TEMA 2: Penerokaan Unsur dalam Alam BAB 6 Elektrokimia ...

ElektrokimiaElectrochemistry

Konsep PENTINGIMPORTANT concepts

6BIDANGPEMBELAJARAN

BA

B

APAKAH ITU ELEKTROKIMIA? WHAT IS ELECTROCHEMISTRY?

Elektrokimia adalah satu cabang kimia fizikal yang mengkaji tentang hubung kait antara elektrik dengan perubahan kimia. Pengetahuan dalam elektrokimia diaplikasikan di dalam industri seperti untuk membuat bateri dan untuk mengekstrak logam daripada bijihnya.Electrochemistry is the branch of physical chemistry that studies the relationship between electricity and its chemical change. Knowledge of electrochemistry is applied in industry such as to make electrical batteries and to extract metals from their ores.

TEMA 2: Penerokaan Unsur dalam Alam

ELEKTROKIMIAELECTROCHEMISTRY

Perubahan tenagaEnergy change

Penghasilan tenaga elektrik daripada pelbagai sumberThe production of electrical energy from various sources

Sel kimiaChemical cell

Sel elektrolitik Electrolytic cell

Struktur sel elektrolitikStructure of electrolytic cell

Proses elektrolisis ke atas sebatian iondalam keadaan pepejal, leburan dan akueusThe process of electrolysis of ionic compounds in solid, molten and aqueous states

Faktor-faktor yang mempengaruhi hasil elektrolisisFactors affecting the products of electrolysis

Aplikasi elektrolisis dalam industri iaitu pengekstrakan, penyaduran dan penulenan Application of electrolysis in industry i.e. extraction, electroplating and purification.

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NOTA BESTARI

Elektrolisis 1. Elektrolisis ialah proses penguraian bahan kimia dalam

larutan akueus atau leburan kepada juzuknya dengan menggunakan arus elektrik.

2. Tenaga elektrik berubah kepada tenaga kimia dalam proses elektrolisis.

3. Semasa proses elektrolisis, kation (ion positif) bergerak ke katod manakala anion (ion negatif) bergerak ke anod.

4. Di katod, kation menerima elektron dan dinyahcas untuk membentuk atom neutral. Di anod, anion membebaskan elektron dan dinyahcas untuk membentuk atom neutral.

5. Faktor yang mempengaruhi hasil elektrolisis adalah kedudukan ion dalam siri elektrokimia, kepekatan elektrolit dan jenis elektrod.

6. Kegunaan elektrolisis dalam industri: (a) Pengekstrakan logam

• Logam yang lebih reaktif daripada karbon diekstrak daripada bijihnya dengan elektrolisis.

(b) Penulenan logam • Logam yang tidak tulen dijadikan anod

manakala logam tulen dijadikan katod. • Elektrolitialahlarutan garam bagi logam itu.

(c) Penyaduran logam • Logam yang digunakan untuk menyadur

dijadikan anod manakala bahan yang ingin disadur dijadikan katod.

• Elektrolit ialah larutan garam bagi logam yang diguna sebagai anod.

• Tujuan penyaduran logam adalah untuk mengelakkan logam daripada terkakis (berkarat) dan menjadikan logam kelihatan lebih menarik.

7. Syarat-syarat penyaduran logam secara kekal, sekata dan cantik termasuk: (a) logam yang hendak disadur perlu dibersihkan

(dengan kertas pasir) terlebih dahulu.(b) arus elektrik yang kecil dialirkan.(c) larutan elektrolit yang cair digunakan(d) tempoh penyaduran adalah lama.(e) logam yang disadur itu perlu dipusing perlahan-

lahan semasa elektrolisis.

Electrolysis 1. Electrolysis is the decomposition of a chemical

substance in an aqueous solution or the molten state to its constituents by using electricity.

2. Electrical energy is changed to chemical energy in electrolysis.

3. During electrolysis, cation (positive ion) moves towards the cathode while anion (negative ion) moves towards the anode.

4. At the cathode, the cations receive electrons and are discharged to form neutral atoms. At the anode, the anions release electrons and are discharged to form neutral atoms.

5. Factors affecting the products of electrolysis are the position of ions in the electrochemical series, the concentration of electrolytes and the type of electrode.

6. The uses of electrolysis in industry include: (a) Extraction of metals

•Metalsthataremore reactive than carbon are extracted from their ores by electrolysis.

(b) Purification of metals •The impure metal is used as the anode while

the pure metal is used as the cathode. • The electrolyte is a solution of a salt of the

metal. (c) Electroplating of metals

• Themetal used for electroplating becomes the anode while the object to be plated becomes the cathode.

• The electrolyte is a solution of a salt of the metal that is used as the anode.

• The aims of electroplating are to prevent the metal from corrosion (rusting) and make the metal looks more attractive.

7. Conditions for high quality metal plating include:(a) the metal to be coated must be cleaned (with

sand paper) before being electroplated.(b) only a low electric current is used.(c) a dilute electrolyte solution is used.(d) the electroplating period is long.(e) the metal being plated should be rotated slowly

during the electrolysis.

Sel Ringkas 1. Sel ringkas terdiri daripada dua logam yang berlainan

yang dicelup ke dalam suatu larutan elektrolit. 2. Perubahan kimia yang berlaku menghasilkan tenaga

elektrik. 3. Pengetahuan tentang prinsip penghasilan tenaga

elektrik daripada tindak balas kimia telah diaplikasikan untuk menghasilkan pelbagai jenis sel kimia.

Simple Voltaic Cells 1. A simple voltaic cell consists of two different metals

that are immersed in an electrolyte. 2. Chemical changes occur to produce electrical energy. 3. Knowledge of the principle of producing electrical

energy from chemical reactions has been applied to produce various types of chemical cells.

Nota Grafik

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Standard Kandungan6.1 Sel Elektrolitik Tarikh:

AKTIVITIPERBINCANGAN Konstruktivisme

PBD6.1 Sel elektrolisisElectrolytic cell

1 Apakah yang dimaksudkan dengan proses elektrolisis? TP2

What is meant by the process of electrolysis?

