Chemical Reactions & Equations Chapter 1 Student Worksheet

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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.

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Chapter 1 - Chemicals Reactions & Equations Formative Assessment Manual for Teachers

● Attentionofthestudentsshouldbedrawntowardshowtoaddtheacidslowlywiththehelpofadropperwithoutspillinganyacid.

● Thebottomofthetesttubebecomesveryhotifsubstantialamountsofacidandmetalaretaken.Careoughttobetakenwhilehandlingthetesttube.

● Developmentofobservationskillsinlearnersisanimportantexpectationfromteaching/learningofscience.Specialfocusandattentionmaybegiventothisaspect.

● Asthisactivityinvolvesworkingwithacids,theconcentrationoftheacidsshouldnotbemorethan0.01Morevenmoredilute.ApproximatelydilutinglmLofcommerciallyavailableconcentratedacidto1Laqueoussolution.


Assessment Technique: DemonstrationBasedWorksheet

Objectives:


● 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

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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


● 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.

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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

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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.


Assessment Technique: MCQbasedworksheet

Objectives: To enable students to:

● Writeawordandaskeletalchemicalequation.

● Recogniseabalancedchemicalequation.

● Categorisethegivenreactionsas-combination,decomposition,displacement,doubledisplacementorredoxreaction.

● Differentiatebetweenthetermscorrosionandrancidity.

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Task: Individual

Procedure:

ThestudentsmaybegiventhefollowingMCQbasedworksheetaftertheteaching-learningprocessofwholechapter.Thiswouldbeagreathelpindiagnosingthedifficultyareasinthechapter.

Assessment Parameters:Eachofthefollowingquestionsmaybeassessedgivingequalweightageof1marktoeachquestion.


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

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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

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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

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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


● Students must be encouraged to come prepared with the complete chapter ‘ChemicalReactionsandEquations’.

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● 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.


Assessment Technique:BalancedChemicalEquationWorksheet

Objectives:Toenablethestudentsto-

● Writeformulaeofthecompoundsandelementsappearinginachemicalreaction.

● Writeaskeletalequationonthebasisofthegiveninformation.

● Balancethereaction.

Task: Individual

Procedure:

Thestudentsmaybegiventhefollowingworksheetaftertheteaching-learningprocessofwritingabalancedchemicalequationtostrengthentheconcept.

AssessmentParameters:Eachofthefollowingquestionsmaybeassessedgivingequalweightageof2markstoeachquestion,onemarkforskeletalequationandoneforbalancing.


Q. Write balanced chemical equations for the following word equations:

A. Calciumhydroxide+Carbondioxide Calciumcarbonate+Water

Skeletalequation:______________________________________

Balancedequation:______________________________________

B. Zinc+Silvernitrate Zincnitrate+Silver



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C. Aluminium+Copperchloride Aluminiumchloride+Copper



D. Potassiumbromide(aq)+Bariumiodide(aq) Potassiumiodide(aq)+Bariumbromide(s)



E. Zinccarbonate(s) Zincoxide(s)+Carbondioxide(g)




● Studentsmustbeencouragedtorecallandmemoriesthevalanceandsymboltable3.6,giveninclassIX,NCERTsciencetextbookonpage37sothattheymaybeabletowritetheformulaeofanygiveninorganiccompoundbyjustcriss-crossofvalenciesanddonottaketorotememorizationofeachformula.

● Initially some students may find it difficult to balance the equations directly bycounting,theymustbeencouragedtowritealltheelementsandtheirnumberintheskeletalequationonLHSandRHSinatabularform.

● Whilecarryingouttheaboveworksheet,theteachermayalsodrawtheattentionofthestudentstowardscategorizingthereactionsintodifferenttypesstudiedinthisunit.

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Chapter 2 - Acids, Bases and Salts Formative Assessment Manual for Teachers

Acids, Bases and Salts Chapter 2

Assessment Technique:Balancingthechemicalequation


● 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.


