t4. Bab 5-Tenaga Dan Perubahan Kimia

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Chapter 5

Energy and Chemical Changes

Tingkatan PCKBy

CHE AHAMAD BIN DAUD



5.1 Understanding physical and chemical changes

Student will be able to :

explain what physical change is,explain what chemical change is,

give examples of physical changes in daily life,

give examples of chemical changes in daily life,Compare and contrast physical changes and

chemical changes.

2



ENERGY CHANGES

CHEMICAL CHANGES PHYSICAL CHANGES

3

http://g/PPK%202009%20EDITED%20Sains%20Teras%20Men%20Atas/CHEMICAL%20CHANGES.ppt




EXAMPLE 1 REVIEW 1

EXAMPLE 2

REVIEW 2

EXAMPLE 3

REVIEW 3

4



ENERGY CHANGES

EXOTHERMICREACTION

CHEMICAL CHANGES

ENDOTHERMICREACTION

PHYSICAL CHANGES

5







Chemical Change Physical change

Similarities

Substances can undergo changes ..............................

Differences

New substances formed

Change in chemical composition

Reversibility

Energy needed

SIMILARITIES AND DIFFERENCES BETWEEN CHEMICALS

AND PHYSICAL CHANGES

physica l ly

Less

Yes

Yes

More

No

Easy

No

Dif f icul t

6



7



THE END…

8



A physical change is a change whichdoes not produce a new substance. Only the

physical state of the substance has

changed.

BACK

9



A chemical change is a changewhich produces a new substance. The new

substance has chemical properties and

composition different from the originalsubstance.

BACK

10



Iodine crystal

Ice cube

Iodine crystal

is heated, it

changes fromsolid to gas

Watch glass

11



Iodine crystalpurple vapour(Iodine vapour)

Ice cube

Watch glass

12



Iodine crystal

Ice cube

Watch glass

13



Iodine crystal

Ice cube

Watch glass

14



Iodine crystal

purple vapour(Iodine vapour)

Ice cube

Watch glass

15



Iodine crystal

Ice cube

Watch glass

16



Iodine crystal

Ice cube

Watch glass

17



Iodine crystal

Ice cube

Watch glass

18



Iodine crystal

purple vapour(Iodine vapour)

Ice cube

Watch glass

19



Iodine crystal

Black crystal

Ice cube

Watch glass

20



Iodine crystal

Black crystal

Ice cube

Watch glass

21



Black crystal

Ice cube

Watch glass

22



Black crystal

Ice cube

Watch glass

23



Black crystal

Ice cube

Watch glass

24



Black crystal

(iodine)Iodine vapour

Ice cube

Watch glass

BACK

25




• When the ………….. is heated, purple …………

is formed.

• Iodine changes from ………….to ……… without

going through the ……….. state (sublimation).

• When the iodine vapour…………… the cold

………….. of the watch glass, the vapour changesback into ……….. state (black crystal).

• Solid ……………. forms on the lower surface

of the watch glass.

• The change of solid iodine into iodine vapour is

……………..

• This is a ………….change.

iodine vapour

solid gasliquid

touches

surface solid

iodine

reversible

physicalBACK

26





ICE CUBE

BACK

27




Water and ................ have the ...................... particles.

The differences between water and ice are in terms of the

...............................and ......................... of the particles.

Ice can easily ................... into .................. when it is

.......................

Is this a reversible process ? ........................

Is energy absorbed or released ? ...........................

Is new product formed ? .....................

ice same

arrangement movement

change

Absorbed

heated

water

Yes

No

BACK

28




Back29






The magnesium .................... burns with a ............... flame and

forms .............. ash.

During the process:- ..................... and .................... are given off.

- Magnesium combines with ...................in the air to

form ………......................

- .................................. is different from

..................................,

Is this a reversible process ?........................


Is new product formed ? .....................

r ibbon

heat

whi te

br ight

l ight

oxygen

magnes ium oxide

magnes ium oxide

magnes ium

magnes ium oxide

No

Yes

Magnesium + oxygen ………………………. (white ash )

(grey metal)

Released

BACK

30




Iron nails ........................... when ........................ and .........................

are present.