Proses penguraian sesuatu sebatian dalam keadaan lebur atau akueus kepada

unsur juzuknya apabila arus elektrik mengalir melaluinya.

The process of decomposition of a compound in a molten or aqueous state into its constituent

elements when an electric current flows through it.

2 Lengkapkan ruang tentang sel elektrolisis dan proses elektrolisis. TP1

Complete the spaces about the electrolytic cell and the process of electrolysis.

KatodCathode

AnionAnion

ReostatRheostat

ElektrolitElectrolyte

KationCation

AnodAnode

Bukan elektrolitNon-electrolyte

AmmeterAmmeter

(h) Bukan elektrolit ialah bahan yang tidak boleh mengalirkan arus elektrik.

Non-electrolyte is the substance that cannot conduct electric current.

3 Tandakan ( ✓ ) dalam petak untuk menentukan pergerakan ion yang betul semasa elektrolisis. TP2

Tick ( ✓ ) in the boxes to determine the correct movement of ions during electrolysis. (a) (b)

✓Anion Anion

AnionAnion

KationCation ✓

Kation Cation

(a) Ammeter/Ammeter

•Menyukataruselektrik/Measure the electric current

(d) Reostat/Rheostat •Mengawalpengaliranarus

elektrik/Controls the flow of the electric current

(b) Anod/Anode

•Elektrodpositif Positive electrode

(e) Katod/Cathode

•Elektrodnegatif Negative electrode

(g) Elektrolit/Electrolyte •Larutanatauleburanyangmengalirkanaruselektrik A solution or molten compound that conducts electric current

(f) Kation/Cation •Ionbercaspositif Positive-charged ion

(c) Anion/Anion

•Ionbercasnegatif Negatively-charged

ion

BateriBattery

A

wayarwire

elektrod negatif/katod ( – )negative electrode/cathode ( – )

elektrod positif/anod (+)positive electrode/anode (+)

wayarwire

Buku teks m/s 178 – 192

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Tarikh:

EKSPERIMENBERPANDU Penemuan Inkuiri

PBD6.2 Elektrolisis sebatian ion dalam pelbagai keadaanElectrolysis of ionic compounds in various states

KBATKBAT

Untuk mengkaji proses elektrolisis sebatian ion dalam keadaan pepejal, leburan dan akueus.To study the electrolysis process of ionic compound in solid, molten and aqueous states.

Bolehkah sebatian ion dalam keadaan pepejal, leburan dan akueus mengalami elektrolisis?Can ionic compounds undergo electrolysis in solid, molten and aqueous states?

1 Sebatian ion dalam keadaan leburan dan akueus boleh menjalani proses elektrolisis.

Ionic compounds undergo electrolysis in molten and aqueous states.

2 Sebatian ion dalam keadaan pepejal tidak boleh menjalani proses elektrolisis.

Ionic compounds do not undergo electrolysis in solid state.

(a) yang dimanipulasikan/that is manipulated: Keadaan sebatian ion, iaitu pepejal, leburan atau akueus

State of ionic compounds namely solid, molten or aqueous

(b) yang bergerak balas/that responds: Keadaan mentol/Condition of light bulb

(c) yangdimalarkan/that is kept constant: Jenis elektrod/Type of electrode

Serbukplumbum(II)bromida,larutankuprum(II)sulfat1moldm–3 Lead(II) bromide powder, 1 mol dm–3 copper(II) sulphate solution

Sel elektrolitik, kayu uji, bateri, elektrod karbon, mangkuk pijar, tabung uji, mentol, suis, dawaipenyambungdenganklipbuaya,spatula,alassegitigatanahliat,tungkukakitiga,penunu Bunsen.Electrolytic cell, wooden splinter, batteries, carbon electrodes, crucible, test tube, bulbs, switch, connecting wires with crocodile clips, spatula, pipeclay triangle, tripod stand, Bunsen burner

A. Elektrolisis bagi sebatian ion dalam keadaan pepejal dan leburan Electrolysis of ionic compound in solid and molten states(Demonstrasi guru/Demonstration by the teacher)

Rajah (a)/Diagram (a)

1 Sediakan susunan radas seperti yang ditunjukkan dalam Rajah (a).Set up the apparatus as shown in the Diagram (a).

2 Masukkansedikitserbukplumbum(II)bromidakedalammangkukpijar.Put some lead(II) bromide powder into a crucible.

3 Hidupkan suis. Perhati dan rekodkan perubahan yang berlaku pada mentol.Turn on the switch. Observe and record the changes that occur in the bulb.

4 Panaskanpepejalplumbum(II)bromidesehinggameleburdanulanglangkah3dan4.Heat solid lead(II) bromide until it melts and repeat steps 3 and 4.

Tujuan

PernyataanMasalah

Hipotesis

PembolehUbah

Bahan

Radas

Prosedur

Lakukan eksperimen ini dalam kebuk wasap. Gas bromin yang terbebas adalah beracun.

Carry out this experiment in the fume chamber. The bromine gas released is poisonous.

BateriBattery

MentolLight bulb

Elektrod karbonCarbon electrode

Pepejal plumbum(II) bromida, PbBr2Solid lead(II) bromidePbBr2

MangkukpijarCrucible

Klip buayaCrocodile clip

SuisSwitch

Segi tigatanah liatPipe claytriangle

+ –


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B. Elektrolisis bagi sebatian ion dalam keadaan akueusElectrolysis of ionic compound in the aqueous state

Rajah (b)/Diagram (b)

1 Sediakan susunan radas seperti yang ditunjukkan pada Rajah (b).Set up the apparatus as shown in the Diagram (b).

2 Hidupkan suis. Perhati dan rekodkan perubahan yang berlaku pada mentol.Turn on the switch. Observe and record the changes that occur in the bulb.

