1
Formative Assessment Manual for Teachers Chemicals Reactions & Equations - Chapter 1
Chemical Reactions & Equations Chapter 1
Assessment Technique: Demonstration Based Worksheet
Objectives:
To enable the students to:
● Recogniseachemicalchange
● Differentiatebetweenachemicalandphysicalchange
● Listtheobservationsthathelptoindicateachemicalchange
● Understandthatachemicalreactionleadstoachemicalchange
● Developscientificskillsofobservation,drawingconclusionsandhandlingchemicals
Task: Individual
Procedure
● ActivityNo.1.3givenonpage2ofClassX,NCERTsciencetextbookmaybecarriedoutintheformofademonstration.Studentsmaybeinvolvedinthedemonstration.
Assessment Parameters:The followingquestionsmaybeassessedgivingequalweightageof 1or2markstoeachquestion.
Student Worksheet Time: 10 min
Answer the following questions on the basis of observations made during the demonstration.
Ql. What did you observe happening at the bottom of the test tube in the activityperformed?
Q2. Didyoufeelanychangeinthetemperatureontouchingthebottomofthetesttube?
Q3. Suggest whether the heat is being released or absorbed during the process of theactivity?
Q4. Whatobservationstellusthatadditionofdiluteacidtozincgranulesleadstoachemicalchange?
Q5. Giveexampleofonephysicalandonechemicalchangefromyourdailylife.
Suggested Remediation:
● Extracautionmaybetakeninexplainingprecautionstothestudents.
2
Chapter 1 - Chemicals Reactions & Equations Formative Assessment Manual for Teachers
● Attentionofthestudentsshouldbedrawntowardshowtoaddtheacidslowlywiththehelpofadropperwithoutspillinganyacid.
● Thebottomofthetesttubebecomesveryhotifsubstantialamountsofacidandmetalaretaken.Careoughttobetakenwhilehandlingthetesttube.
● Developmentofobservationskillsinlearnersisanimportantexpectationfromteaching/learningofscience.Specialfocusandattentionmaybegiventothisaspect.
● Asthisactivityinvolvesworkingwithacids,theconcentrationoftheacidsshouldnotbemorethan0.01Morevenmoredilute.ApproximatelydilutinglmLofcommerciallyavailableconcentratedacidto1Laqueoussolution.
Chemical Reactions & Equations Chapter 1
Assessment Technique: DemonstrationBasedWorksheet
Objectives:
To enable the students to:
● Identifythereactantsandproductsofachemicalreaction
● Writethewordequationsfortheobservedchemicalreaction
● Writesymbolsandformulaeforthereactantsandproducts
● Writeaskeletalchemicalequation
● Balancethechemicalequation
● Understandandappreciatetheneedtobalanceachemicalequation
Task: Individual
Procedure:
1. ActivityNo.1.2givenonpage2ofClassX,NCERTsciencetextbookmaybeperformedintheformofademonstration.Studentsmaybeinvolvedinthedemonstration.
2. Theactivitymaybeperformed instep-wisemanner leading thestudents towriteabalancedchemicalequationforthereactionastheclassproceeds.
Assessment Parameters:
Q1. — Q6.Carries1markeach
Q7. — Q8.Carries2markeach
3
Formative Assessment Manual for Teachers Chemicals Reactions & Equations - Chapter 1
Student Worksheet Time:20 minutes
Answer the following questions :
Ql. Write the names of the reactants taking part in the chemical reaction during thedemonstration.
Q2. Writethechemicalformulaeofboththereactants.
Q3. Listtheobservation(s)whichjustifythatachemicalreactionhastakenplace.
Q4. Theproductsformedduringthereactionareleadoxideandpotassiumnitrate.Writeawordequationforthecompletechemicalreactionthathastakenplace.
Q5. Writetheskeletalequationwithchemicalformulaeofreactantsandproducts.
Q6. Fillthefollowingtableonthebasisoftheaboveskeletalchemicalequation:
Element/Ion NumberonLHS NumberonRHS
Pb
NO3–
K
I
Q7. Istheequationbalanced?Ifnot,balanceit.
Q8. Convertthefollowingwordequationtoabalancedchemicalequation:
Magnesium+Oxygen MagnesiumOxide
Suggested Remediation:
● Some students may find it difficult to write the molecular formulae for the givencompound.StudentsmaybeencouragedtomemoriesthesymbolsandvalenciesfromTable3.6onpage37ofClassIX,NCERTsciencetextbook.
● Some students may break the polyatomic ions into their respective elements. Eg: Nitrate = 1 Nitrogen + 3 Oxygen. This will make the task of balancing thechemicalequationcumbersomeforthestudents.Theteachermaygiveexamplesofvarious displacement anddouble displacement reactions involvingpolyatomic ionslikesulphateandphosphatetoemphasisethatpolyatomicionsneednotbebrokenintoelementswhilebalancingadisplacementreaction.
4
Chapter 1 - Chemicals Reactions & Equations Formative Assessment Manual for Teachers
Chemical Reactions & Equations Chapter 1
Assessment Technique:DiagrambasedWorksheet
Objectives:Toenablestudentsto-
● Recogniseadisplacementreaction.
● Understandtheproductsformedduringadisplacementreaction.
● Compare the reactivity of the two elements on the basis of the products of thedisplacementreaction.
Task: Individual Worksheet
Procedure:
Thestudentsmaybegiven the followingworksheetwithfigure1.8givenonpage10ofclassX NCERT textbook, after activity based teaching-learning of displacement reactions and itsaspects.
Assessment Parameters:Eachofthequestionsmaybegivenonemarkeach.
Student Worksheet Time: 10 minutes
Observethediagramgivenbelowcarefullyandanswerthequestionsthatfollow:
(a)Iron,nailsdippedincoppersitiphatesolution
5
Formative Assessment Manual for Teachers Chemicals Reactions & Equations - Chapter 1
Ql. Aftertenminutesofkeepingthesetupasshowninthefigure,thecolouroftheironnailchanges,whatdoesthisindicate?
Q2. Namethetypeofchemicalreactionthattakesplacebetweencoppersulphateandironnail.