Rusts is a ................. substance that consists of................................

Is this reversible process ? .....................


Is new product formed ?.....................

................... + Oxygen + .................... ............................. (Rust)

rust oxyg en water

b rown iron oxide

Iron Water Iron ox ide

No

Absorbed

Yes

BACK

31




An endothermic reaction is a reaction

which absorbs heat energy from the

surroundings.

BACK

32




An exothermic reaction is a reaction which

releases heat energy to the surroundings.

BACK

33




34



35



36



37



5.2 Analysing heat change in chemical reactions

Student will be able to :

State that chemical reactions involve heat change,

Identify reactions involving heat lost,Identify reactions involving heat gain,

Relate changes in temperature of reactants toexothermic reactions,

Relate changes in temperature of reactants toendothermic reactions,

Explain through examples heat changes that occurduring industrial chemical reaction.

38



You are given ammonium chloride and sodium hydroxide as the

chemical substances.

Heat is absorbed or released during a chemical reaction

a. Based on the above statement, write a suitable hypothesis.

(1 mark)

b. Describe an experiment that you can carry out in the laboratory toprove this hypothesis.

Your description should contain the following:

i. Aim of the experiment (1 mark)

ii. Identify the variables (2 marks)

iii. List of apparatus and materials (1 mark)

iv. Method (4 marks)

v. Tabulation of data (1 mark) 39



STATEMENT

WHAT I WANT TO CHANGE

MVWHAT IS FIXED

CVWHAT I SHOULD MEASURE

RV

WHEN I CHANGE, WHAT WILL HAPPEN TO WHAT I MEASURE (HYPOTHESIS)

WHY I DO … (AIM) To study ………………..

METHOD I USE ………………

PRO EDURE

DATA THAT I WANT TO COLLECT (TABULATION OF DATA)

WHAT I CHANGE WHAT I MEASURE

WHAT APPARATUS& MATERIALS ?

1

2 3

4

5

67

8

9

Diagram

40

WHY I DO (AIM)5




WHAT I WANT TO CHANGE

MVWHAT IS FIXED


RV




PRO EDURE




1

2 3

4

5

67

8

9

Diagram

41

WHY I DO (AIM)5




TYPE OF SUBSTANCE

MV WHAT IS FIXED


RV




PRO EDURE




1

2 3

4

5

67

8

9

Diagram

42

WHY I DO (AIM)5




TYPE OF SUBSTANCE MV

WHAT IS FIXED

CVFinal Temperature

RV




PRO EDURE




1

2 3

4

5

67

8

9

Diagram

43

WHY I DO (AIM)5




TYPE OF SUBSTANCE

MVWHAT IS FIXED

CVFinal Temperature

RV

Heat is absorbed or released during a chemical reaction.



PRO EDURE



WHAT APPARATUS& MATERIALS

1

2 3

4

5

67

8

9

Diagram

44

5




TYPE OF SUBSTANCEMV

WHAT IS FIXED

CVFinal Temperature

RV


To study that heat is absorbed or released during chemical reaction


PRO EDURE



WHAT APPARATUS& MATERIALS

1

2 3

4

5

67

8

9

Diagram

45



46

5





WHAT IS FIXED

CVFinal Temperature

RV



1. Pour 10 ml of distilled water into each test tube A, B & C

and record the initial temperature.

2. Add a spatula of ammonium chloride into test tube B and stir .

3. Add a spatula of sodium hydroxide into test tube C and stir.

4. Maintain test tube A as a control.

5. Record the final temperature in a table.




1

2 3

4

5

6

7

8

9

Diagram

47

5




TYPE OF SUBSTANCEMV

WHAT IS FIXED

CVFinal Temperature

RV




and record the initial temperature.2. Add a spatula of ammonium chloride into test tube B and stir .


4. Maintain test tube A as a control.5. Record the final temperature in a table.



test tube,thermometer, spatula,

Ammonium chloride,Sodium hydroxide &

Distilled water

1

2 3

4

5

67

8

9

Diagram

48

5





WHAT IS FIXED

CVFinal Temperature

RV



.