Bahan

SubstanceKeadaan mentolBulb condition

InferensInferences

Pepejalplumbum(II)bromidaSolid lead(II) bromide

Tiada perubahanNo change

Arus elektrik tidak mengalirElectric current does not flow

Leburanplumbum(II)bromidaMolten lead(II) bromide

MentolmenyalaThe bulb lights up

Arus elektrik mengalirElectric current flows

Larutankuprum(II)sulfatCopper(II) sulphate solution

MentolmenyalaThe bulb lights up

Arus elektrik mengalirElectric current flows

1 Mengapakahelektrolisisdapatberlakupadasebatianiondalamkeadaanleburandanakueus? TP2

Why does electrolysis occur in molten and aqueous of ionic compounds?Ion-ionbebasbergerakuntukmengkonduksikanaruselektrik.

Ions are free to move to conduct electricity.

2 Mengapakahelektrolisistidak berlaku pada sebatian ion dalam keadaan pepejal? Why does electrolysis not occur in solid ionic compounds? TP2

Ion-iontidakbebasbergerakuntukmengkonduksikanaruselektrik.

Ions are not free to move to conduct electricity.

1 Adakah hipotesis diterima?/Are the hyphotheses accepted? Ya/Yes

2 Apakah kesimpulan eksperimen ini?/What is the concluion for this experiment?

Sebatian ion dalam keadaan leburan dan akueus boleh menjalani

proses elektrolisis. Sebatian ion dalam keadaan pepejal tidak boleh menjalani proses elektrolisis.

Ionic compounds undergo electrolysis in molten and aqueous states. Ionic

compounds do not undergo electrolysis in solid state.

Pemerhatian

Perbincangan

Kesimpulan

BateriBattery

MentolLight bulb

Elektrod karbonCarbon electrodes

Tabung ujiTest tube

+ –

Larutankuprum(II) sulfat Copper(II) sulphate solution

Klip buayaCrocodile clip

SuisSwitch

+ –

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1 Tandakan ( ✓)faktor-faktoryangmempengaruhihasilelektrolisis. TP1

Tick ( ✓ ) the factors affecting the products of electrolysis.Bilangan sel keringNumber of dry cell ✓

Kedudukan ion dalam siri elektrokimiaPosition of ions in the electrochemical series

✓Jenis elektrod Type of electrode ✓

Kepekatan ion elektrolitConcentration of the electrolyte

2 (a) Kedudukan ion dalam siri elektrokimia/The position of ions in the electrochemical series

Ionyangterletakdibahagianbawahsirielektrokimialebihcenderungdipilihuntukdinyahcasberbanding dengan ion yang terletak di atas siri itu.There is a greater tendency for ions located lower in the electrochemical series to be selected for discharge compared to ions located higher in the series.

Lengkapkansirielektrokimiadibawah./Complete the electrochemical series below. TP1

magnesiummagnesium

kloridachloride

kuprumcopper

iodidaiodide

argentumsilver ion

hidroksidahydroxide

hidrogenhydrogen

Kation/Cation Ionkalium/Potassium ionIonnatrium/Sodium ionIonkalsium/Calcium ion

Ion magnesium/Magnesium ion

Ion aluminium/Aluminium ion

Ion zink/Zink ionIonferum(II)/Iron(II) ionionplumbum(II)ion/Lead(II) ion

Ion hidrogen/Hydrogen ion

Ion kuprum(II)/Copper(II) ion

Ion argentum/Silver ion

Anion/Anion Ionfluorida/Fluoride ionIonsulfat/Sulphate ionIonnitrat/Nitrate ion

Ion klorida/Chloride ion Ionbromida/Bromide ion

Ion iodida/Iodide ion

Ion hidroksida/Hydroxide ion

Semakin mudah dipilih untuk dinyahcasMore easily to be chosen for discharged

Siri elektrokimia/Electrochemical series

(b) Bulatkan ion yang dipilih untuk dinyahcas di anod dan katod. Nyatakan hasil elektrolisis.Kemudian, berikan sebab./Circle the ions chosen to be discharged at anode and cathode. State the products of electrolysis. Then, give reasons. TP2

Tarikh:

AKTIVITIPERBINCANGAN Masteri

PBD6.3 Faktor-faktor yang mempengaruhi hasil elektrolisisFactors affecting the products of electrolysis

IonIons

Ion dipilih untuk dinyahcasIon chosen to be discharged

HasilProduct

(-)AnionAnion

Anod (+) : Ionsulfat IonhidroksidaAnode (+) : Sulphate ion Hydroxide ion

OksigenOxygen

(+)KationCation

Katod (-) : Ionnatrium IonhidrogenCathode (-) : Sodium ion Hydrogen ion

HidrogenHydrogen

Sebab/ReasonAnod :Ion hidroksida terletakdibawahion sulfat dalam siri elektrokimia

Anode : Hydroxide ion is located below sulphate ion in the electrochemical series.

Katod :Ion hidrogen terletakdibawahion natrium dalam siri elektrokimia

Cathode : Hydrogen ion is located below sodium ion in the electrochemical series.


Larutan natrium sulfatSodium sulphatesolutionA


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3 Faktor kepekatan elektrolit./The factor of concentration of electrolyte

Ionyanglebihpekatakandipilihuntukdinyahcasdianod.Jenisionyangdipilihuntukdinyahcasdi katod masih ditentukan oleh kedudukan ion dalam siri elektrokimia.The more concentrated ions will be selected for discharged at the anode. The type of ion chosen for discharge at the cathode is still determined by the position of the ion in the electrochemical series.

Bulatkanionyangdipilihuntukdinyahcasdianoddankatod.Nyatakanhasilelektrolisis.Kemudian,berikan sebab. TP2

Circle the ions chosen to be discharged at anode and cathode. State the products of electrolysis. Then, give reasons.

4 Faktor jenis elektrod/The factor of the types of electrodes

Jika jenis logam yang digunakan sebagai anod adalah sama dengan jenis ion logam yang terdapat di dalam larutan elektrolit, maka anod akan melarut membentuk ion logam itu. Atom logam → ion logam + elektronDikatod,atom-atomlogamtersebutakanterenap. Ionlogam+elektron→ atom logamIf the type of metal used as the anode is the same as the type of metal ion present in the electrolyte solution, then the anode will dissolve to form the metal ions. Metal atom → metal ion + electronAt the cathode, the metal atoms will deposited. Metal ion + electron → metal atom

Berdasarkanfaktorjeniselektrod,nyatakanpemerhatiandanhasildianoddankatod. TP2

Based on the factor of the type of electrode, state the observation and product at the anode and cathode.

