Speed of reaction, QA, Chemical enegetics, Metals (combine chem)

Rateof reaction:A) Measuringmassof reactantsDownwardcurve:- Gradient isat thesteepest at thestart, indicatingthat reactantsarereactingat theirmaximumspeed.- Eventuallybecomelesssteepbecausereactantsarebeingusedupandsothespeedof reactiondecreases.- Eventuallythereactioncurvewill endwitha0gradient that indicatesthecompletionof reactionwheneitherof thereactantsareusedup. B) Measuringchangeinvolumeof gaseousproducts- Reactionisthefastest at thestart of thereactionwhenthereactantsareatthemaximumamount.- Thegradient progressivelygetslesssteepasthereactantsarebeingusedupandreactionslowsdown.- Graphbecomeshorizontal asthereactionstopswhenoneof thereactantsisusedup. Factorsaffectingspeedof reaction:1. Concentrationof thereactants(solutions)2. Pressure(gas)3. Particlesizeof reactants(solid)4. Temperature A) Concentrationof reactants:- Highertheconcentration, thefasterthespeedof reaction.- Increasingconcentration->Increasingnumberof reactantsparticlesperunit volume.- Lessdistancebetweenreactant particlesandhigherfrequencyof collisionsbetweenthem, causingincreaseinrateof reaction.- Steeperthegradient.- If concentrationof alimitingreagent isdoubled, theamount of productformedwill alsodouble.

B) Pressureof gaseousreactants:- Higherthepressure, fasterthereaction.- Increasingpressureof gaseswill decreasethedistancebetweenthereactantparticles, thusincreasingthenumberof reactantsperparticleunit volume.(Sameasconcentration)- Higherfrequencyof effectivecollisionbetweenreactant particles.- Steepergradient at thestart of reaction.- Amount of product formedremainsthesame. C) Particlesizeof solidreactants:- Thesmallerthereactant particles, thefasterrateof reaction.

- Smallerparticles—>Surfaceareaforreactionislarger—>morechancesofeffectivecollisionsbetweenreactant particles.- Amount of product formedremainsthesame. D)Temperature:- Temperaturerises, theparticlesof thereactantsgainmorekineticenergyandmovefaster.- Causesthenumberof particleswithenergyhigherthantheactivationenergytoincrease. (Abletoovercometheactivationenergy)- Increasesthefrequencyof effectivecollisionsbetweenthereactingparticles.Hence, speedof reactionincreases.- Steepergradient at thestart.- Amount of product formedremainsthesame. Qualitativeanalysis:- Cationsareidentifiedusingtwomainalkalinereagents:->Aqueoussodiumhydroxide->Aqueousammonia A) Test forcationsusingaqueoussodiumhydroxide:- Sodiumhydroxidewill dissociateinwatertoformsodiumhydroxideions.->NaOH(aq)—>Na+(aq)+OH-(aq)

- Changes: Precipitationandeffervescent 1 Cationpresent (+) addingafewdrops addinginexcess AluminiumAl 3+ whiteprecipitateisformed. whiteprecipitatedissolvestogiveacolourlesssolution.(Solubleinexcess) ZincZn 2+ whiteprecipitateisformed. whiteprecipitatedissolvestogiveacolourlesssolution.(Solubleinexcess) Ca 2+ whiteprecipitateisformed. whiteprecipitateisinsoluble. Copper(ll),Cu 2+ Light blueprecipitateisformed. light blueprecipitateisinsoluble. Iron(ll),Fe 2+ greenprecipitateisformed. greenprecipitateisinsoluble. Iron(lll),Fe 3+ reddi