quantitative and qualitative chemistry

the number of particles in 1 mole = 6 × 10^23 mol−1

1 tonne = 1000kg = 1,000,000g

• the simplest whole number ratio of atoms of each element present in a compound • can be determined from the % composition of mass of the elements present in the compound • formula: (mass or %mass / Mr) for both elements, then simplify ratio

do Mr of molecular formula / Mr of empirical formula, then multiply empirical formula by answer

24lmol-1

mass of solute (in g) = conc. (in gL-1) x volume (in L)

• as temp increases, solubility of salts increases - as temp increases, solubility of gases decreases

(actual yield / theoretical yield) x 100

• the reaction will not go to completion if it is reversible • some of the product may be lost when it is separated from the reaction mixture • some of the reactants may also react in ways different to the expected reaction

1 litre

-hydrogen burns with a squeaky pop

-oxygen relights a glowing splint

• carbon dioxide turns limewater cloudy - this is due to the insoluble suspension of calcium carbonate (precipitate) formed

• potassium PETER • sodium SMITH • lithium LUCKILY • calcium CAUGHT • magnesium MY • aluminium AUNT • carbon CATHERINE • zinc ZINA • iron IN • tin THE • lead LARDER • hydrogen HIDDEN • copper CAREFULLY • mercury MUNCHING • silver SOME • gold GREEN • platinum PEAS

-litmus (pH) paper turns red then white

• Li – crimson red • Na – yellow-orange • K – lilac • Ca – red-orange • Cu – green

conc = (mass of solute in grams) / (volume of solution in litres)

100ml / 0.1L

• add dilute nitric acid and a few drops of silver nitrate solution to the unknown solution • halide ions will precipitate as silver halides • each silver halide precipitate has a distinctive colour: • silver iodide = yellow • silver bromide = cream • silver chloride = white

• addition of dilute HNO3 / HCl to the unknown solution, followed by a solution of barium nitrate/chloride • a white precipitate indicates the presence of sulfate ions.

-carbonate ions react with an acid to release CO2 gas

If the anions present in a sample is unknown, test in this specific order: 1) carbonate ions 2) sulfate ions 3) halide ions

• thin wire is washed in a little acid, then dipped into the unknown substance • wire is placed in the blue flame of a Bunsen burner lithium: crimson red sodium: yellow-orange potassium: lilac calcium: red-orange copper: green

-copper(II) sulfate solid is white when anhydrous but blue when hydrated