ElektrodElectrode

PemerhatianObservation

HasilProduct

AnodAnode

Elektrod kuprum terlarut/menipisCopper electrode dissoves/becomes thinner

Ionkuprum(II)Copper(II) ion

KatodCathode

Elektrod kuprum menebal/Pepejal perang terbentukCopper electrode becomes thicker/A brown solid is deposited.

KuprumCopper

Sebab/ReasonAnod :Ion klorida lebih pekat daripada ion hidroksida .

Anode : Chloride ion is more concentrated than hydroxide ion.

Katod :Ion kuprum(II) terletakdibawahion hidrogen dalam siri elektrokimia.

Cathode : Copper(II) ion is located below hydrogen ion in the electrochemical series.

IonIons

Ion dipilih untuk dinyahcasIon chosen to be discharged

HasilProduct

(-)AnionAnion

Anod (+) : Ionklorida IonhidroksidaAnode (+) : Chloride ion Hydroxide ion

KlorinChlorine

(+)KationCation

Katod (-) : Ionkuprum(II) IonhidrogenCathode (-) : Copper(II)ion Hydrogen ion

KuprumCopper


Larutan kuprum(II)klorida pekatConcentratedcopper(II)chloridesolution

A

Elektrokd kuprumCopper electrodes

Larutan kuprum(II)sulfatCopper(II)sulphatesolution

A

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Tarikh:


PBD6.4 Kedudukan ion dalam siri elektrokimiaThe position of ions in electrochemical series

KBATKBAT

Untuk mengkaji kesan kedudukan ion dalam siri elektrokimia mempengaruhi pemilihan ionuntukdinyahcasTo study the effect of the position of the ion in the electrochemical series that affect the choice of ions to be discharged

Bagaimanakah kedudukan ion dalam siri elektrokimia mempengaruhi pemilihan ion untuk dinyahcas?How does the position of the ions in the electrochemical series affect the choice of ion to be discharged?

Semakin rendah kedudukan ion dalam siri elektrokimia, semakin mudah ionitudinyahcas.

The lower the position of the ions in the electrochemical series, the easier the ions are discharged.

(a) yang dimanipulasikan/that is manipulated: Kedudukan ion dalam siri elektrokimia

Position of ion in the electrochemical series

(b) yang bergerak balas/that responds: Hasil pada elektrod

Products at electrode

(c) yangdimalarkan/that is kept constant:Kepekatan elektrolit dan jenis elektrod

Concentration of electrolyte and type of electrode

Larutan natrium sulfat 0.5 mol dm–3, kayu uji, elektrod karbon, sel elektrolitik, bateri, tabunguji,ammeter,suis,dawaipenyambungdenganklipbuaya,kakiretort.0.5 mol dm–3 sodium sulphate solution, wooden splinter, carbon (graphite) electrode, electrolytic cell, battery, test tubes, ammeter, switch, connecting wires with crocodile clips, retort stand

1 Sediakan susunan radas seperti yang ditunjukkan pada rajah.Set up the apparatus as shown in the diagram.

2 Hidupkansuisdanalirkanaruselektrikselamakira-kira20minit (sehinggatabunguji penuh diisi gas).Turn on the switch and allow the electric current to flow for about 20 minutes (until the test tube is filled with gas).

3 Perhatikanperubahanpadaanoddankatodsertawarnalarutanelektrolit.Observe the changes at the anode and cathode, and the colour of the solution.

4 Uji gas yang terkumpul di dalam tabung uji dengan kayu uji berbara.Collect the gas in a test tube and test it with a glowing wooden splinter.

Tujuan

PernyataanMasalah

Hipotesis

PembolehUbah

Bahan danRadas

Prosedur


A

Larutan natrium sulfatSodium sulphate solution

+ –


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ElektrodElectrode


Ujian gas (jika ada)Gas test (if any)

InferensInference

AnodAnode

Gelembung-gelembunggastidakberwarnaterbebas.Colourless gas bubbles are released.

Gas yang terhasil menyalakan kayu uji berbara.The gas produced lights up the glowing wooden splinter.

Gas oksigen terhasil.Oxygen gas is produced.

KatodCathode


Gas menghasilkan bunyi ‘pop’ dengan kayu uji bernyala.The gas produces a ‘pop’ sound with a burning wooden splinter.

Gas hidrogen terhasil.Hydrogen gas is produced.

1 Tulissemulaformulabagiion-ionyangterdapatdalamlarutannatriumsulfat. TP2

Write all the formulae of ions found in sodium sulphate solution.Ionnatrium,ionsulfat,ionhidrogen,ionhidroksida

Sodium ion, sulphate ion, hydrogen ion and hydroxide ion

2 Tuliskananiondankationyangterdapatdalamlarutankuprum(II)sulfatdalamjadual.Write the anions and cations found in copper(II) sulphate solution in the table. TP2

(a) Anion/Anion : Ionsulfatdanionhidroksida/Sulphate ion and hydroxide ion

(b) Kation/Cation : Ionnatriumdanionhidrogen/Sodium ion and hydrogen ion

3 Tulisformulabagiion-ionyangtertarikke TP2

Write the formulae of ions attracted to the

(a) anod (+)/anode (+) : Ionsulfatdanionhidroksida/Sulphate ion and hydroxide ion

(b) katod (–)/cathode (–) : Ionnatriumdanionhidrogen/Sodium ion and hydrogen ion

4 Tulisformulabagiion-ionyangdipilihuntukdinyahcasdi TP2

Write the formula of ion that is choosen to be discharged at the

(a) anod (+)/anode (+) : ion hidroksida/Hydroxide ion

(b) katod (–)/cathode (–) : Ionhidrogen/Hydrogen ion

5 Mengapakahiontertentudipilihuntukdinyahcasdianoddandikatod? TP2

Why does certain ions are chosen to be discharged at anode and cathode? (a) Di anod/At anode:

Ionhidroksidadipilihkeranaiaberadadibawahionsulfatdalamsirielektrokimia.

