Rates of Reaction :: GCSE Chemistry Coursework Investigation

Rates of ReactionWhat is a rate of response?The amount of change of a product or reactant in a given beat.What affects the rate?a) Concentration of reply (more likely to collide as more in same vol.)b) Temperature (increases speed of molecules, more exceed EA)c) come on area (same as concentration)d) Pressure of gasses (same as conc.)e) Catalyst (guide particles to correct orientation + lowers EA)f) Others e.g. light(light = increase in speed of particles)How are rates altered? clashing theoryParticles essential collide with an energy exceeding the EA and they must ca-ca the correct orientation.A reaction rate increased by,- Increasing bang frequency- Increasing average kinetic energy of particles- Lowering activating energy- Giving molecules correct orientationEffect of concentration on raterA = rate of reaction with respect to AE.g. RH+ = rate of reaction with respect to H+(aq)Rate of reaction = K Aa Bb CcUnits of rates of reaction = mol dm-3 s-1Units of concentration = mol dm-3Indices a, b, c etc gild of reaction - what is the effect on therate of doubling the concentrationE.g. H+1 = first order = if conc. is doubled, rate is doubledH+2 = 2nd order = if con. is double, rate is quadrupledH+0 = cryptograph order = if conc. is doubled, rate is unaffectedThe constant, KK = rate constant. This is a constant of proportionalityUnits may vary but must entangle s-1rA = kA1B1mol dm-3 s-1 = k (mol dm-3)(mol dm-3)for mol dm-3 s-1 to = mol dm-3 s-1because k must = dm3 mol-1 s-1because (mol dm-3)(mol dm-3) = mol2 dm-6, so to equal this out,k = dm3 mol-1 s-1Expt. 11.2a the kinetics of the reaction between calcium carbonate andhydrochloric acidCaCO3(s) + 2HCl(aq) CaCl2(aq) + carbon dioxide(g) + H2O(l)Collect gas given off in a syringe.Create a tableTime (s)Volume of CO2 Vt (cm3)(Vfinal - Vt) cm3Then to find the order, find the half - life if time periods areroughly the same between each half - life accordingly it is first order. Ifit is second order the gr aph would increase and not be constant.Methods of following a reactionBy titrationE.g. reaction between tincture of iodine and propane in acid solution.Then on a graph time can be plotted against titre values, in this casea straight line is seen, suggesting the reaction to be zero orderBy colorimetryCan be used when one of the reactants or products behave a colour, theintensity changing during the reaction. The intensity can be followed exploitation a special colorimeter.By DilatometryWhere during the reaction the total volume of the solution changes.