Q. Writebalancedchemicalequationsforthefollowingwordequations:

A. Reactionofacid with metal

Calcium+HydrochloricAcid Calciumchloride+Water

Generalequation:_______________________________________


B. Reactionofbase with metal

Zinc+SodiumHydroxide Sodiumzincate+Water



C. Reactionofacid with metal carbonate

Calcium carbonate +Hydrochloric acid Calcium chloride +Carbon-dioxide+Water



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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



E. Reactionofacid with metallic oxides

Magnesiumoxide+Hydrochloricacid MagnesiumChloride+Water




● Studentsmustbeencouragedtorecallandmemorisethevalanceandsymboltable3.6,giveninclassIX,NCERTsciencetextbookonpage37sothattheymaybeabletowritetheformulaeofanygiveninorganiccompoundbyjustcriss-crossofvalenciesanddonottaketorotememorizationofeachformula.

● Initiallysomestudentsmayfinditdifficulttogeneralizethereactions,encouragethembywritingmorereactionsofsimilarreactantsontheboard.

● Whilecarryingouttheaboveworksheettheteachermayalsodrawtheattentionofthestudentstowardscategorizingthereactionsintodifferenttypesstudiedinthepreviousunitof'ChemicalEquationsandReactions'.

● Anextensiontotheaboveworksheetmaybedesignedbytheteacherbyaskingstudentstoformulatetheirownreactionsbytakingreactantsoftheirchoice.

● Anotherextensiontothesamemaybedoneintheformofagamewherestudentsofoneteamwritereactantsontheboardandthemembersoftheotherteamsuggesttheproducts.All thiswill surely take thestudentsawayfromrotememorisationof thereactionsandwillleadtoappreciationofthechemicalreactions.


Assessment Technique: DemonstrationBasedWorksheet

Objectives:


● Identifytheproductsofachemicalreactionbetweenanacidandabase.

● Writethewordequationsfortheobservedchemicalreaction

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● 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

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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?


● 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.

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Assessment Technique:ConceptBasedWorksheet


● Recallthatanacidreactswithabasetoproducesaltandwater.

● Identifytheacidandbasethatwouldcombinetoformthegivensalt.

● Correlatetheacidic,basicorneutralnatureofthesalttothestrengthoftheacidandbasewhichmaybeusedtoobtainthesalt

● Appreciatethatallsaltsarenotneutral.

● Conceptualisetheformationandnatureofasalt.

Task: Individual

Procedure:

Thestudentsmaybegiventhefollowingworksheetofcompletingthetableafter the teaching-learningofreactionbetweenacidandbasetoformsalttostrengthentheconcept.Thisworksheetmaybeusedtointroduceconceptof'salts'intheclass.

Assessment Parameters:Eachofthefollowingquestionsmaybeassessedgivingequalweightageof2markstoeachsalt.


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

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6 Copperchloride

7 Aluminiumchloride

8 Sodium hydrogencarbonate

9 Ammoniumchloride

10 Potassiumsulphate


● 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

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Aceticacid Weak

Oxalicacid Weak

Carbonicacid Weak

Bases Strong/ weak

Sodiumhydroxide Strong

Potassiumhydroxide Strong

Ammoniumhydroxide Weak

Aluminiumhydroxide Weak

Copperhydroxide Weak

Zinchydroxide Weak

● Anotherextensiontothesamemaybedoneintheformofagamewherestudentsofoneteamwritenameofasaltontheboardandthemembersoftheotherteamwriteitsformulaandsuggesttheacid,basethatmaybeusedtoformthatsaltandpredictthenatureofthesalt.Allthiswillsurelytakethestudentsawayfromrotememorisationoftheconcept.


Assessment Technique:MultipleChoiceQuestionsBasedWorksheet


● Recallthatanacidreactswithabasetoproducesaltandwater.

● Recognisetheacidandbasethatwouldcombinetogivethegivensalt.

● CorrelatethepHtoacidic,basicorneutral.

● Correlatethetypeofionsproducedinaqueoussolutiontothetypeofmedium.

