Revision on consumer, r te, thermo and carbon compound
Exp Reactants Products ObservationI2.6 g of zinc and50 cm3of acid P2.0 mol dm-3Zinc chlorideand hydrogengasThetemperatureof the mixtureincreasesII2.6 g of zinc and50 cm3of acid Q2.0 mol dm-3Zinc sulphateand hydrogengasThetemperatureof the mixtureincreasesdata from Exp I and Exp II that were carried out to studythe rate of reaction of zinc with two acids, P and Q.QUESTION 1- RATE OF REACTION
• (i) By choosing eitherExperiment I or Experiment II, statethe name of the acid used.•
• (i) Write the chemical equationfor the reaction of this acid withzinc. [2 marks]
(ii) Draw an energy profile diagram forthe reaction in 10(a)(i). On the energyprofile diagram show the:–Heat of reaction, AH–Activation energy without a catalyst,–Activation energy with a catalyst, EExplain the energy profile diagram.[10 marks]
∆HE- activattion energywithout catalystE’- activattionenergy with catalystenergyEnergy profile diagram of reactionzinc and hydrochloric acid
What is the function of these food additives?a) Colouring agentsb) preservativesc) Anti oxidantsd) Flavouring agentse) Stabilisers andthickenersa) To restore the colour oforiginal foodb) To destroy or prevent growthof micro organisms in foodc) To prevention oxidation offood by aird) To to give or enhance theflavour of foode) To prevent food such as icecream from separating into layersand to thicken soup or gravyQuestion no. 2) consumer
What type of food additives?Colouring agentspreservativesAnti oxidantsFlavouring agentsStabilisers and thickenersa) Benzoic acidb) Pectinc) Saccharind) aspartame) Ascorbic acidFlavouring agentsf) tartrazinef) Sodium nitrite preservatives
What type of food additives?Colouring agentspreservativesAnti oxidantsStabilisers and thickenersa) Azo compoundb) Vitamin Ec) Mono sodium glutamated) agar-agare) GelatinFlavouring agentsf) Sodium benzoateStabilisers and thickenersg) Sulphur dioxide preservatives
What is the function of these traditional medicines?a) limeb) garlicc) gingerd) onionse) Betel leaves-daun sireha) To increase digestive juiceb) Has antibiotic propertyc) To warm the bodyd) To purift bloode) Stop bleeding nose
What is the function of these modern medicines?a) analgesicsb) antibioticsc)Psychotherapeuticmedicinesa) To relieve pain without affectingconsciousnessb) Kill bacteriac) To treatmental illness
a) stimulantsb) Antidepressantc) Antipsychoticdruga) To stimulate mental activityb) To control worry,fear, anxiety, panicc) To treatpsychotic illness orschizophreniac) Psychotherapeutic medicines
What type of modern medicines?analgesicsAnti bioticsa) aspirinb) Penicillinc) streptomycind) Para cetamole) caffeinef) codeineg) barbiturateAnti bioticsanalgesicsstimulantanalgesicsantidepressanth) tranquiliser antidepressant
What is the uses of modern medicines?Fever, prevent heartattackfevera) aspirinb) Penicillinc) streptomycind) Para cetamolf) codeinepneumonia Tuberculosis,dysentryTreat gonorrhea, syphlis,pneumonia, meningitisCough medicine,headache
Soap:RCOO –Na +or R COO –K +Detergent:What is general formula forsoap?and detergent?
What does hard water contains?•Hard water containscalcium ion, Ca2+ormagnesium ion, Mg2+.
Why do soaps form scum withhard water?• Soap reacts with calciumion, Ca2+or magnesium ion,Mg2+in hard water to forminsoluble salt, called scum
Why is soap not effective in hardwater?• Because formation of scumreduce the amount of soapfor cleaning and thus wastageof soap occur.
Why is detergent more effective thansoap in hard water? • Detergent form soluble salt with calcium ion, Ca2+ormagnesium ion, Mg2+in hard water.• Therefore the cleaning power is not affected by hard water.
Below are some additives in detergents.Fill in missing wordsAdditives Functions1 Drying agents( such as sodiumsulphate, sodiumsilicate)to keep thepowder……………….DRY
Additives Functions2 Builders( such asSodiumtriphosphate)……………water.soften
Additives Functions3 Biologicalenzymes( such asamylase,lipase)to digestin dirt or tomodify fabricfeelPROTEIN, FATORCARBOHYDRATE
Additives Functions4 Such assodiumperborateConvertstains into…………………substancescolourless
Additives Functions5 Perfumes Make clothes smell ……………. And cleanfresh
Additives Functions6.Stabilizers( such assilicones)Preventformation of………………foam
Change of one homologous series to another homologous series Question 3) Revision on alcohols, carboxylicacids and ester
AlcoholCarboxylicacidEsterState the general formula for
5) A student obtained the data todetermine heat of precipitation of PbSO4Solution Vol(cm3)Conc(moldm-3)Initial temp(0C)Pb(NO3)2 50 0.5 27.4Na2SO4 50 0.5 27.6Highest temperature : 30.5 0CQuestion 4- thermochemistry
What is meant by heat ofprecipitation?• Heat changed when 1 mole ofprecipitate is formed from itsions in an aqueous solution
E) Construct energy level diagramPb2++ SO42-Energy∆ H = - 50.4 KJ/molPbSO4
f) The experiment is repeated using K2SO4to replaced Na2SO4. Heat of precipitationof PbSO4 remain the same. Explain.• Because the same precipitate is formed,which is PbSO4.• Only Pb 2+ions and SO42-ions react• Na+ions and K+ions do not react
• 6) A student carried out an experimentto determine heat of displacement ofcopper from CuSO4 solution. He addedexcess zinc powder to 50 cm3of 0.2moldm-3CuSO4. The thermo chemicalequation is shown below :Zn + Cu2+Zn2++ Cu∆ H = -80.64 KJ/mol
a) Calculate the change intemperatureMol Copper= mol copper(II) sulphate= (0.2)(50)/1000 = 0.01 mol∆ H = mCϴmol80 640 J = ( 50)(4.2)(ϴ)0.01ϴ = 3.8 ° C
b) Write the ionic equationZn + CuSO4 Cu + ZnSO4Zn + Cu2+ Zn2++ Cu
The experiment is repeated with thefollowing changes. What is the effect inthe change of temperature when :• Concentration of CuSO4 is doubled,without changing the volume :So, change of temp or ϴ is doubled.Because as the concentrationdoubled, the number of particle perunit volume also doubled.
The experiment is repeated with thefollowing changes. What is the effectin the change of temperature when :• volume of CuSO4 is halved, withoutchanging the concentration :So, change of temp or ϴ is remainthe same. Because, the changes involume do not affect the number ofparticles per unit volume
7) State the diff betw heat change and theheat of reactionHEAT CHANGE HEAT OF REACTIONA)OTHERNAMESDepends on name ofreactions :Heatabsorb, heatreleased-Heat of Precipitation-Heat of displacement-Heat of neutralisation-Heat of combustion
7) State the differences between heatchange and heat of reactionHEAT CHANGE HEAT OF REACTIONB) FORMULAUSEDH= mCϴ ∆ H= mCϴmolC)UNITJoule Kilo Joule/ molD) SYMBOLnone ∆ HE) SIGNNo sign Either + forendothermic rex or– for exothermic rex