Q3. Whichofthetwometalsinvolvedinthegivenprocessismorereactive?
Q4. Whatchangedoyouexpectinthereactionmixtureifacopperwireiskeptimmersedinanironsulphatesolution?
Q5. Writeabalancedchemicalequationforthereaction,betweencoppersulphateandironnail.
Suggested Remediation
● Somestudentsmayfinditdifficulttorecallandcorrelatethediagramtotheactivityperformed in theclass; theymaybeencouraged toperformtheactivity themselvesonceagain.
● Thestudentsmaybeallowedtodescribethechangeincolourandtextureofnailandcolourofsolutionintheirownwordswhilecarryingouttheactivitybeforethissheetisgiventothemsothat,itdoesn’tbecomearotelearningexercise.
● Somestudentsmaynotbeabletocorrelatethatthereversereactionisnotpossibleasironismorereactivethancopper, teachermayletthestudentsperformthisactivityingroupstoappreciatethatamorereactiveelementdisplacesalessreactiveoneinadisplacementreaction.
● Somemoreeasilyavailablesetsofmetalandmetalsaltsolutions,likezincsulphateandmagnesium,copperandsilvernitrateetc.shouldbegiventothestudentstohelpthemunderstandtheconceptofdisplacementreactionscompletely.
Chemical Reactions & Equations Chapter 1
Assessment Technique: MCQbasedworksheet
Objectives: To enable students to:
● Writeawordandaskeletalchemicalequation.
● Recogniseabalancedchemicalequation.
● Categorisethegivenreactionsas-combination,decomposition,displacement,doubledisplacementorredoxreaction.
● Differentiatebetweenthetermscorrosionandrancidity.
6
Chapter 1 - Chemicals Reactions & Equations Formative Assessment Manual for Teachers
Task: Individual
Procedure:
ThestudentsmaybegiventhefollowingMCQbasedworksheetaftertheteaching-learningprocessofwholechapter.Thiswouldbeagreathelpindiagnosingthedifficultyareasinthechapter.
Assessment Parameters:Eachofthefollowingquestionsmaybeassessedgivingequalweightageof1marktoeachquestion.
Student Worksheet Time: 30 minutes
Thereare15multiplechoicequestions,onlyoneoftheoptionsineveryquestioniscorrect.Choosethecorrectoption.
Q1. Thegivenequationrepresentsthereactionofsodiummetalwithwater.
Sodium+Water Sodiumhydroxide+Hydrogen
Whichofthefollowingchemicalequationsrepresentsacompletebalancedchemicalequationforthegivenwordequation?
A. 2Na(s)+H2O 2NaOH(aq)+H2(g)
B. Na(s)+2H2O NaOH(aq)+2H2(g)
C. 2Na(s)+2H3O 2NaOH(aq)+2H2(g)
D. 2Na(s)+2H2O 2NaOH(aq)+H2(g)
Q2. Identify the chemical equationwhich represents a complete balanced equation forthereactionofbariumchloridewithsodiumsulphatetoproducebariumsulphateandsodiumchloride.
A. BaCl2(aq)+Na2SO4 (aq) BaSO4(s)+2NaCl(aq)
B. BaCl2(aq)+Na2SO4 (aq) 2BaSO4(s)+2NaCl(aq)
C. 2BaCl2(aq)+Na2SO4 (aq) 2BaSO4(s)+NaCl(aq)
D. BaCl2(aq) +Na2SO4 (aq) BaSO4(s)+NaCl(aq)
Q3. Ferricoxidereactswithaluminumtoproducealuminumoxideandiron.Thebalancedchemicalequationforthegivenreactionis
Fe2O3 + 2Al Al2O3 + 2Fe FerricoxideAluminum Aluminumoxide Iron
Whichofthefollowingsubstancesisoxidizedinthegivenreaction?
A. Al2O3 B. Fe2O3 C. A1 D. Fe
7
Formative Assessment Manual for Teachers Chemicals Reactions & Equations - Chapter 1
Q4. Whitesilverchloridechangestogreyinsunlightbecauseoftheformationofsilvermetal alongwith the evolutionof chlorinegas. Identify the chemical equation thatgivesacorrectrepresentationoftheprocess.
A. 2AgCl 2Ag+Cl2 B. AgCl Ag+Cl2
C. 2Ag+Cl2 2AgCl D. Ag+Cl2 2AgCl
Q5. Whencopperoxideistreatedwithhydrogengascopperisproducedalongwithwater.Thebalancedchemicalequationforthegivenreactionis
CuO+H2 Cu+H2O
Whichsubstanceisoxidizedinthegivenreaction?
A. H2 B. Cu C. H2O D. CuO
Q6. ThebalancedchemicalequationforthereactionofnitrogenwithhydrogentoproduceAmmoniagasis-
A. N2(g)+H2(g) 2NH3(g) B. 2N2(g)+H2(g) 2NH3(g)
C. N2(g)+3H2(g) 2NH3(g) D. 2N2(g)+H2(g) 2NH3(g)
Q7. Identifythechemicalequationthatcorrectlyrepresentsproductionofmagnesiumnitridebyburningmagnesiummetalinapurenitrogenatmospherefromthefollowing–
A. Mg3N2(s) Mg(g)+N2(g) B. Mg+N2 Mg3N2
C. 3Mg(g)N2(g) Mg3N2(g) D. Mg3N2 3Mg+N2
Q8. Whichofthefollowingreactionsrepresentsacombinationreaction?
A. CaO(s)+H2O(g) Ca(OH)2(aq)
B. CaCO3(s) CaO(s) + CO2(g)
C. Zn+CuSO4(aq) ZnSO4(aq) + Cu(s)
D. 2FeSO4(s) Fe2O3(s)+SO2(g) + SO3(g)
Q9. Completethefollowingstatementbychoosingcorrecttypeofreactionforxandy.
Statement 1:Theheatingofleadnitrateisanexampleof'x'reaction
Statement 2:Theburningofmagnesiumisanexampleof'y'reaction.”
