AQA Chemistry 3 Revision cards for C3 4.0 / 5 based on 2 ratings ? ChemistryTesting and analysing substancesGCSEAll boards Created by: SurekkaCreated on: 22-05-11 17:06 Acids and Alkalis Acids When they dissolve into water they form H+ ions. Release H+ ions which are protons Proton Donors Stronger acid will have an increasing concentration of H+ ions and will be completely ionised. Example Sulfuric Acid H2 SO4 Nitric Acid HNO3 Hydrochloric Acid HCl Weak Acids are partially ionised or not fully dissociated. Citric Acid Ethanoic Acid Carbonic Acid Alkalis When they dissolve in water they form OH- ions Accept H+ ions which are protons Proton Acceptors Stronger Alkalis will have an increasing concentration of OH- ions and will be completely ionised. Examples : Potassium Hydroxide KOH Sodium Hydroxide NaOH Weak Alkalis will be partially ionised or not fully dissociated Ammonia Solution 1 of 5 Titration Titration They are used to find out concentrations. They allow you to find teh exact amount of acid needed to neutralise an amount of alkali. The END POINT is the point in the acid and the alkali have neutralised completely. Strong Alkali + Strong Acid = Any indicator Strong Alkali + Weak Acid = Phenophthalein Weak Alkali + Strong Acid = Methyl Orange Measure out 25 cm* of Acid or alkali in a pipette ( used to measure out a fixed volume of solution) and empty it out in a concial flask Put the suitable Indicator in the Flask Put the other reactant (acid/alkali) in the burette ( used to measure the volume of solution added) Drip the liquid from the burette slowly as you are nearing a colour change record the burette volume when the colour change occurs (END POINT) Repeat it three time and get average 2 of 5 Energy Exothermic Reaction - Gives out heat ... X = Exit Temperature increases More bonds made than bonds broken More chemical energy in the reactants than the products as energy is released Burning Neutralisation reaction between Acid and Alkali Reaction between calcium oxide and water Endothermic Reaction - Takes in heat .. En = In More enerygy is in the product than in the reactants as energy has been taken in. Electroylsis Reaction between Ethanoic Acid and Sodium Carbonate Thermal Decomposition of limestone in a blast furnace 3 of 5 Water Water Cycle Evaporation Condesation Precicpitation Solubility the maximum amount of solute that can dissolve in a certain amount of solvent Ionic compounds are soluble but covalent are insoluble to increase solubility in gases .. temp decrease pressure incresae to increase the solubility in liquids temp increase A saturated solution is where a solute can not dissolve even more than it has dissolved now 4 of 5 Hard water permenant will include 5 of 5
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