
can be speeded up energy required for reaction so that
by adding a suitable reaction to take place more collisions can
catalyst (activation energy) happen.
CONCENTRATION All…

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If the concentration of a solution is increased there are more particles dissolved in
the same volume. This means the dissolved particles are closer together and so they
collide more often.
Double concentration of acid
Double number of particles
Double chance of collisions
Double the rate of reaction

Effect of…

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A+B C + D





Two arrows are used to show the reaction is both forward and reverse
When there is no change in the amount of products and reactants (forward
and reverse at the same rate) EQUILIBRIUM is reached.
Example: Hydrochloric acid + Ammonia Ammonium Chloride
Double arrows means its…

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The conditions which give the best profits for the manufacturers mean a
compromise for the conditions. Temperature gives a faster rate but reduces yield.
Pressure gives a faster rate and yield but is expensive.

TEMPERATURE 450 c = FASTER RATE, LOWER YIELD

PRESSURE 220 atm = FASTER RATE, GREATER YIELD,…

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form a COVALENT bond to make a bromine molecule Br . In electrolysis REDUCTION
and OXIDATION happen we call it REDOX.

At the cathode: Pb + 2e Pb
At the anode: 2Br Br + 2e

Electrolysis of Brine
Brine is a solution of sodium chloride in water. The electrolysis of…

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The half equations for the reactions at the electrodes are:
At the positive electrode the anode: Cu(s) Cu (aq) + 2e
At the negative electrode the cathode: Cu (aq) + 2e Cu(s)

Acids and Alkalis









Universal indicator is used to determine pH we can then use it to see whether…

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ACID + METAL SALT + HYDROGEN
E.g. Hydrochloric acid + Magnesium Magnesium chloride + Hydrogen

Neutralisation
OH + H H 0

ACID + ALKALI SALT + WATER
E.g. Hydrochloric acid + Sodium Hydroxide sodium chloride + water

(aq) = In solution (dissolved)
(l) = liquid
(s)= solid
(g) = gas…

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Electrical Power = voltage ÷ Current



Mains electricity

Blue goes left, brown goes right and striped goes to the top.












The mains electricity supply is 230V.

When you plug in something with a metal case into a wall socket you automatically
`EARTH' the metal case which means it is connected…

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You will get an electric shock if the live wires touch the metal case (the outer
layer)

The Fuse
The fuse breaks the circuit if the current is too high.
The fuse melts easily then breaks the circuit
Fuses have common ratings; most common are 3A, 5A, 10A, 13A
Fuse…

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