Topic 1 : Stoichiometric Relationships

the dissolving medium (usually water)

the substance that is dissolved

solvent and solute when mixed together intimately so that the solid phase becomes indistinguishable from the liquid phase.

the amount of solute per volume of solution (units mols per dm3 (litre) or grams per litre)

• weighted average of all the masses of the isotopes of an element • the average mass of atoms of the element on a scale in which an atom of C(12) has a mass of exactly 12 units • written as Ar

Moles = mass (g) / Molar Mass (g/mol)

% Atom Economy = (Molar mass of atoms of useful products/ Molar mass of atoms in reactant) x 100%

Moles = molar concentration (mol/dm^3) * volume (dm^3)

salt + hydrogen

salt + water

salt + water + carbon dioxide

Number of moles = volume used(dm^3) x concentration

Volume of gas (dm^3) = moles * 24

6.022 * 10^23

number of molecules = number of moles * Avogadros number

• Relative molecular mass is the sum of the relative atomic masses of all the atoms in the molecular formula • Written as Mr

the mass of a substance per one mole expressed in g mol−1

• pV = nRT 2. nR = p1v1/t1 = p2v2/t2

• The volume of a given amount of gas is inversely proportional to its pressure when temperature is held constant (Boyle’s law) • For a constant volume and amount of air, the pressure and temperature are directly proportional • For constant pressure, volume and time are directly proportional

Theoretical yield is the maximum quantity of product that can be obtained from given quantities of reactants, assuming completion

Limiting reagent/reactant is the reactant that determines the theoretical yield of a product, after the reaction is complete there will be none left

Excess reagent/reactant is the reactant that is not used up by the reaction, after the reaction is complete this substance will still be present

Volume of gas (dm^3) = moles * 22.7