PAGs

Add base to the acid. As it reacts it will dissolve. When fully reacted no more solid will dissolve. Filter the excess base to leave only the salt solution. Evaporate some of the water to make the solution more concentrated And then allow to evaporate on its own for a longer period of time. The salt will crystallise and pure and solid salt crystals will form

Carry out titrations to find amount of alkali needed to neutralise acid exactly using indicator. Repeat without indicator Transfer neutralised solution to evaporating basin. Heat over bunsen flame to evaporate the water. Don’t heat too strongly as this will cause spitting. Once crystals start to appear, stop heating. Let the mixture cool in basin, then filter. Wash the solid residue with cold distilled water. Transfer the residue to a watch glass + heat in an oven to dry the solid. Make sure temp is lower than melting point of the salt Remove the watch glass and cool in a dessicator, then weigh. Once the solid has dried to a constant mass, stop heating and cool in the dessicator.

A dessicator allows allows substances to dry in a cool, dry atmosphere. This prevents moisture being reabsorbed.

(Accuracy of equipment ÷ Measurement made) x 100 If a measuring cylinder has 1cm³ graduations, the error is ±0.5cm³. This value is the ‘accuracy of the equipment’ Need to multiply % error by however many times the equipment is used to make a measurement

Product may be lost from reaction vessels, especially if there are several stages to the reaction (lost when transfering product) Side reactions occur, creating by-products Impurities in the reactants Changes in temperature + pressure If the reaction is an equilibrium system

(Actual yield / Theoretical yield) x100