A. x y
combination decomposition
B. x y
decomposition combination
8
Chapter 1 - Chemicals Reactions & Equations Formative Assessment Manual for Teachers
C. x y
combination deplacement
D. x y
deplacement decomposition
Q10.Whichofthefollowingreactionsrepresentsadoubledisplacementreaction?
A. BaCl2(aq)+Na2SO4(aq) BaSO4(s)+2NaCl(aq)
B. 2FeSO4(s) Fe2O3(s)+SO2(g) + SO3(g)
C. 2Pb(NO3)2(g) 2PbO(s)+4NO2(g) + O2(g)
D. Zn(s)+2AgNO3(aq) Zn(NO3)2(aq)+2Ag(s)
Q11. Completethefollowingstatementbychoosingcorrectoptionsforx and y.“Duringtheprocessofrespiration,glucosecombineswithoxygeninthecellsofourbodyand‘x’ alargeamountofenergy.Hence,respirationisan‘y’process.”
A. x y
releases endothermic
B. x y
absorbes endothermic
C. x y
releases exothermic
D. x y
absorbes exothermic
Q12.Thereaction: Fe2O3(s) + 2Al(s) Al2O3(s) + 2Fe(s) Ferricoxide Aluminium Aluminiumoxide Iron isanexampleofa–
A. combinationreaction B. doubledisplacementreaction
C. decompositionreaction D. displacementreaction
9
Formative Assessment Manual for Teachers Chemicals Reactions & Equations - Chapter 1
Q13.Complete the following statement by substituting x and y with correct options“Corrosion and rancidity are the result of ‘x’ reaction of iron articles and oils/fatsrespectively.Galvanization isdone topreventcorrosionof ironarticlesand ‘y’ areusedtopreventrancidityofoilsorfats.”
A. x y
displacement oxidants
B. x y
oxidation anti-oxidants
C. x y
displacement anti-oxidants
D. x y
oxidation anti-oxidants
Q14.Whichofthefollowingstatementsaboutthereactionbelowisincorrect?
2PbO(s) + C(s) 2Pb(s) + CO2(g)
(i) Leadisgettingreduced (ii) Carbondioxideisgettingoxidized
(iii) Carbonisgettingoxidized (iv) Leadoxideisgettingreduced
A. (i)and(ii) B. (iii)and(iv)
C. (i),(ii)and(iii) D. all
Q15.Whathappenswhendilutehydrochloricacidisaddedtoironfillings?
A. Hydrogengasandironchlorideareproduced
B. Chlorinegasandhydroxideareproduced
C. heatisabsorbed,i.e.testtubebecomescold.
D. Ironsaltandwaterareproduced
Suggested Remediation:
● Students must be encouraged to come prepared with the complete chapter ‘ChemicalReactionsandEquations’.
10
Chapter 1 - Chemicals Reactions & Equations Formative Assessment Manual for Teachers
● Thisworksheetwill give a comprehensive overview of the students understandingofconceptsdealtwith in thechapter.Afteradministrationof theassessment tool,adiagnosisofthedifficultyareasmustbedoneandtheconceptsinwhichstudentshavefacedproblemsmustbere-taught.
● Beforecarryingout theaboveworksheet, theteachermaytakearevisionclassanddraw the attention of the students towards categorizing the reactions into differenttypesstudiedinthischapter.
Chemical Reactions & Equations Chapter 1
Assessment Technique:BalancedChemicalEquationWorksheet
Objectives:Toenablethestudentsto-
● Writeformulaeofthecompoundsandelementsappearinginachemicalreaction.
● Writeaskeletalequationonthebasisofthegiveninformation.
● Balancethereaction.
Task: Individual
Procedure:
Thestudentsmaybegiventhefollowingworksheetaftertheteaching-learningprocessofwritingabalancedchemicalequationtostrengthentheconcept.
AssessmentParameters:Eachofthefollowingquestionsmaybeassessedgivingequalweightageof2markstoeachquestion,onemarkforskeletalequationandoneforbalancing.
Student Worksheet Time: 20 minutes
Q. Write balanced chemical equations for the following word equations:
A. Calciumhydroxide+Carbondioxide Calciumcarbonate+Water
Skeletalequation:______________________________________
Balancedequation:______________________________________
B. Zinc+Silvernitrate Zincnitrate+Silver
Skeletalequation:______________________________________
Balancedequation:______________________________________
11
Formative Assessment Manual for Teachers Chemicals Reactions & Equations - Chapter 1
C. Aluminium+Copperchloride Aluminiumchloride+Copper
Skeletalequation:______________________________________
Balancedequation:______________________________________
D. Potassiumbromide(aq)+Bariumiodide(aq) Potassiumiodide(aq)+Bariumbromide(s)
Skeletalequation:______________________________________
Balancedequation:______________________________________
E. Zinccarbonate(s) Zincoxide(s)+Carbondioxide(g)
Skeletalequation:______________________________________
Balancedequation:______________________________________
Suggested Remediation
● Studentsmustbeencouragedtorecallandmemoriesthevalanceandsymboltable3.6,giveninclassIX,NCERTsciencetextbookonpage37sothattheymaybeabletowritetheformulaeofanygiveninorganiccompoundbyjustcriss-crossofvalenciesanddonottaketorotememorizationofeachformula.
● Initially some students may find it difficult to balance the equations directly bycounting,theymustbeencouragedtowritealltheelementsandtheirnumberintheskeletalequationonLHSandRHSinatabularform.
● Whilecarryingouttheaboveworksheet,theteachermayalsodrawtheattentionofthestudentstowardscategorizingthereactionsintodifferenttypesstudiedinthisunit.
12
Chapter 2 - Acids, Bases and Salts Formative Assessment Manual for Teachers
Acids, Bases and Salts Chapter 2
Assessment Technique:Balancingthechemicalequation
Objectives:Toenablestudentsto-
● Write balanced chemical equations for reactions of acids and bases with metals,carbonatesandhydrogen-carbonates,metallicoxidesetc.
● Appreciate that thegeneralchemicalequations for the reactionsofanyacidoranybasesaresame.
● Conceptualisevariousreactionsshownbyacidsandbases.