Hydroxide ions are chosen because it is located below sulphate ions in the

electrochemical series.

(b) Di katod/At cathode: Ionhidrogendipilihkeranaiaberadadibawahionnatriumdalamsirielektrokimia.

Hydrogen ions are chosen because it is located below sodium ions in the

electrochemical series.


2 Apakah kesimpulan eksperimen ini?/What is the conclusion for this experiment?Semakin rendah kedudukan ion dalam siri elektrokimia, semakin mudah ion itu

dinyahcas.

The lower the position of the ions in the electrochemical series, the easier the ions are

discharged.

Pemerhatian

Perbincangan

Kesimpulan

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PBD6.5 Kepekatan elektrolit dalam elektrolitThe concentration of electrolyte in electrolyte

KBATKBAT

UntukmengkajikesankepekatanelektrolitmempengaruhipemilihanionuntukdinyahcasTo study the effect of the concentration of electrolyte that the choice of ions to be discharged.

Bagaimanakahkepekatanelektrolitmempengaruhipemilihanionuntukdinyahcas?How does the concentration of electrolyte affect the choice of ion to be discharged?

Ionyanglebih tinggi kepekatannyaakandipilihuntukdinyahcaspadaanod

Ions with higher concentration will be chosen to be discharged at anode

(a) yang dimanipulasikan/that is manipulated: Kepekatan ion dalam elektrolit/Concentration of ion in electrolyte

(b) yang bergerak balas/that responds: Hasil pada anod/Product at anode

(c) yangdimalarkan/that is kept constant: Jenis elektrod/Type of electrode

Asidhidroklorik0.0001moldm–3,asidhidroklorik1moldm–3

0.0001 mol dm–3 hydrochloric acid, 1 mol dm–3 hydrochloric acid

Elektrod karbon, kayu uji, sel elektrolitik, bateri, tabung uji, ammeter, suis, dawaipenyambung dengan klip buaya, kaki retort.Carbon electrodes, wooden splinter, electrolytic cell, battery, test tube, ammeter, switch, connecting wires with crocodile clips, retort stand

1 Sediakan susunan radas seperti yang ditunjukkan pada rajah.Set up the apparatus as shown in the diagram.

2 Hidupkansuisdanalirkanaruselektrikselamakira-kira20minit (sehinggatabunguji penuh diisi gas).Turn on the switch and allow the electric current to flow for about 20 minutes (until the test tube is filled with gas).

3 Perhatikanperubahanpadakedua-duaelektrod.Observe the changes at the two electrodes.

4 Uji gas yang terkumpul di anod dan katodmasing-masing dengan kayu uji berbaradan kayu uji bernyala.Collect the gases at the anode and cathode, and test with a glowing wooden splinter and a lighted wooden splinter respectively.

5 Ulangieksperimendenganmenggunakanasidhidroklorik0.0001moldm–3

Repeat the experiment using 0.0001 mol dm–3 hydrochloric acid. 6 Ujigasyangterkumpuldianoddankatodmasing-masingdengankertaslitmusmerah

lembap dan kayu uji bernyala.Test the gases collected at the anode and cathode each with a damp red litmus paper and a lighted wooden splinter respectively.

Tujuan

PernyataanMasalah

Hipotesis

PembolehUbah

Bahan

Radas

A


Larutan elektrolitElectrolyte solution

+ –

Prosedur


BAB

6

82

1 mol dm–3 asid hidroklorik (pekat)/1 mol dm–3 hydrochloric acid (concentrated)

0.0001 mol dm–3 asid hidroklorik (cair)/0.0001 mol dm–3 hydrochloric acid (dilute)

1 Kepekatan ion klorida dalam asid hidroklorik yang manakah lebih tinggi, dalam 1.0moldm–3atau0.0001moldm–3? TP2

Concentration of chloride ion in which hydrochloric acid is higher, in 1.0 mol dm–3 atau 0.0001 mol dm–3? 1.0moldm–3

2 Namakanhasilyangterbentukpadaanodbagisetiapelektrolitdibawah. TP2

Name the product formed at anode for each electrolyte below. (a) Asidhidroklorik1.0moldm–3/1.0 mol dm–3 hydrochloric acid:

Gas klorin/Chlorine gas

(b) Asidhidroklorik0.0001moldm–3/0.0001 mol dm–3 hydrochloric acid: Gas oksigen/Oxygen gas

3 Namakanionyangdipilihuntukdinyahcaspadaanodbagi: TP2

Name the ions chosen for discharge at the anode for: (a) Asidhidroklorik1.0moldm–3/1.0 mol dm–3 hydrochloric acid:

Ionklorida/Chloride ion

(b) Asidhidroklorik0.0001moldm–3/0.0001mol dm–3 hydrochloric acid: Ionhidroksida/Hydroxide ion


2 Apakah kesimpulan eksperimen ini?/What is the conclusion for this experiment?Ionyanglebihtinggikepekatannyaakandipilihuntukdinyahcaspadaanod.

Ions with higher concentration will be chosen to be discharged at anode.

Pemerhatian

ElektrodElectrode



InferensInference

AnodAnode

Gelembung-gelembunggas kuning kehijauan terbebas.Greenish-yellow gas bubbles are released.

Gas yang terhasil melunturkan kertas litmus merah lembap. The gas produced bleaches the damp red litmus paper.

Gas klorin terhasil.Chlorine gas is produced.

KatodCathode


Gas menghasilkan bunyi ‘pop’ dengan kayu uji menyala.The gas produces a ‘pop’ sound with a burning wooden splinter.


ElektrodElectrode



InferensInference

AnodAnode


Gas yang terhasil menyalakan kayu uji berbara.The gas produced lights up/ignites the glowing wooden splinter.


KatodCathode

Gelembung-gelembunggastidakberwarnaterbebas. Colourless gas bubbles are released.

Gas menghasilkan bunyi ‘pop’ dengan kayu uji menyala. The gas produces a ‘pop’ sound with a burning wooden splinter.


