Formulae, Equations And Amounts Of Substance Flashcards
atom
The smallest unit of an element that can exist
molecule
The smallest part of an element or a compound which can exist alone under normal conditions.
ion
An atom or group of atoms possessing a negative charge
element
A substance containing just one type of atom
compound
A substance that contains different elements that have been chemically combined
empirical formulae
The simplest ratio showing the different types of atom present in a substance
molecular formulae
The actual numbers of each type of atom in a molecule of the substance
avagadros constant
6.02x10 23 number of particles in one mole of a substance
moles equation
mass/relative atomic mass
moles equation for molecules
mass/molar mass
moles equation for solution
concentration x volume
moles of gas
volume/24
moles of gas at any temperature and pressure equation and units
n = PV / RT n=moles P=pressure in Nm-2 or Pa V= volume in m3 R=gas constant T=temperature in K
degrees Celsius to kelvin
+273
gas constant
8.314 JK-1 mol-1
litmus colour change
blue in alkali
red in acid
methyl orange colour change
yellow in alkali
red in acid
Phenolphthalein colour change
pink in alkali
colourless in acid
percentage error equation
Apparatus uncertainty/Amount being measured x 100
why may the apparatus uncertainty be doubled
eg. using a burette you measure initial and final volume
percentage yield equation
Mass of material produced/Theoretical maximum mass which could be produced x 100
factors effecting error
larger volume less uncertainty
decimal places
percentage atom economy
Molar mass of useful product/Total molar mass of starting materials x 100
no of atoms
avagadros constant x moles
