chem key facts u have to know

Atomic number

is the number of protons

Mass number

is the number of protons & neutrons

Cations

have a positive charge because they lost electron(s)

Anions

have a negative charge because they gained electron(s)

Oxidation (OILRIG)

is loss of electrons and reduction is gain of electrons (higher tier only)

Ionic bonds

are the strong electrostatic forces of attraction between oppositely charged ions

Covalent bonds

are formed when atoms share electron(s)

Metallic bonds

are the strong electrostatic forces of attraction between a lattice of cations and a sea of delocalised electrons

Ionic substances

have a high melting point and only conduct as a liquid

Metallic substances

have a high melting point and always conduct

Simple covalent substances

have a low melting point and never conduct

Giant covalent substances

have a high melting point and only some of them conduct

Sulfate ions

are SO4 2-

Hydroxide ions

are OH-

Nitrate ions

are NO3-

Carbonate ions

are CO3 2-

Hydrogen gas test

lit splint will give a squeaky pop

Carbon dioxide gas test

limewater will turn milky

Oxygen gas test

a glowing splint relights

Chlorine gas test

blue litmus paper is bleached

Filtration

separates a solid from a liquid

Simple distillation

will separate two liquids with very different boiling points

Fractional distillation

will separate a mixture of more liquids

Chromatography

will separate soluble dyes

Rf

= distance dye travelled / distance solvent travelled

Potable water

is safe to drink

Relative formula mass

is the mass number of every atom in a substance added up

1 mole

of a substance is 6.02 x 10^23 of them (higher tier only)

Number of moles

= mass / relative formula mass (higher tier only)

Concentration

= mass or moles / volume

Rate

= 1/time or rate = volume change / time

Electrolysis

uses a direct current to decompose ionic substances

Electrolysis

is needed to reduce the most reactive metals from their ores

Reduction with carbon

is used to reduce the less reactive metals from their ores

Dynamic equilibrium

is when the rate of forward and backward reactions is equal and the overall concentrations of substances do not change

Group 1

get more reactive down the group as it is easier to lose an electron

Group 7

get less reactive down the group as it is harder to gain an electron

Exothermic reactions

release energy and endothermic reactions gain energy

Energy change

= (sum of all bonds in reactants) – (sum of all bonds in products)

Complete combustion

of a fuel produces carbon dioxide and water

Incomplete combustion

takes place when there is insufficient oxygen

Incomplete combustion

produces carbon monoxide and/or carbon

Photosynthesis

reduced the amount of carbon dioxide in the atmosphere and increased the amount of oxygen

make the ions in the right text

Atomic number

is the number of protons

Mass number

is the number of protons & neutrons

Cations

have a positive charge because they lost electron(s)

Anions

have a negative charge because they gained electron(s)

Oxidation (OILRIG)

is loss of electrons and reduction is gain of electrons (higher tier only)

Ionic bonds

are the strong electrostatic forces of attraction between oppositely charged ions

Covalent bonds

are formed when atoms share electron(s)

Metallic bonds

are the strong electrostatic forces of attraction between a lattice of cations and a sea of delocalised electrons

Ionic substances

have a high melting point and only conduct as a liquid

Metallic substances

have a high melting point and always conduct

Simple covalent substances

have a low melting point and never conduct

Giant covalent substances

have a high melting point and only some of them conduct

Sulfate ions

are SO₄²⁻

Hydroxide ions

are OH⁻

Nitrate ions

are NO₃⁻

Carbonate ions

are CO₃²⁻

Hydrogen gas test

lit splint will give a squeaky pop

Carbon dioxide gas test

limewater will turn milky

Oxygen gas test

a glowing splint relights

Chlorine gas test

blue litmus paper is bleached

Filtration

separates a solid from a liquid

Simple distillation

will separate two liquids with very different boiling points

Fractional distillation

will separate a mixture of more liquids

Chromatography

will separate soluble dyes

Rf

= distance dye travelled / distance solvent travelled

Potable water

is safe to drink

Relative formula mass

is the mass number of every atom in a substance added up

1 mole

of a substance is 6.02 x 10²³ of them (higher tier only)

Number of moles

= mass / relative formula mass (higher tier only)

Concentration

= mass or moles / volume

Rate

= 1/time or rate = volume change / time

Electrolysis

uses a direct current to decompose ionic substances

Electrolysis

is needed to reduce the most reactive metals from their ores

Reduction with carbon

is used to reduce the less reactive metals from their ores

Dynamic equilibrium

is when the rate of forward and backward reactions is equal and the overall concentrations of substances do not change

Group 1

get more reactive down the group as it is easier to lose an electron

Group 7

get less reactive down the group as it is harder to gain an electron

Exothermic reactions

release energy and endothermic reactions gain energy

Energy change

= (sum of all bonds in reactants) – (sum of all bonds in products)

Complete combustion

of a fuel produces carbon dioxide and water

Incomplete combustion

takes place when there is insufficient oxygen

Incomplete combustion

produces carbon monoxide and/or carbon

Photosynthesis

reduced the amount of carbon dioxide in the atmosphere and increased the amount of oxygen