DATA THAT I WANT COLLECT (TABULATION OF DATA)


test tube,

thermometer, spatula, Ammonium chloride,

Sodium hydroxide &

distilled water

1

2 3

4

5

6

7

8

9

Diagram

Test tube Initial Temperature (oC) Final temperature (oC) AB

8 49

5




TYPE OF SUBSTANCE

MVVolume of distilled water

CVFinal Temperature

RV









DATA THAT I WANT COLLECT (TABULATION OF DATA)


test tube,

thermometer, spatula,

Ammonium chloride,Sodium hydroxide &

distilled water

1

2 3

4

5

6

7

8

9

Diagram

Test tube InitialTemperature (oC) Final temperature (oC)

A

BC

8 50



a. Hypothesis : Heat is absorbed or released during a chemicalreaction depends on type of substances used

b. i. Aim : To study that heat is absorbed or released during a

chemical reaction

ii. Variables :manipulated : type of substances

responding : Final temperature

constant : volume of distilled water//Initial temperature

iii. Apparatus & materials : test tube, spatula, thermometer,ammonium chloride, sodium hydroxide and distilled water.

51



iv. Procedure :


and record the initial temperature.2. Add a spatula of ammonium chloride into test tube B and stir .




52



TABULATION OF DATA :

TEST TUBE INITIALTEMPERATURE (oC) FINALTEMPERATURE (oC)

A

B

C

53



54



55



56

Learning area:



Learning area:

5. Energy and chemical changes

Learning Objectives :

5.3 Synthesizing the reactivity series of metal

Learning Outcomes :

A student is able to :

•Describe the reactivity of metals with water, diluteacid and oxygen

•Compare and contrast the reactivity of metals with

water, acid and oxygen

•Arrange metals in order of reactivity with water, acidand water

•Identify the carbon in the reactivity series

•Construct the reactivity series of metals based on

reactivity of metal with oxygen 57

A REACTIVITY OF METALS WITH



The reaction of metal with water will produce

hydrogen gas and alkali

A.REACTIVITY OF METALS WITH

WATER

58



• Sodium and calcium (very active metal )

reacts very fast in cold water.

• Magnesium, aluminium and zinc (less

active metal ) reacts with hot water or

steam.

• Non active metals such as gold and silver

do not react with either water or steam.

59



Chemical equations

Sodium + Water Sodium + hydrogen

hydroxide

Magnesium + Water Magnesium + hydrogen

hydroxide

For experiment : Refer to

Appendix 160

B. REACTIVITY OF METALS WITH

http://g/PPK%202009%20EDITED%20Sains%20Teras%20Men%20Atas/Appendix/Appendix-2.ppt






DILUTE ACID Some metals react with dilute acid to produce

salt and hydrogen

General equation:

METAL + ACID SALT + HYDROGEN

Magnesium, aluminium and zinc react with dilute

acid

Copper, silver and gold do not react with dilute

acid

61

2 Type of salt produced



2.Type of salt produced

depends on the type of acid

used.

Examples:

Zinc + sulphuric acid zinc sulphate + hydrogen

Magnesium + sulphuric acid magnesium sulphate + hydrogen

Aluminium + sulphuric acid Aluminium sulphate + hydrogen

62

C REACTIVITY OF METALS WITH OXYGEN



C. REACTIVITY OF METALS WITH OXYGEN

When heated in ......................, most metals react with

.......................to form ...........................

General equation

The more reactive the metal, the ...........................

the flame produced.

Metal + Oxygen ...........................