Perbincangan

Kesimpulan

BAB

6

83

Tarikh:


PBD6.6 Jenis elektrod mempengaruhi hasil elektrolisisThe type of electrode affects the products of electrolysis

KBATKBAT

UntukmengkajikesanjeniselektrodmempengaruhipemilihanionuntukdinyahcasTo study the effect of the types of electrode that affect the choice of ions to be discharged

Bagaimanakahjeniselektrodmempengaruhipemilihanionuntukdinyahcas?How does the type of electrode affect the choice of ion to be discharged?

1 Jikaelektrodkarbondigunakan semasaelektrolisis larutankuprum(II) sulfat,maka

ion hidroksida dipilihuntukdinyahcasdianod.If carbon electrodes are used during electrolysis of copper(II) sulphate solution, then

ion hydroxide is chosen for discharge at anode. 2 Jikaelektrodkuprumdigunakansemasaelektrolisislarutankuprum(II)sulfat,maka

ionkuprum(II) terhasil di anod. If copper electrodes are used during electrolysis of copper(II) sulphate solution, then

copper(II) ions are produced at the anode.

(a) yang dimanipulasikan/that is manipulated: Jenis elektrod (karbon atau kuprum)

Type of electrode (carbon or copper)

(b) yang bergerak balas/that responds: Hasil elektrolisis terbentuk di elektrod

Product of elelctrolysis at the anode

(c) yangdimalarkan/that is kept constant: Jenis dan kepekatan elektrolit

Type and concentration of electrolyte

Larutankuprum(II)nitrat0.5moldm–3, elektrod karbon, elektrod kuprum, kayu uji, sel elektrolitik,bateri,tabunguji,ammeter,suis,dawaipenyambungdenganklipbuaya,kakiretort.0.5 mol dm–3 copper(II) nitrate solution, carbon electrodes,, copper electrodes, wooden splinter, electrolytic cell, battery, test tube, ammeter, switch, connecting wires with crocodile clips, retort stand.

1 Sediakan susunan radas seperti dalam rajah. Set up the apparatus as shown in the diagram. 2 Hidupkansuisdanalirkanaruselektrikselamakira-kira20minit. Turn on the switch and allow electricity to flow for about 20 minutes. 3 Perhatikanperubahanpadakedua-duaelektrodkarbon. Observe the changes at both copper electrodes.

Tujuan

PernyataanMasalah

Hipotesis

PembolehUbah

Bahan

Prosedur

A

Elektrod karbonCarbon electrodes Larutan kuprum(II) nitrat

Copper(II) nitrate solution


BAB

6

84

4 Uji gas yang terbebas di anod dengan menggunakan kayu uji berbara.Test the gas released at the anode using a glowing wooden splinter.

5 Ulang langkah 1 hingga 3 dengan menggantikan elektrod karbon dengan elektronkuprum./Repeat steps 1 till 3 by replacing carbon electrodes with copper electrodes.

ElektrodElectrode


InferensInference

KarbonCarbon

AnodAnode

Gas terbebas menyalakan kayu uji berbara.The gas released lights up the glowing wooden splinter.


KatodCathode

Pepejal perang terenap.Brown solids are deposited.

Kuprum terhasil.Copper is produced.

KuprumCopper

AnodAnode

Elektrod kuprum terlarut/menjadi nipis.Copper electrode dissolves/becomes thinner.

Ionkuprum(II)terhasil.Copper(II) ions are produced.

KatodCathode

Elektrod kuprum menebal/Pepejal perang terenap.Copper electrode becomes thicker/Brown solids are deposited.

Kuprum terhasil.Copper is produced.

1 Namakanionyanghadirdalamelektrolit./State the ions present in the electrolyte. TP1

Ionkuprum(II),ionnitrat,ionhidrogendanionhidroksida.

Copper(II) ion, nitrate ion, hydrogen ion and hydroxide ion.

3 Namakan ionyangdipilihuntukdinyahcasdianoddankatodbagielektrod-elektrodkarbon dan tuliskan hasil yang terbentuk dalam petak. TP2

Name the ion chosen for discharge at the anode and cathode for carbon electrodes and write the products formed in the boxes.

Hasil yang terbentuk/Product formed

(a) Anod : Ionhidroksida

Anode : Hydroxide ion Gas oksigen/Oxygen gas

(b) Katod : Kuprum(II)ion

Cathode : Copper(II) ion Kuprum/Copper

4 Namakanionyangterhasildianoddanhasilyangterbentukdikatodbagielektrod-elektrod kuprum./Name the ion produced at the anode and the product formed at the cathode for the copper electrodes. TP2

(a) Anod/Anode: Ionkuprum(II)/Copper(II) ion

(b) Katod/Cathode: Logam kuprum/Copper metal


2 Apakah kesimpulan eksperimen ini?/What is the conclusion for this experiment?Jikaelektrodkarbondigunakansemasaelektrolisislarutankuprum(II)sulfat,makaion

hidroksidadipilihuntukdinyahcasdianod.Jikaelektrodkuprumdigunakansemasa

elektrolisislarutankuprum(II)sulfat,makaionkuprum(II)terhasildianod./If carbon

electrodes are used during electrolysis of copper(II) sulphate solution, then hydroxide

ion is chosen for discharge at anode. If copper electrodes are used during electrolysis

of copper(II) sulphate solution, then copper(II) ions are produced at the anode.

Pemerhatian

Perbincangan

Kesimpulan

BAB

6

85

Modul Teknologi Hijau KIMIA, CETREE USM. Tajuk: Mewajarkan Teknologi Hijau dalam Elektrokimia.

Lengkapkan ruang tentang aplikasi elektrolisis dalam industri. TP2

Complete the spaces about the application of electrolysis in industry.

1 Pengekstrakan logam/Extraction of metals

Logam-logam yang (kurang, lebih) reaktif daripada karbon seperti kalium, natrium, kalsium,magnesium, dan aluminium perlu diekstrakkan daripada leburan (logamnya, bijihnya) melalui (elektrolisis, pemanasan dengan karbon). Leburan (logam, bijih) dijadikan elektrolit dan elektrod-elektrod (kuprum, karbon) digunakan sebagai elektrod.Metals that are (less, more) reactive than carbon such as potassium, sodium, calcium, magnesium, and aluminum need to be extracted from its molten (metal, ore) by (electrolysis heating with carbon). The molten (metal, ore) is used as electrolyte and (copper, carbon) is used as the electrodes.