Task: Individual
Procedure:
Thestudentsmaybegiventhefollowingworksheetofwritingbalancedchemicalequationsaftertheteaching-learningofvariousreactionsofacidsandbasestostrengthentheconcept.
AssessmentParameters:Eachofthefollowingquestionsmaybeassessedgivingequalweightageof2markstoeachquestion.0.5markforgeneralequationand1.5forbalancedequation.
Student Worksheet Time: 20 minutes
Q. Writebalancedchemicalequationsforthefollowingwordequations:
A. Reactionofacid with metal
Calcium+HydrochloricAcid Calciumchloride+Water
Generalequation:_______________________________________
Balancedequation:______________________________________
B. Reactionofbase with metal
Zinc+SodiumHydroxide Sodiumzincate+Water
Generalequation:_______________________________________
Balancedequation:______________________________________
C. Reactionofacid with metal carbonate
Calcium carbonate +Hydrochloric acid Calcium chloride +Carbon-dioxide+Water
Generalequation:_______________________________________
Balancedequation:______________________________________
13
Formative Assessment Manual for Teachers Acids, Bases and Salts - Chapter 2
D. Reactionofacid with metal hydrogen carbonate
Sodium hydrogen carbonate + hydrochloric acid Sodium chloride +Carbondioxide+Water
Generalequation:_______________________________________
Balancedequation:______________________________________
E. Reactionofacid with metallic oxides
Magnesiumoxide+Hydrochloricacid MagnesiumChloride+Water
Generalequation:_______________________________________
Balancedequation:______________________________________
Suggested Remediation
● Studentsmustbeencouragedtorecallandmemorisethevalanceandsymboltable3.6,giveninclassIX,NCERTsciencetextbookonpage37sothattheymaybeabletowritetheformulaeofanygiveninorganiccompoundbyjustcriss-crossofvalenciesanddonottaketorotememorizationofeachformula.
● Initiallysomestudentsmayfinditdifficulttogeneralizethereactions,encouragethembywritingmorereactionsofsimilarreactantsontheboard.
● Whilecarryingouttheaboveworksheettheteachermayalsodrawtheattentionofthestudentstowardscategorizingthereactionsintodifferenttypesstudiedinthepreviousunitof'ChemicalEquationsandReactions'.
● Anextensiontotheaboveworksheetmaybedesignedbytheteacherbyaskingstudentstoformulatetheirownreactionsbytakingreactantsoftheirchoice.
● Anotherextensiontothesamemaybedoneintheformofagamewherestudentsofoneteamwritereactantsontheboardandthemembersoftheotherteamsuggesttheproducts.All thiswill surely take thestudentsawayfromrotememorisationof thereactionsandwillleadtoappreciationofthechemicalreactions.
Acids, Bases and Salts Chapter 2
Assessment Technique: DemonstrationBasedWorksheet
Objectives:
To enable the students to:
● Identifytheproductsofachemicalreactionbetweenanacidandabase.
● Writethewordequationsfortheobservedchemicalreaction
14
Chapter 2 - Acids, Bases and Salts Formative Assessment Manual for Teachers
● Writesymbolsandformulaeforthereactantsandproducts
● Balancethechemicalequationfortheobservedreaction.
● Deriveageneralequationforneutralizationreactions.
● Understand and appreciate the functionof an indicator to indicate completionof aneutralisationreaction.
Task: Individual
Procedure:
1. Activity No.2.6 given on page 21 of Class X, NCERT science textbook may beperformed in the formof a demonstrationwith the following suggestedvariations.Studentsmaybeinvolvedinthedemonstration.
2. TheteachermayalsobringabouttheconceptofconcentrationofanacidbycarryingouttheactivityinfourtesttubesmarkedA,B,CandDcontainingvaryingstrengths/concentrationsofbase(NaOH).
3. ThepHofall the fourNaOHsolutions shouldbe foundwith thehelpofuniversalindicatorandrecordedbythestudents.Inthetableprovided.
4. Theconcentrationoftheacid(HCl)usedforneutralisationistobekeptconstant.ThepHofacidmaybefoundandrecorded.
5. Theteachermayagainreiteratethe-choice,useandneedofindicatorinthisactivity.
6. Letthestudentscountthenumberofdropsofacidrequiredtochangethecolourofthesolutionandneutralizethebase.
Assessment Parameters:EachofthequestionsthatfollowmaybegivenonemarkeachandQlmaybegivenaweightageof4markstototalupto10marks.
Student Worksheet Time:20 minutes
Answer the following questions one by one as the chemical reaction demonstrated in the class is taken forward:
Ql. Complete the following table according to the observations made during thedemonstrationoftheactivity.
Test tubeno.
pHofthebase
Colourshownbyphenolphthalein
indicator
Numberofdropsofacidrequiredforcompleteneutralisation.
pHofacid=1234
15
Formative Assessment Manual for Teachers Acids, Bases and Salts - Chapter 2
Q2. Write the names of the reactants taking part in the chemical exaction during thedemonstration.
Q3. Listtheobservation(s)whichjustifythatachemicalreactionhastakenplace.
Q4. Writeawordequationandabalancedchemicalequationforthecompletechemicalreactionthathastakenplace.
Q5. Writeageneralisedequationforaneutralisationreaction.
Q6. Whichofthefourtesttubescontainshigherconcentrationofthebase?
Q7. DoespHofasolutionchangewithdilution?
Suggested Remediation:
● The above activity if performedwith patience involving the studentswill prove anexcellenttoolforremovingmisconceptionsaboutstrengthandconcentrationofanacidandbase.Thesameactivitymaythenbeperformedbychoosingthesetofaweakbasesodiumcarbonateandstrongacid-HCIorthesetofaweakacidoxalicacidandstrongbaseNaOH.
● Some students may find it difficult to write the chemical reaction involved and ageneralised chemical equation. Such studentsmay be encouraged tomemories thesymbolsandvalenciesfromTable3.6onpage37ofClassIX.NCERTsciencetextbookandrevisewritingandbalancingofchemicalequations.
● Somestudentsmayfinditdifficulttodifferentiatebetweentheterms-astrongacid/base and a concentrated acid/ base.Theymayuse the two terms inter changeably,throughthisactivityteachermayclarifythisdoubt.