air

o xygen metal oxide

br ighter

metal oxide

For experiment : Refer toAppendix 2 63

Th ti it f t l ith







The reactivity of metals with oxygen

depends on the reactivity series

Metal + Oxygen Metal oxide

+ o xygen

Zinc

Iron

Zinc oxide+ oxygen

Iron oxide

For experiment :Refer to Appendix 3

64

S b l R ti it M t lReaction with Reaction with Reaction with Reaction with







Symbol Reactivity MetalReaction with

water

Reaction with

steam

Reaction with

acid

Reaction with

oxygen

Most

Reactive Potassium Hydrogen

gas released

Metal

hydroxidesformed

Explosion Explosion

Violent

reaction

Burn brightly

forming oxidesSodium

Calcium

Magnesium No reaction Hydrogen gas

released

Metal oxides

formed

React fast

Hydrogen gas

released

Metal salts

formed

Aluminium No reaction Burn if strongly

heated

Zinc No reaction

Iron No reaction

Tin (Stanum) No reaction No reaction React slowly

Hydrogen gas

released

Metals do not

burn but oxide

layer formedLead No reaction No reaction

Copper No reaction No reaction No reaction

Silver No reaction No reaction No reaction No reaction

Least

Reactive

Gold No reaction No reaction No reaction No reaction

Platinum No reaction No reaction No reaction No reaction

K

Na

Ca

Mg

A l

Zn

Fe

Sn

Pb

Cu

Ag

Au

Pt

65



Carbon and reactivity series

• Metal compounds higher up in thereactivity series are more stable (noteasily decomposed by heat).

• These metal compounds can only bedecomposed by electrolysis.

• Example:

Decomposition of sodium chloride byelectrolysis.

66



• Compounds of metals lower down in the

reactivity series are less stable and can be

decompose easily by heating.

• These metal oxides can be reduced by

carbon (reducing agent) into metal and

carbon dioxide.• Example:

Zinc oxide + Carbon Zinc +Carbondioxide

67

Symbol Reactivity Reaction of metal oxides with carbon



y y

Mg No reaction

Al No reaction

C

Zn Less active

Fe Active

Sn More active

Pb Most active

Least active

Most active

68



Energy andchemical changes

WaterOxygenAcid

Reactivityof metals

with

Reaction of metaloxides with carbon

Extraction of metal oresby carbon

and electrolysis

69



REVISION

• Refer Appendix-4

• My Experiment Sheet

70

http://g/PPK%202009%20EDITED%20Sains%20Teras%20Men%20Atas/Appendix/My-exp%20sheets.doc




All the best!!!!!!!

71

http://g/BENGKEL%20KURIKULUM/Funny/Funny/f18vsf1.mpeg



72



73



5.4 Applying the concepts

of the reactivity series

of metal

74





• 5.4 Applying the concepts of the reactivity series

of metal

Learning Outcomes :


• Relate the position of metals in the reactivity series tothe method of extraction of metals from their ores.

• Explain with examples the process of extraction of a

metal from its ore using carbon.

• State the importance of the reactivity series.

75

CONCEPTS OF REACTIVITY



SERIES• A more reactive metal can take oxygen

from the oxide of other less reactive metal

to form the less reactive metal and the

oxide of the more reactive metal.

• Example: Aluminium + iron oxide iron + aluminium oxide

Morereactivemetal

Oxide of lessreactive metal

Lessreactivemetal

Oxide of moreReactive metal

76



• A more reactive non-metal (carbon)

also can take oxygen from the oxide of

other less reactive metal to form theless reactive metal and carbon dioxide.

• Example:

Carbon + iron oxide iron + carbon dioxide

Morereactivenon-metal

Oxide oflessreactivemetal

Lessreactivemetal

77

Extraction of metals



Extraction of metalsMetal Extraction method

Potassium

Electrolysis

Sodium

Calcium

Magnesium

Aluminium

Carbon

Zinc

By heating the ore with carbon

in a furnace

Iron

Tin

LeadCopper Heating the ore alone

Mercury

Silver Exist in metal form

Gold 78

EXTRACTION OF TIN FROM TIN ORE (CASSITERITE)



1400 o C

1000 o C

400oC

200 o C

Slag is used as

road surfaces

Sulphur + arsenic

Sulphur dioxide + arsenic oxide

Tin ore + carbon

Tin +Carbon dioxide

Blast furnace

Liquid tin is collected

at bottom of furnace

Hot air

limestone

79



All the best!!!!!!!

80

INSTRUCTION

http://g/BENGKEL%20KURIKULUM/Funny/Funny/f18vsf1.mpeg



1 Teacher introduces the topic with the aid of Diagram 1.

2 Students find the definition of every terminology involved

with the aid of guided worksheet 1.

3 Teacher explains one example of electrolysis of molten

lead(II) bromide. (Refer slide 5)

4 Based on the example above, students try out electrolysis of

molten copper(II)chloride.(Refer slide 6)

5 Students in each group collect and gather information aboutthe uses of electrolysis by using text book or reference book.

