# CHEMISTRY F321 - Atoms, Bonds and Groups: 1.1 Moles, Equations and Acids

 Amount of substance The quantity of substance, expressed in a unit called the mole. This measures a number of particles. Avagadro's constant The number of particles in a mole: 6.02 x 1023 What does a mole measure? An amount of substance/particles/molecules/atoms what is the unit for molar mass? gmol-1 Molar mass The mass of one mole of substance (Mr) Empirical formula The lowest whole number ration of atoms of each element in a compound Molecular formula The actual number of atoms of each element in a molecule 4 steps to calculate empirical formula 1. Calculate moles (or mole percentages)2. Calculate the lowest ratio (by dividing by the smallest)3. Make them all whole numbers4. State the formula  How do you determine the molecular formula from the empirical formula? Take the given molar mass and DIVIDE by the empirical formula mass (using your EF)  Find moles, involving mass. Moles = Mass / Mr Find moles, involving gas volume. Moles = Volume / 24 Find moles, involving solution volume and concentration. Moles = Volume x Concentration How can number of moles be deduced from a previously balanced equation? Using ratios What can we use to determine ratio in the formulae of a compound? Its valency Valency can tell us what about the atom... Which group it is in (in the periodic table) The -ate suffix tells us... the ion contains oxygen and is negatively charged Definition of a mole 6.02 x 1023 particles Acid Releases H+ ions in solution. (Proton donor) Formula for hydrochloric acid HCl Formulae for sulphuric acid H2SO4 Formulae for nitric acid HNO3 Base Proton acceptor Alkali A soluble base that releases OH- ions in solution Salt When the H+ ion of an acid is replaced by a metal ion or NH4+ What is OBSERVED when acids react with a metal oxide? Solid disappears What is OBSERVED when an acid reacts with metal carbonates? Solid disappears and bubbles are seen What is OBSERVED when an acid reacts with an alkali? There is NO observable change Anhydrous The compound that remains when the water of crystallisation is removed from a hydrated salt. Hydrated A complex compound which has water molecules incorporated Water of Crystallisation Water molecules which make up part of the crystal structure of a compound (easily removed by heating) List the 4 steps to determine the formula of a hydrated salt 1. Calculate the mass of water (mass of hydrated - mass of anhydrous)2. Calcualte moles of anhydrous and moles of water3. Calculate the mole ratio between the anhydrous and the water4. State the formula of the hydrated salt Authorjpopat ID181321 Card SetCHEMISTRY F321 - Atoms, Bonds and Groups: 1.1 Moles, Equations and Acids Description1.1 Moles, Equations and Acids Updated2012-12-23T14:32:35Z Show Answers