● Extracautionmaybetakeninexplainingprecautionstothestudents. Attentionofthestudentsshouldbedrawntowardshowtoaddtheacidslowlywiththe
helpofadropperwithoutspillinganyacid.
● Developmentofobservationskillsinlearnersisanimportantexpectationfromteaching/learningofscience.Specialfocusandattentionmaybegiventothisaspect.
● Asthisactivityinvolvesworkingwithacidandbase,theconcentrationoftheacidsshouldnotbemorethan0.01Morevenmoredilute.Approximatelydiluting1mLofcommerciallyavailableconcentratedacidto1Laqueoussolution.
● 0.4gofNaOHpalletsmaybedissolved inwater tomakeasolutionof1L togeta0.01MNaOHsolution.SameNaOHsolutionmaybedilutedfurther inpresenceofstudentstogetfoursolutionsofvaryingconcentrations.
16
Chapter 2 - Acids, Bases and Salts Formative Assessment Manual for Teachers
Acids, Bases and Salts Chapter 2
Assessment Technique:ConceptBasedWorksheet
Objectives:Toenablethestudentsto-
● Recallthatanacidreactswithabasetoproducesaltandwater.
● Identifytheacidandbasethatwouldcombinetoformthegivensalt.
● Correlatetheacidic,basicorneutralnatureofthesalttothestrengthoftheacidandbasewhichmaybeusedtoobtainthesalt
● Appreciatethatallsaltsarenotneutral.
● Conceptualisetheformationandnatureofasalt.
Task: Individual
Procedure:
Thestudentsmaybegiventhefollowingworksheetofcompletingthetableafter the teaching-learningofreactionbetweenacidandbasetoformsalttostrengthentheconcept.Thisworksheetmaybeusedtointroduceconceptof'salts'intheclass.
Assessment Parameters:Eachofthefollowingquestionsmaybeassessedgivingequalweightageof2markstoeachsalt.
Student Worksheet Time: 30 minutes
Q. Completethefollowingtablewiththeacidsandbareusedtoformaparticularsalt.Alsogivetheideawhethertheacid/baseisstingorweakandnatureofthesalt.Firstoneisbeingdoneforyou.
S. No.
Salt Acidused
Strong/weak(S/W)
Baseused
Strong/weak(S/W)
Predictednatureofthesalt-acidic,basicorneutral
1 Sodiumchloride HCl (S) NaOH (S) Neutral
2 Potassiumnitrate
3 Zincsulphate
4 Sodiumacetate
5 Potassiumcarbonate
17
Formative Assessment Manual for Teachers Acids, Bases and Salts - Chapter 2
6 Copperchloride
7 Aluminiumchloride
8 Sodium hydrogencarbonate
9 Ammoniumchloride
10 Potassiumsulphate
Suggested Remediation
● Studentsmustbeencouragedtorecallandmemorisethevalanceandsymboltable3.6,giveninclassIX,NCERTsciencetextbookonpage37sothattheymaybeabletowritetheformulaeofanygiveninorganiccompoundbyjustcriss-crossofvalenciesanddonottaketorotememorizationofeachformula.
● Initiallysomestudentsmayfinditdifficulttoidentifytheacidandbaseusedtomakethesalt,encouragethembytellingthemtowritereactionsofformationofsalts.
● Studentsmaybetoldthatasaltofa-
weak acid + weak base = almost neutral strong acid + strong base = neutral weak acid + strong base = basic strong acid + weak base = acidic
● Whilecarryingouttheaboveworksheettheteachermayalsodrawtheattentionofthestudentstowardsacid,baseindicators.
● Thepredictionsmadebythestudentsmaybecheckedwiththehelpoflitmuspaperorsolutionsoastostrengthentheirunderstanding.
● Anextensiontotheaboveworksheetmaybedesignedbytheteacherbyaskingstudentstoformulatetheirownsaltsbytakingacidsandbasesoftheirchoice.
● A list of acids and baseswith categories as strong andweakmay be given to thestudentsadayinadvancebeforeadministeringthisworksheet.Alistisgiventohelp.
Acids Strong/ weak
Hydrochloricacid Strong
Sulphuricacid Strong
Nitricacid Strong
Phosphoricacid Strong
18
Chapter 2 - Acids, Bases and Salts Formative Assessment Manual for Teachers
Aceticacid Weak
Oxalicacid Weak
Carbonicacid Weak
Bases Strong/ weak
Sodiumhydroxide Strong
Potassiumhydroxide Strong
Ammoniumhydroxide Weak
Aluminiumhydroxide Weak
Copperhydroxide Weak
Zinchydroxide Weak
● Anotherextensiontothesamemaybedoneintheformofagamewherestudentsofoneteamwritenameofasaltontheboardandthemembersoftheotherteamwriteitsformulaandsuggesttheacid,basethatmaybeusedtoformthatsaltandpredictthenatureofthesalt.Allthiswillsurelytakethestudentsawayfromrotememorisationoftheconcept.
Acids, Bases and Salts Chapter 2
Assessment Technique:MultipleChoiceQuestionsBasedWorksheet
Objectives:Toenablethestudentsto-
● Recallthatanacidreactswithabasetoproducesaltandwater.
● Recognisetheacidandbasethatwouldcombinetogivethegivensalt.
● CorrelatethepHtoacidic,basicorneutral.
● Correlatethetypeofionsproducedinaqueoussolutiontothetypeofmedium.
● Findrelationbetweencolourofanindicatorandthenatureofthemedium
Task: Individual
Procedure:
ThestudentsmaybegiventhefollowingMCQbasedworksheetaftertheteaching-learningofthecompleteunit‘Acids.BasesandSalts’tostrengthentheconcepts.
Assessment Parameters:Choiceofeachcorrectanswercarries1mark.
19
Formative Assessment Manual for Teachers Acids, Bases and Salts - Chapter 2
Student Worksheet Time: 20 minutes
Choose the correct option for the following questions from the four choices given. Each question has only one correct answer.
