Edexcel IGCSE Chemistry equations

Equation linking moles, concentration and volume

moles = concentration x volume

Equation linking mass, moles and relative formula mass

moles= mass/ Mr

Percentage yield

(actual yield/theoretical yield) x 100

Relative atomic mass

(atomic mass of isotope 1 x abundance) + (atomic mass of isotope 2 x abundance) / 100

metal + acid -->

salt + hydrogen

metal oxide + acid -->

salt + water

metal hydroxide + acid -->

salt + water

metal carbonate + acid -->

salt + carbon dioxide + water

dicarboxylic acid + diol -->

polyester + water

carboxylic acid + alcohol -->

ester + water

alkane + halogen -->

haloalkane + hydrogen halide (under UV light conditions)

alkene + halogen -->

dihaloalkane

incomplete combustion

hydrocarbon + oxygen → carbon monoxide + water

complete combustion

hydrocarbon + oxygen --> carbon dioxide + water

hydration of ethene

ethene + steam --> ethanol (with phosphoric acid catalyst)

fermentation of glucose

glucose --> ethanol + carbon dioxide (with yeast catalyst)

catalytic cracking

long chain alkane --> short chain alkene + short chain alkane

(300°C, 60-70atm, aluminium oxide + silicon dioxide/silica)

Haber process

N2 + 3H2 --> 2NH3

oxidising ethanol

ethanol + oxygen --> ethanal + water

(oxidising agents: potassium dichromate + sulfuric acid)

rusting

iron + oxygen --> iron oxide

(both oxygen and water need to be present)

coke reacting with oxygen

carbon + oxygen --> carbon dioxide

coke reacting with carbon dioxide

carbon + carbon dioxide --> carbon monoxide

iron oxide + carbon monoxide -->

iron + carbon dioxide

decomposition of limestone

calcium carbonate --> calcium oxide + carbon dioxide

making slag (calcium silicate)

calcium oxide + silicon dioxide --> calcium silicate

reaction at the anode

anion --> element + electron(s)

reaction at the cathode

cation + electron(s) --> element

molar gas volume

24dm3 = 24,000cm3

dm3 --> cm3 = x 1,000