Mole Concept and Stoichiometry
Relative Masses (no units, 1dp)
Relative Atomic Mass (Ar)
Relative Isotopic Mass
Relative Molecular Mass (Mr)
Relative Formula Mass (Mr)
Definition
RMM of a molecule is the ratio of the average mass of one molecule to 1/12 the mass of an atom of carbon-12
Definition
RAM of an element is the ratio of the average mass of one atom of that element to 1/12 the mass of an atom of carbon-12
Found in the Periodic Table (the mass number)
Definition
RIM of a particular isotope is the ratio of the mass of one atom of that isotope to 1/12 the mass of an atom of carbon-12.
Definition
RFM of an ionic compound is the ratio of the average mass of one formula unit of that compound to 1/12 the mass of an atom of carbon-12
The mole
Definition
A measure for the amount of substance, which is equal to 6.02x10^23 [particles / elementary entities]. (6.02x10^23 is Avogadro's Constant)
One mole of (element/compound) has a mass of exactly (Ar/Mr)g. Eg: 1 mol of Cl has a mass of 35.5g
Calculations
Relationship between Amount, Number of Particles, Mass and Molar Mass
Fig 1 of https://tinyurl.com/ChemIP3
Empirical and Molecular Formulae
Empirical Formula
Molecular Formula
Definition
A formula of a compound that shows the simplest ratio of each type of atoms in a compound
Definition
A formula of a compound that shows the actual number of atoms in a compound
Relationship
Fig of https://tinyurl.com/ChemIP3
Determination
Fig of https://tinyurl.com/ChemIP3
Determination
Fig of https://tinyurl.com/ChemIP3
Stoichiometry of Gases
Avogadro's Law
Law: Equal volumes of all gases contain the same number of particles at the same temperature and pressure.
Molar Volume
The volume occupied by 1 mol of gas
stp: 22.7 dm3mol-1
rtp: 24.0 dm3mol-1
Implied: When 2 gases are measured at same t & p, Mole ratio = Volume Ratio
Stoichiometry of Gases
Fig 2 of https://tinyurl.com/ChemIP3
Limiting Reagent
The one that is completely used up in the reaction.
Percentages
Percentage Composition by Mass: Fig 3 of https://tinyurl.com/ChemIP3
Percentage Yield: Fig 4 of https://tinyurl.com/ChemIP3
Percentage Purity: Fig 5 of https://tinyurl.com/ChemIP3
Concentrations
Determines the amount of products formed
Calculation Approach: Fig 6 of https://tinyurl.com/ChemIP3
Fig 7 of https://tinyurl.com/ChemIP3