Q1. Anelementcommontoallacidsis
A. Chlorine B. Nitrogen
C. Oxygen D. Hydrogen
Q2. Basesonionisationrelease
A. hydrogenions B. sodiumions
C. chlorideions D. hydroxideions
Q3. lngeneral,salts A. areioniccompounds B. containhydrogenions C. containhydroxideions D. turnlitmusred
Q4. Whenaqueoussolutionsofanacidandbasearemixed A. noreactionoccurs B. anewacidandanewbase-areformed C. asaltandwaterisformed D. anacidandasaltisformed
Q5. Whenmagnesiumandhydrochloricacidreact,theyproduce A. Oxygenandmagnesiumchloride B. Chlorineandmagnesiumoxide C. Hydrogenandmagnesiumchloride D. Hydrogenandmagnesiumoxide
Q6. WhenHCI(aq)isexactlyneutralisedbyNaOH(aq),thehydrogenionconcentrationintheresultingmixtureis
A. alwayslessthantheconcentrationofthehydroxideions B. alwaysgreaterthantheconcentrationofthehydroxideions
C. alwaysequaltotheconcentrationofthehydroxideions
D. sometimesgreaterandsometimeslessthantheconcentrationofthehydroxideions
Q7. Acommonsubstancethatcontainsaceticacidis
A. Vinegar B. Ammoniawater
C. Saladoil D. Soap
20
Chapter 2 - Acids, Bases and Salts Formative Assessment Manual for Teachers
Q8. Abaseusedinthemanufactureofsoapis
A. Calciumhydroxide B. Sodiumhydroxide
C. Ammoniumhydroxide D. Zinchydroxide
Q9. Whichofthefollowingsolutionwillturnphenolphthaleinpink?
A. HCl(aq) B. CO2(aq)
C. KOH(aq) D. CH3OH(aq)
Q10.Fruitjuices,suchasorangejuice,contain:
A. BoricAcid B. CitricAcid
C. SulphuricAcid D. NitricAcid
Q11.Whendissolvedinwater,salts
A. Arenon-electrolytes B. Haveabittertaste
C. Areelectrolytes D. Releasehydrogenions
Q12.Abasecanbepreparedbythereactionbetween
A. Anactivenon-metalandwater
B. Agasandwater
C. Asulphideandwater
D. Anactivemetalandwater
Q13.Ofthefollowing,thepropertythatmostcloselyrelatestoacidsis
A. Abittertaste B. Containsthehydroxideion
C. Sourtaste D. Saltytaste
Q14.Asolutionturnsredlitmustoblue.It’spHislikelytobe:
A. 2 B. 5 C. 7 D. 10
Q15.Whichofthefollowingrepresentsabase?
A. KOH B. KCI C. CH3OH D. CH3COOH
Suggested Remediation:
● Somestudentsmayfinditdifficulttoanswerquestionsbasedonnatureandformationof salts, a separateworksheet only for revising salts conceptmaybe prepared andgiventothem.
● Somestudentsmayfinditdifficulttounderstandthemeaningofanelectrolyte.Theteachermaymakethemrecalltheconceptofelectrolysisofwaterdoneinunit1andcorrelatebygivingexamples.
● The teachermay also build a cross-curricular linkwith chemical effect of electriccurrent.
21
Formative Assessment Manual for Teachers Acids, Bases and Salts - Chapter 2
● Theconceptthatanelectrolytedissociatesintoionsinaqueoussolution;acids,basesandsaltsareelectrolytesmaybegiventothestudents.WithQ1,2,3and11theconceptofstrong/weekelectrolytesandstrong/weakacidandbasemaybestrengthened.
● Some studentsmay find it difficult to correlate that all fruits contain only organicacidsandcompounds.Theymaybeaskedtorecognizeanddifferentiateorganicandinorganiccompounds.
● SomestudentsmaybearthemisconceptionthatallcompoundswithOHintheendarebasicinnatureQ9andQ15willhelpremovethis.
● ThedifficultyinsolvingQ6mayberemovedbyreiteratingtheionicequation-
H++OH H2O
Ifanyoftheionsisinhigherconcentrationinthesolutionitwillmakethesolutionacidicorbasicaccordingly.
Acids, Bases and Salts Chapter 2
Assessment Technique:CrosswordPuzzleWorksheet
Objectives:Toenablestudentsto-
● Recallvariousproductsthatareformedwhenacidsorbasesreactwithmetals,metalcarbonatesandhydrogen-carbonates,metallicoxidesetc.
● Correlatecommonnames,chemicalnamesandpropertiesofvarioussaltsintheirsyllabus.
● Recallthechangeofcolourforvariousindicatorsonchangeofmedium.
● Conceptualisevariousreactionsshownbyacidsandbases.
Task: Individual
Procedure:
Thestudentsmaybegiventhefollowingworksheetofcompletingthecrosswordpuzzleaftertheteaching-learningofthecompleteunit‘Acids,BasesandSalts’tostrengthentheconcepts.
Assessment Parameters:Eachcorrectsolutionmaybegivenonemark.
22
Chapter 2 - Acids, Bases and Salts Formative Assessment Manual for Teachers
Student Worksheet Time: 20 minutes1
2
3
4
5
6 7
8
9
10
11 12
13
14
15
Down1. nameofprocessofelectrolysisofaqueoussodiumchloride(2words)2. Changeincolouroflitmusinbasicmedium(3words)4. chemicalnameofwashingpowder(2words)5. medicineforacidityandindigestion6. commonnameofsodiumhydrogencarbonate(2words)7. Changeincolouroflitmusinacidicmedium(3words)8. Gasreleasedwhenanactivemetalreactswithanacid9. commonnameofcalciumsulphateherruhydrate(3words)12. Acidsandbasesreacttoproducewaterand—
Across1. Gasreleasedwhenametalcarbonatereactswithanacid(2words)3. Thisindicatorgivesreddishpinkcolourinacidicsolution(2words)10. mixtureofsodiumhydrogencarbonateandtartaricacidtomakecakes(2words)11. Cornrnonnameofdilutesolutionofaceticacid13. Thisindicatorgivesmagentapinkcolourinalkalinesolution14. Acidsandbasesreacttogive____________reaction15. PlasterofParisisobtainedbyheating
23
Formative Assessment Manual for Teachers Acids, Bases and Salts - Chapter 2
Suggested Remediation:
● Somestudentsmayfinditdifficulttocorrelatethecommonnameofasalt,acidorabasetoitschemicalnameandformula,acomprehensivetablemaybepreparedwithfourcoloumnsasfollowsandstudentsmaybeaskedtosearchforvariouscompoundsintheirsyllabusandfillthetableastheyproceedtolearnmore.
