assessment for learning in al & asl chemistry through tas

Assessment for Learning Assessment for Learning in AL & ASL Chemistry in AL & ASL Chemistry

Through TASThrough TASChan Kam YuenChan Kam Yuen

TWGHs Mrs Wu York Yu Memorial CollegeTWGHs Mrs Wu York Yu Memorial College/ EMB Seconded Teacher 05-06/ EMB Seconded Teacher 05-06

New AL syllabusNew AL syllabus• Starts from year 05-06Starts from year 05-06• No phase equilibriumNo phase equilibrium• Mechanistic base learning in Organic Mechanistic base learning in Organic

ChemistryChemistry• No Chemistry and SocietyNo Chemistry and Society• Add Chemistry in ActionAdd Chemistry in Action

– Drug Chemistry & Green ChemistryDrug Chemistry & Green Chemistry

Resources Book for Sixth-Form Resources Book for Sixth-Form Practical ChemistryPractical Chemistry

TAS HandbookTAS Handbook• 5 main areas of assessment (Form 902)5 main areas of assessment (Form 902)

– (a) Methodical Working(a) Methodical Working– (b) Experimental Technique(b) Experimental Technique– (c) Manual Dexterity(c) Manual Dexterity– (d) Orderliness(d) Orderliness– (e) Skill in Observations(e) Skill in Observations

Assessment in Synthesis Expt.Assessment in Synthesis Expt.• Expt 4: Synthesis of Ferrate(VI) ionsExpt 4: Synthesis of Ferrate(VI) ions• Ferrate(VI) FeOFerrate(VI) FeO442-2- consists of iron in the + consists of iron in the +6 oxidation state. It is an environmental 6 oxidation state. It is an environmental friendly but powerful oxidising and disinfriendly but powerful oxidising and disinfecting agent. It can oxidise harmful orgfecting agent. It can oxidise harmful organic and inorganic species.anic and inorganic species.

Synthesis of Ferrate(VI) ionsSynthesis of Ferrate(VI) ions• Part A: Preparation of FeOPart A: Preparation of FeO44

2-2-

• Part B: Oxidation of organic and Part B: Oxidation of organic and inorganic pollutantsinorganic pollutants

(a) Methodical Working(a) Methodical Working• A pre-written experiment with experimental A pre-written experiment with experimental

procedure (any planning??)procedure (any planning??)• Procedure is carried out in a correct Procedure is carried out in a correct

sequencesequence• Equipment is utilized effectively and Equipment is utilized effectively and

purposefullypurposefully– mortar & pestle and filtration apparatusmortar & pestle and filtration apparatus

• Time available is managed efficiently (at Time available is managed efficiently (at most 1 hour)most 1 hour)

(b) Experimental Technique(b) Experimental Technique• Experimental apparatus are handled corExperimental apparatus are handled correctly.rectly.• Operations (filtration) is carried out corrOperations (filtration) is carried out correctly and efficiently.ectly and efficiently.• Chemicals are handed in a safe manner Chemicals are handed in a safe manner (NaOH pellets, bleaching water).(NaOH pellets, bleaching water).

(c) Manual Dexterity(c) Manual Dexterity• Practical task is executed in a swift, Practical task is executed in a swift,

confident and assured manner confident and assured manner (observe and communicate)(observe and communicate)

• Operation is successfully completed. Operation is successfully completed. (It can be succeed)(It can be succeed)

(d) Orderliness(d) Orderliness• Working area is kept clean and tidy.Working area is kept clean and tidy.• Bench space is fully utilized.Bench space is fully utilized.• Equipment is placed in an organized Equipment is placed in an organized

way.way.(General Impression)(General Impression)

(e) Skill in Observation(e) Skill in Observation• Student’s oral report on their Student’s oral report on their

findings, made simultaneously with findings, made simultaneously with the observation or immediately the observation or immediately following the event, attains a following the event, attains a reasonable standard.reasonable standard.

Part A: Preparation of FeOPart A: Preparation of FeO442-2-

•Add 10 cm3 of bleaching water in a 100-cm3 beaker.– (b) Handle bleach water in a safe manner

•Grind NaOH pellets into powder and add 3 g of it to the beaker with stirring.– (b) Handle NaOH in a safe manner– (b) Mortar & Pestle is handled correctly

• When most of the NaOH powder dissolves and the mixture remains hot, add 5 drops of 0.3 M FeCl3 solution with stirring for a few seconds.– (e) Skill in observation (record immediately?)

•Add 2 g of NaOH powder into the reaction mixture.– (a) (a) Procedure is carried out in a correct sequProcedure is carried out in a correct sequence (miss or mix up with other steps)ence (miss or mix up with other steps)

•Allow the reaction mixture to cool down– (a) (a) Procedure is carried out in a correct sequProcedure is carried out in a correct sequence (without waiting)ence (without waiting)

•Place a small amount of cotton wool into a dropper. Filter the reaction mixture through the dropper with cotton wool.– (a) (a) equipment is utilized effectively and equipment is utilized effectively and

purposefully (dropper enough?)purposefully (dropper enough?)– (b) (b) operations is carried out correctly operations is carried out correctly

and efficientlyand efficiently– (c) (c) operation is successfully completedoperation is successfully completed– (e) (e) skill in observationskill in observation

Some photosSome photos

Part B: Oxidation of organic and inorganic pollutants• Test 1: Add ~2 cm3 of absolute or normal

ethanol to a test tube containing 2 cm3 of the filtrate collected in Part A. Record your observations.

• Test 2: Add a few drops of the filtrate collected in Part A to a test tube containing 2 cm3 of 2 M H2SO4 solution. Record your observations.– (e) Skill in observation

Oxidation of ethanolOxidation of ethanol

ethanol

Oxidation of KIOxidation of KI

Kl l2

Some remarksSome remarks• Fully understand the principles and Fully understand the principles and

sequences of experimentsequences of experiment• Think in detail about each step Think in detail about each step

(requirement and technique)(requirement and technique)• Understand common mistakes of Understand common mistakes of

studentsstudents