Topic 1 : Stoichiometric Relationships Flashcards
Solvent
the dissolving medium (usually water)
Solute
the substance that is dissolved
Solution
solvent and solute when mixed together intimately so that the solid phase becomes indistinguishable from the liquid phase.
Concentration (definiton)
the amount of solute per volume of solution (units mols per dm3 (litre) or grams per litre)
Relative Atomic Mass
- 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
Moles = mass (g) / Molar Mass (g/mol)
% Atom economy
% Atom Economy = (Molar mass of atoms of useful products/ Molar mass of atoms in reactant) x 100%
Molar concentration
Moles = molar concentration (mol/dm^3) * volume (dm^3)
Acids + metal
salt + hydrogen
Acid + bases
salt + water
acids + carbonates
salt + water + carbon dioxide
no of moles (in solutions)
Number of moles = volume used(dm^3) x concentration
Volume formula of gas at RTP
Volume of gas (dm^3) = moles * 24
Avogadros number
6.022 * 10^23
Number of molecules
number of molecules = number of moles * Avogadros number
Relative molecular mass
- Relative molecular mass is the sum of the relative atomic masses of all the atoms in the molecular formula
- Written as Mr
Molar mass
the mass of a substance per one mole expressed in g mol−1
Ideal gas law
- pV = nRT
2. nR = p1v1/t1 = p2v2/t2
Ideal gas law rules
- 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
Theoretical yield is the maximum quantity of product that can be obtained from given quantities of reactants, assuming completion
Limiting reagent
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
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 formula of gas at STP
Volume of gas (dm^3) = moles * 22.7