S.No. ChemicalName
CommonName
ChemicalFormula
Spl.Information/propertyofthecompound
Eg.-l Sodiumhydrogencarbonate
BakingSoda
NaHCO3 Usedtomakecrispypakoras,Bakingpowder...
● Allthereactionsofacidsandbasesmayberecalledandgeneralequationsmaybeputonachartforquickrecall.
● Initiallysomestudentsmayfinditdifficulttostartthecrosswordtheymaybegivenacluetostartwithappropriateanswertothecluetheyaresureof.
● Theymaybetoldgapsbetweentwowordsarenotleftinacrossword.
Solutiontothecrossword
Answer Key1C A R B 0 N D I O X I D E
2R H
3M E T H Y L 0 R A N G E
D 0 5
T R 5A 0
() A 6B B N D
B L A L T I
L K K U A *II U
U 9 P A I E C V M
E L L N T I D C
10B A K I N G P 0 W D E R A
S S R 0 R
T 0 E G B
E D D E 0
11V 1 N K G A R A 12S N N
0 A A
1 1 I
13P H E N 0 L P H T 11 A L E 1 N
A
14N E U T R A L I s A T I 0 N
1
15G Y P S U M
24
Chapter 3 - Metals and Non-Metals Formative Assessment Manual for Teachers
Metals and Non-metals Chapter 3
Assessment Technique:ChemicalEquationBasedWorksheet
Objectives: To enable students to–
● Recallchemicalpropertiesofmetals.
● Writebalancedchemicalequationsforreactionsofmetals.
● Correlate reactivity of a metal with the conditions under which metal reacts withwater.
Task: Individual Worksheet
Procedure:
Thestudentsmaybegiventhefollowingworksheetaftertheteaching-learningofthechemicalpropertiesofmetalstostrengthentheconcepts.
Assessment Parameters:Eachofthefollowingquestionsmaybeassessedgivingweightageof2markstoeach.
Student Worksheet Time: 10 minutes
Writebalancedchemicalequationsforthefollowingreactions-
1. Steamispassedoverredhotiron.
2. Aluminiumoxidereactswithsodiumhydroxide.
3. Potassiumoxideisdissolvedinwater.
25
Formative Assessment Manual for Teachers Metals and Non-Metals - Chapter 3
4. Ironisheatedstronglyinoxygen.
5. Calciumreactswithwater.
Suggested Remediation:
● Some students may find it difficult to remember various reactions. They may beencouraged to tabulate various reactionsofmetals in general formandbe familiarwithallthereactions.
● Revisitingchapter1‘ChemicalReactionsandEquations’mayberequiredforstudentswhofinditdifficulttowritebalancedchemicalreactions.
● Teachermaydrawattentionof the students towards categorising the reactions intovarioustypesstudiedinchapter1.
● Thisworksheetshouldbeabletohelpdiagnoseanydifficultiesintheunderstandingoftheconceptsofchemicalpropertiesofmetals.
Metals and Non-metals Chapter 3
Assessment Technique:DemonstrationBasedWorksheet
Objectives:ToenableStudentsto-
● Drawcorrelationsbetweenobservationsmadeduringdifferentsetsofexperimentstoreachacomprehensiveconclusionaboutthereactivityseriesofmetals.
● Recallreactivityseriesofmetalstopredicttheproductsofareaction.
● Applytheconceptualandexperimentalknowledgeaboutthemetalstotheusesthattheseareputtoindailylife.
Task: Individual Worksheet
Procedure:
1. Activity No.3.12 given on page 44 of Class X, NCERT science textbookmay beperformed in the formof a demonstrationwith the following suggestedvariations.Studentsmaybeinvolvedinthedemonstration.
26
Chapter 3 - Metals and Non-Metals Formative Assessment Manual for Teachers
2. Theactivityofstudyingtheinteractionofmetalssuchasmagnesium,zinc,iron,tin,lead,copper,aluminiumwithsaltsolutionofothermetalstmayalsobecarriedout.Experimentno l1givenonpagenumber51,NCERT,LaboratoryManual,Science,classXmaybefollowedforthis.
3. Thestudentsmayalsotheshownthatgoldandsilverdonotreactwithanyofthesaltsolutions.
Assessment Parameters:Eachofthefollowingquestionsmaybeassessedgivingweightageasfollows,addingtotalto20marks.
Table-1:1marks Table-2:2marks Table-3:2marks
Q2:2marks Q3:2marks Q4:4marks
Q5:2marks Q6:2marks
Student Worksheet Time: 40 minutes
Answer the following questions
Ql. Complete the following tables according to the observations made during thedemonstrationoftheactivity.
Table 1
Metal Colour/appearanceofmetalbeforeputtingintosolution
Zinc
Iron
Copper
Magnesium
Table 2
AqueousSolutionof- Colour/appearanceofsolutionbeforeputtingmetstinto
Zincsulphate
Ironsulphate
Coppersulphate
Magnesiumsulphate
SilverNitrate
27
Formative Assessment Manual for Teachers Metals and Non-Metals - Chapter 3
Table 3: Putacrossincasenoreactionisobservedand
writethecolourchangeincaseareactiontakesplace.
Metal
AqueousSolutionof-
ZincSulphate Magnesiumsulphate
CopperSulphate
Ironsulphate Silvernitrate
Zinc
Iron
Copper
Magnesium
Q2. Listtheobservation(s)whichjustifythatachemicalreactionhastakenplacewhenironmetalfellingispurebutintocophersulphatesolution.
Q3. In the following reactionMandNaremetals.NS is a salt ofmetalM.FollowingreactiontakesplacewhenMisaddedtoaqueoussolutionofNS.