● Findrelationbetweencolourofanindicatorandthenatureofthemedium

Task: Individual

Procedure:

ThestudentsmaybegiventhefollowingMCQbasedworksheetaftertheteaching-learningofthecompleteunit‘Acids.BasesandSalts’tostrengthentheconcepts.

Assessment Parameters:Choiceofeachcorrectanswercarries1mark.

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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

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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


● 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.

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● 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.


Assessment Technique:CrosswordPuzzleWorksheet


● Recallvariousproductsthatareformedwhenacidsorbasesreactwithmetals,metalcarbonatesandhydrogen-carbonates,metallicoxidesetc.

● Correlatecommonnames,chemicalnamesandpropertiesofvarioussaltsintheirsyllabus.

● Recallthechangeofcolourforvariousindicatorsonchangeofmedium.

● Conceptualisevariousreactionsshownbyacidsandbases.

Task: Individual

Procedure:

Thestudentsmaybegiventhefollowingworksheetofcompletingthecrosswordpuzzleaftertheteaching-learningofthecompleteunit‘Acids,BasesandSalts’tostrengthentheconcepts.

Assessment Parameters:Eachcorrectsolutionmaybegivenonemark.

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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

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● 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

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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.


Procedure:

Thestudentsmaybegiventhefollowingworksheetaftertheteaching-learningofthechemicalpropertiesofmetalstostrengthentheconcepts.

Assessment Parameters:Eachofthefollowingquestionsmaybeassessedgivingweightageof2markstoeach.


Writebalancedchemicalequationsforthefollowingreactions-

1. Steamispassedoverredhotiron.

2. Aluminiumoxidereactswithsodiumhydroxide.

3. Potassiumoxideisdissolvedinwater.

25

Formative Assessment Manual for Teachers Metals and Non-Metals - Chapter 3

4. Ironisheatedstronglyinoxygen.

5. Calciumreactswithwater.


● 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.


Assessment Technique:DemonstrationBasedWorksheet

Objectives:ToenableStudentsto-

● Drawcorrelationsbetweenobservationsmadeduringdifferentsetsofexperimentstoreachacomprehensiveconclusionaboutthereactivityseriesofmetals.

● Recallreactivityseriesofmetalstopredicttheproductsofareaction.

● Applytheconceptualandexperimentalknowledgeaboutthemetalstotheusesthattheseareputtoindailylife.


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.

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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


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

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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.


● Somestudentsmayfinditdifficulttorealisethatreversereactionisnotfeasible.Thisdoubtmaybeclearedbylettingthestudentsperformtheactivitiytestthemselves.

● This activity-worksheet should be able to help diagnose any difficulties in theunderstandingoftheconceptsofchemicalpropertiesofmetals.

● Somestudentsmightreportnoreactionforthesetswherereactionsareexpectedthismayhappenifmetalsalreadyhaveanoxideorcarbonatelayerontheirsurface.Theteachermayadvicethestudentstocleanthemetalsbyrubbingthemwithapieceofsandpaper.

● Somestudentsmayfinditdifficulttowritethebalancedchemicalequationsforthereactionstakingplace.ItmaybereiteratestheneedtomemorisethevalenciesoftheelementsandpolyatomicionsfromTable3.6onpage37,classIX,NCERT,Sciencebook.

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Assessment Technique:Electrondotstructures&bondingworksheet


● 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


TheatomicnumbersofthreeelementsA,BandCaregivenAnswerthefollowingquestionsonthebasisofthedata:

A=12 B=16 C=6

Ql. Writetheelectronicconfigurationsofallthethreeelements.

Q2. Whichoftheseelementsisametal?

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Q3. Whichelementwillformananionofvalency2?

Q4. Whichelementwillformacationofvalency2?

Q5. Showtheformationofbondby-electrondots.

Q6. Whichtwoelementswillcombinetoformanionicbond?Alsowritetheformula.


● 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


● Recallchemicalpropertiesofmetals.

● Writebalancedchemicalequationsforreactionsofmetals.

● Correlate reactivity of a metal with the conditions under which metal reacts withwater.

30



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


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

Documents

Chemical Reactions & Equations Chapter 1 Student Worksheet