Rate = 1/time

-energy above the activation energy 

-collision of particles at the correct angle or orientation

the minimum amount of energy required for a reaction

the unstable intermediate between reactants and products containing partial bonds

HP- HR

(enthalpy of products - enthalpy of reactants)

Catalysts lower the activation energy increasing the number of particles able to react

They work by adsorbing reactants onto active sites which weakens their bonds.

Poisoning occurs when chemicals are absorbed onto active sites stopping them working

 Enzymes can be denatured if the pH, temperature or alcohol content is too extreme

Define each component /\H=cm/\T

ΔH is enthalpy change

c is 4.18 Kj/mol

m is number of kilograms (litres) of water

ΔT is the temperature change

work out how much 1 mole would produce

there is an extra energy level moving the electrons further from the nucleus thus increasing the size

It increases across a period as the electrons are closer to the nucleus therefore harder to remove

It decreases down a group as the electrons are further from the nucleus and shielded from its pull by the inner electrons

There is a large jump between the first and second ionisation energies for group 1 metals as you are removing an electron from an energy level closer to the nucleus

It increases across a period as the nuclear charge increases pulling the electrons closer

It decreases down a group as the pull of the nucleus is being shielded by the inner electrons

Pure covalent bonds

POLAR covalent bonds

The atoms with the biggest electronegativities have a δ-charge and those with the lowest value have a δ+ charge.

Metallic bonds have positive cores surrounded by delocalised electrons enabling the metals to conduct.

This force of attraction is very strong and exists in metal elements.

Ionic bonds are an electrostatic force of attraction between oppositely charged ions.

They have high melting points and have a crystal lattice structure that must be broken before the ions are free to move and conduct electricity.

Ionic compounds are soluble in polar solvents like water

Covalent bonds are very strong and difficult to break

Covalent network substances have massive structures with millions of bonds which have to be broken to change their state

•Covalent molecular substances are usually liquid or gas at room temperature.

•It is weak intermolecular forces that are broken when their state is changed

Dipole –Dipole attractions are caused by molecules that have a permanent dipole

They are stronger than Van der Waals.

They are the weakest intermolecular force

6.02x1023 formula units

6.02x1023 atoms

6.02x1023 molecules

6.02x1023 formula units

Stays the same

We can use simple ratios to work out the volumes of gases from a balanced equation