M+NS MS+N Whichofthetwometalsismorereactive?ForthesamemetalsMandN,predictthe
interactionbetweenMPandN,WhereMPisanothersaltofthemetalM.
Q4. Writebalancedchemicalequationsforreactionofmagnesiuminwith(i)ZincSulphate(ii)SilverNitrate
Q5. Wecansafelystorecoppersulphatesolutioninansilvervessel,justifythisstatement.
Q6. Arrangethemetalstakenintheincreasingorderoftheirreactivity.
Suggested Remediation:
● Somestudentsmayfinditdifficulttorealisethatreversereactionisnotfeasible.Thisdoubtmaybeclearedbylettingthestudentsperformtheactivitiytestthemselves.
● This activity-worksheet should be able to help diagnose any difficulties in theunderstandingoftheconceptsofchemicalpropertiesofmetals.
● Somestudentsmightreportnoreactionforthesetswherereactionsareexpectedthismayhappenifmetalsalreadyhaveanoxideorcarbonatelayerontheirsurface.Theteachermayadvicethestudentstocleanthemetalsbyrubbingthemwithapieceofsandpaper.
● Somestudentsmayfinditdifficulttowritethebalancedchemicalequationsforthereactionstakingplace.ItmaybereiteratestheneedtomemorisethevalenciesoftheelementsandpolyatomicionsfromTable3.6onpage37,classIX,NCERT,Sciencebook.
28
Chapter 3 - Metals and Non-Metals Formative Assessment Manual for Teachers
Metals and Non-metals Chapter 3
Assessment Technique:Electrondotstructures&bondingworksheet
Objectives:Toenablethestudentsto-
● Recallwritingofelectronicconfigurationofelements.
● Correlate the electronic configuration to the valence and type of bonds formed forelements.
● Writeelectrondotstructuresofelements.
● Understandandshowformationofioniccompoundsbytransferofelectrons.
Task: Individual
Procedure:
The studentsmay be given the followingworksheet after the teaching-learning experience offormationofcompoundsbetweenmetalsandnon-metals,i.e.formationofionicbonds.
Assessment Parameters:Eachofthefollowingquestionsmaybeassessedgivingweightageasfollows.
Ql. 3marks Q2. 1mark Q3. lmark
Q4. 1mark Q5. 2marks Q6. 2marks
Student Worksheet Time: 10 minutes
TheatomicnumbersofthreeelementsA,BandCaregivenAnswerthefollowingquestionsonthebasisofthedata:
A=12 B=16 C=6
Ql. Writetheelectronicconfigurationsofallthethreeelements.
Q2. Whichoftheseelementsisametal?
29
Formative Assessment Manual for Teachers Metals and Non-Metals - Chapter 3
Q3. Whichelementwillformananionofvalency2?
Q4. Whichelementwillformacationofvalency2?
Q5. Showtheformationofbondby-electrondots.
Q6. Whichtwoelementswillcombinetoformanionicbond?Alsowritetheformula.
Suggested Remediation:
● Somestudentsmayfinditdifficulttowritetheelectronicconfigurationofelements,theymaybeguidedtorevisittheBohr’satomicmodelgiveninchapter‘StructureoftheAtom’,classIX,Science,NCERTbook.
● Some studentsmayfind it difficult tovisualise andunderstand thebond formationthroughelectrontransfer,astheymaybekinaestheticlearners,suchstudentsmaybehelpedbymakingmodelswithbeadstounderstandtheconcept.
● Asanextensionformationofcovalentbondsmaybedealthereafterthestudentshavemasteredtheformationofionicbonds.
● Practiceatrecognisingametalandnon-metalafterlookingattheelectronicconfigurationmayberequired,teachermaytakecaretogiveenoughpracticetothestudents.
Metals and Non-metais Chapter 3
Assessment Technique:BalancedReactionsBasedWorksheet
Objectives:Toenablestudentsto-
● Recallchemicalpropertiesofmetals.
● Writebalancedchemicalequationsforreactionsofmetals.
● Correlate reactivity of a metal with the conditions under which metal reacts withwater.
30
Chapter 3 - Metals and Non-Metals Formative Assessment Manual for Teachers
Task: Individual Worksheet
Procedure:
Thestudentsmaybegiventhefollowingworksheetaftertheteaching-learningoftheextractionofmetalstostrengthentheconcepts.Followinginformationmaybereiteratedandrevisedbeforegivingtheworksheet.
● MetalSulphidesreactwithdiluteacidstoreleaseH2Sgaswhichhasasmellofrotteneggs.
● MetalCarbonatesreactwithdiluteacidstoreleaseCO2gaswhichisanodourlessandcolourlessgasreleasedasbriskeffervescence.
● Zincshowsavalenceofonly+2.
● Ironexistsintwocommonvalencestates+2and+3.
● Copperexistsintwocommonvalencestatesof+1and+2.
● Figure3.10showingaflowchartforthestepsinvolvedintheextractionofmetalsfromoresonpageno.50,NCERTClassXScienceTextbook.
Assessment Parameters:Eachofthefollowingquestionsmaybeassessedgivingweightageasfollows.
Ql. 4 marks Q2. 2 marks Q3. 4 marks
Student Worksheet Time: 10 minutes
Ql. Anoreofmetal‘M’ofmediumreactivityontreatmentwithdilutehydrochloricacidgivesasmellofrottenegg’:Drawaflowcharttodepictvariousstepsinvolvedintheextractionofmetal‘M’fromitsore.
Q2. Anoreon treatmentwithdilutehydrochloricacid releasesbriskeffervescenceofacolourlessandodourlessgas.Identifythetypeoforeandthemethodthatmaybeusedtogettheoxideofmetalfromtheore.
Q3. Followingarethefactsaboutametal‘M’-
● Metal‘M’isextensivelyfoundasitsoreM2O3
● M2O3combineswithmoisturepresentintheairtoformflakybrownsubstance.
● MetalMiscapableofformingtwochlorides-MCl2andMCl3
● MetalMmaybeextractedfromitsoreM2O3bythermitreaction
a. IdentifymetalM,
b. Writethethermitreactionbywhichitmaybeobtained