2 Penyaduran/Electroplating (Faktor jenis elektrod/Factor of the type of electrode)

Dalamprosespenyaduransecaraelektrolisis,logampenyadurdijadikan(anod, katod) manakala logam yang hendak disadur dijadikan (anod, katod). Elektrolit yang digunakan ialah (leburan, larutan akueus) yang mengandungi ion logam penyadur.In an electroplating process, the plating metal is the (anode, cathode) while the metal to be plated is the (anode, cathode). The electroiyle used is (molten, an aquenous solution) containing the metal ion for the plating.

3 Penulenan logam/Purification of metal (Faktor jenis elektrod/Factor of the type of electrode)

Proses penulenan logam menggunakan prinsip yang sama seperti proses penyaduran logam. Dalam proses penulenan, logam tidak tulen dijadikan (anod, katod) manakala kepingan logam tulen dijadikan (anod, katod).Elektrolityangdigunakanialahlarutanyangmengandungiion-ionlogamitu.The process of the purification of metals uses the same principle as the electroplating process. In the purification process, the impure metal is made the (anode, cathode) while a pure metal plate is made the (anode, cathode). The electrolyte used is a solution containing the metal ions.

4 Pengolahan air sisa dengan menggunakan elektro-penggumpalan Waste water treatment by electrocoagulation

Pada anod, elektrod logam seperti aluminium dalam elektrolit menghasilkan ion (aluminium, hidrogen). Penggumpalan berlaku apabila ion (aluminium, hidrogen) dan ion hidroksida serta bahan pencemarbergabung. Gumpalan ini disebut (kristal, flok) yang kemudian tenggelam dan berkumpul pada dasar.At the anode, a metal electrode such as aluminium ionises in the electrolyte to produce (aluminium, hydrogen) ions. Coagulation occurs when (aluminium, hydrogen) ions and pollutants in the waste water combine to produce coagulants. This coagulant is knows as a (crystal, floc) that sinks and gathers at the base.

Tarikh:

AKTIVITIPERBINCANGAN Kontekstual

PBD6.7 Aplikasi elektrolisis dalam industriApplication of electrolysis in industry

AnodAnode

AluminiumoksidaMolten aluminium oxide

Aluminium leburMolten aluminium

Katod karbonCarbon cathode

Tangki keluliSteel tank

+

–


BAB

6

86

Modul Teknologi Hijau KIMIA, CETREE USM. Tajuk: Mewajarkan Teknologi Hijau dalam Elektrokimia.2007 BHG. C, S11(a)

Mengkajipenghasilantenagaelektrikolehselringkas To study the production of electrical energy by a simple cell

Kepinganzink,kepingankuprum,larutannatriumklorida,wayarpenyambung,klipbuaya,bikar, voltmeter/Zinc plate, copper plate, sodium chloride solution, connecting wires, crocodile clips, beaker, voltmeter

1 Sediakan susunan radas seperti yang ditunjukkan dalam rajah.

Set up the apparatus as shown in the diagram. 2 Tuangkan larutan natrium klorida ke dalam

bikar. Pour sodium chloride solution into a beaker. 3 Celup kepingan zink dan kepingan kuprum

ke dalam larutan natrium klorida. Dip zinc and copper plates into the sodium

chloride solution. 4 Sambungkan kepingan zink dan kepingan

kuprumdenganwayarpenyambungkepadavoltmeter.

Connect the zinc and copper plates with connecting wires to the voltmeter.

5 Rekodkanbacaanvoltmeter.Record the voltmeter reading.

6 Ulanglangkah1hingga5denganmenggunakanduakepinganzinksebagaipasangan logam./Repeat steps 1 till 5 using two zinc plates as the metal pair.

Pasangan logamMetal pairs

Bacaan voltmeterVoltmeter reading (V)

Zink dan kuprum/Zinc and copper 1.1

Zink dan zink/Zinc and zinc 0

1 Nyatakaninferensyangbolehdibuatberdasarkanpemerhatianbagieksperimenini.State the inference that can be made based on the observation of this experiment. TP2

Arus elektrik terhasil.Electric current is produced.

2 Nyatakanperubahantenagayangberlakudalamselringkasini. TP2

State the energy change that occurs in this simple cell.

Tenaga kimia kepada tenaga elektrik .Chemical energy to Electrical energy.

3 Ramalkanbacaanvoltmeterjikapasanganlogamkuprumdankuprumdigunakan. TP2

Predict the voltmeter reading if the metal pair of copper and copper is used.0V

Apakah kesimpulan yang dapat dibuat daripada aktiviti ini? What conclusion can be made from this activity?

Dua logam berlainan yang dicelup ke dalam satu elektrolit menghasilkan arus elektrik .

Two different metals dipped in an electrolyte produce electric current .

Tujuan

Bahan danRadas

Prosedur

KepinganzinkZinc plate

Larutan natrium kloridaSodium chloride solution

KepingankuprumCopperplate

V

Keputusan

Perbincangan

Kesimpulan

Standard Kandungan6.2 Sel kimia Tarikh:


PBD6.8 Penghasilan tenaga elektrik oleh sel ringkasThe production of electrical energy by a simple cell

KBATKBATBuku teks m/s 192 – 195

BAB

6

87

Kertas 1

PRAKTIS PENGUKUHAN 6SPM

Arahan: Setiap soalan diikuti oleh empat pilihan jawapan, A, B, C dan D. Pilih jawapan yang terbaik.Instructions: Each question is followed by four options A, B, C and D. Choose the best answer.

1 Logam yang manakah boleh diekstrak daripada bijihnya hanya melalui proses elektrolisis?/Which metal can be extracted from its ore only by the process of electrolysis?A Magnesium/Magnesium B Timah/TinC Kuprum/CopperD Plumbum/Lead

2 Rajah 1 menunjukkan suatu sel kimia./Diagram 1 shows a chemical cell.

V

Larutan garamsalt solution

PKuprumCopper

Rajah 1/Diagram 1

Jika jarum volmeter tidak terpesong, apakah P?If the volmeter needle does not deflect, what is P?A Karbon/CarbonB Zink/ZincC Kuprum/CopperD Besi/Iron

3 Rajah 2 menunjukkan susunan radas elektrolisis untuk menyadur sebatang paku besi.Diagram 2 shows the electrolysis apparatus set up to electroplate an iron nail.

Logam XMetal X Paku besi

Iron nail

LarutanargentumnitratSilver nitratesolution

A

Rajah 2/Diagram 2

Apakah logam X?What is metal X?A Argentum/SilverB Besi/IronC Aluminium/AluminiumD Kuprum/Copper

KLON SPM 2004/2007/2011/2013

Soalan 4 dan 5 berdasarkan Rajah 3.Ouestions 4 and 5 are based on Diagram 3.

4 Rajah 3 menunjukkan satu proses penulenan.Diagram 3 shows a purification prosess.

Kepingan kuprumTidak tulen, Ximpure copperPlate, X

Kepingan kuprum tulenPure copper plateLarutan PSolution P

Rajah 3/Diagram 3

Antara yang berikut, yang mana kah X dan larutan P?Which of the following are X and solution P?

X P

A Kation/Cation Kalium nitrat/Potassium nitrate

B Katod/Cathode Kuprum(II) nitrat/Copper(II) nitrate

C Anod/Anode Kuprum(II) sulfat/Copper(II) sulphate

D Anion/Anion Zink klorida/Zinc chloride

KLON SPM 2007/2008

5 Apakah yang akan berlaku kepada anod? What will happen to the anode?

A Menjadi lebih nipis C Menjadi lebih tebalBecomes thinner Becomes thicker

C Kuprum terenap D Gelembung gas terbentukCopper is deposited Gas bubbles are formed

KLON SPM 2014

6 Antara proses yang berikut, yang manakah boleh digunakan untuk mengelakkan pengaratan objek besi?Which of the following processes can be used to prevent rusting of iron objects?A Penyaduran

ElectroplatingB Pengekstrakan

ExtractionC Penulenan

PurificationD Penghabluran

Crystallisation

7 Logam yang manakah diekstrak daripada bijihnya dengan menggunakan elektrolisis?Which metals is extracted using electrolysis?I Kalsium/CalciumII Aluminium/AluminiumIII Natrium/Sodium IV Zink/ZincA I dan II/I and IIB II dan III/II and IIIC I, II dan III/I, II and IIID I, II, III dan IV

I, II, III and IVKLON SPM 2006/2008

BAB

6

88

Kertas 2

Arahan: Jawab semua soalan.Instructions: Answer all the questions.

Bahagian B/Section B

1 Rajah di bawah menunjukkan satu model sel ringkas.The diagram below shows a model of a simple voltaic cell.

(a) Apakah yang dapat diperhatikan pada voltmeter? What can be observed on the voltmeter? Jarum voltmeter terpesong.

The pointer of the voltmeter is deflected.

[1 markah/1 mark]

(b) Berikan inferens kepada pemerhatian di 1(a)./Give an inference to the observation in 1(a).

Arus elektrik terhasil/An electric current is produced

[1 markah/1 mark]

(c) Tulis perubahan tenaga yang berlaku dalam eksperimen ini.Write the energy transformation that occurs in this experiment.Tenaga kimia kepada tenaga elektrik/Chemical energy to electrical energy

[1 markah/1 mark]

(d) (i) Apakah yang akan berlaku jika kepingan kuprum digantikan dengan rod karbon? What will happen if the copper plate is replaced with a carbon rod?

Jarum voltmeter terpesong./The pointer of the voltmeter is deflected.

[1 markah/1 mark]

(ii) Berikan sebab bagi jawapan anda di 1(d)(i)./Give a reason for your answer in 1(d)(i).Rod karbon mengkonduksikan arus elektrik./The carbon rod conducts electric current.

[1 markah/1 mark]

(e) Nyatakan satu contoh makanan yang dapat digunakan untuk menggantikan larutan cuka.State one example of a food item which can be used to replace the vinegar solution.Jus nanas/Jus oren/Pineapple juice/Orange juice

[1 markah/1 mark]

Bahagian C/Section C

2 Kaji pernyataan yang berikut./Study the following statement.

Dua logam berlainan yang dicelup ke dalam larutan elektrolit menghasilkan arus elektrik.Two different metals that are dipped in an electrolyte solution produce electric current.

(a) Nyatakan satu pernyataan masalah daripada maklumat di atas. State one problem statement from the above information. [1 markah/1 mark]

(b) Cadangkan satu hipotesis untuk mengkaji pernyataan di atas.Suggest one hypothesis to investigate the above statement. [1 markah/1 mark]

(c) Berdasarkan pernyataan yang diberi, reka bentuk satu eksperimen makmal untuk menguji hipotesis anda dengan menggunakan kepingan zink, kepingan kuprum, kepingan besi, larutan natrium klorida, bikar, voltmeter, klip buaya dan wayar penyambung.Based on the given statement, design a laboratory experiment to test your hypothesis by using zinc plate, copper plate, iron plate, sodium chloride solution, beaker, voltmeter, crocodile clips and connecting wire

Huraian anda harus mengandungi aspekaspek berikut: Your description should include the following aspects:

(i) Tujuan eksperimen/Aim of the experiment [1 markah/1 mark]

(ii) Mengenal pasti pemboleh ubah/Identification of the variables [2 markah/2 marks]

(iii) Prosedur/Procedure [4 markah/4 marks]

(iv) Penjadualan data/Tabulation of data [1 markah/1 mark]

V

Kepingan zinkZinc plate

Kepingan kuprumCopper plate

CukaVinegar

Praktis SPM

BAB

6

89

TEMA 2: Penerokaan Unsur dalam Alam BAB 6 Elektrokimia ...

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