(Refer slide 8 – 13)

6 Teacher facilitates students and discusses answers.

7 Students are tested verbally on the learning outcomes.(Refer slide14-19)

8 Students in each group develop a mind map, starts with the

main ideas of electrolysis. (Refer slide 20)

9 At the end of the lesson, students do the self test.

(Refer slide 21 -23)81



82



83



84



85



5.5. UNDERSTANDING

ELECTROLYSIS

86



1 State what electrolysis is

2 State what anode, cathode, anion, cation and

electrolyte are

3 Describe the electrolysis of an electrolyteusing carbon electrodes

4 Explain the uses of electrolysis in industry

5.5. UNDERSTANDING ELECTROLYSIS

87

5.5 ELECTROLYSIS



A

anion

CathodeAnode

Cation

Electrolyte

Rheostat

Ammeter

Switch

Diagram 1

88

Worksheet 1



•Electrolysis

•Electrolyte

•Electrodes

•Cathode

• Anode

•Cations

• Anions

Process of .................................... of substance using .....................

Substance that ........................... when …………… passes through.

Substance that allow electricity to.................. or ..................

an electrolyte.

The ............................... electrode

The ................................. electrode

.......................... charged ions

........................... charged ions

Meaning of Electrolysis

decomposition electricity

decomposes electricity

enter leave

negative

positive

negatively

positively

Electrical energy ……………… ?

89

The Experiment



The Experiment

Electrolysis of molten lead (II) bromide

Lead

Bromine

90



91



92

2. Electrolysis of molten lead (II) bromide

Anode Cathode

http://g/PPK%202009%20EDITED%20Sains%20Teras%20Men%20Atas/Makan%20Biskut.wmv



Anode Cathode

The .............................. charged

..................... ions move to the anode

The .............................. charged

..................... ions move to thecathode

....................... ions release

.......................... to the anode and form

...............................molecules

................... ions receive

.........................from the cathode and

become ........................ atom.

............. ion + .............

................molecules

................. + electron

…........atom

............. bromine atoms form one

bromine molecule

Lead metal is ............................. on

the ...................

negat ively

bromide

posi t ive ly

lead

Bromide

electrons

bromine

Lead

electrons

lead

Bromide

bromine

electron Lead ion

Lead

Two deposi ted

cathode

93

2. Electrolysis of molten copper (II) chloride

Anode Cathode



Anode Cathode

The .............................. charged

..................... ions move to the anode

The .............................. charged

..................... ions move to thecathode

....................... ions release

.......................... into the anode and

form ...............................molecules

................... ions receive

.........................from the cathode and

turn into ........................ atom.

............. ion + ..............

...............molecules

..................... + electron

…............. atom

............. chlorine atoms form one

chlorine molecule

Copper metal is .............................

on the ...................

negat ively

chlor ide

posi t ive ly

copper

Chlor ide

electrons

chlor ine

Copper

electrons

copper

chlor ide

chlor ide

elect ron copp er ion

copper

Two deposi ted

cathode

94



95

USES OF ELECTROLYSIS IN INDUSTRY

http://localhost/var/www/CURRICULUM/PANITIA%20SAINS/STAF%20PROFESIONAL%20DEVELOPMENT/COURSE%20MATERIALS/PPKMANDARINKL/Funny/KatakRempit.mpg



A. Electroplating

Objects made of iron .................. easily when exposed to air.

To ........................... iron objects from corrosion, they are……………

with a thin layer of non reactive metal such as copper.

The aims of electroplating are to make objects more .......................

and .................. to corrosion.

corrode

prevent coated

attractive

resistant

Click for

experiment

96

• The figure shows an iron spoon being

electroplated with copper .

http://g/PPK%202009%20EDITED%20Sains%20Teras%20Men%20Atas/Electroplating.flv






A

p pp

i) An iron spoon is used as the ........................

ii) Copper is used as the ..............

iii) The electrolyte is a solution of ......................

compound

• At the anode :

The copper dissolves forming

............................charged copper ions.

• At the cathode:

The .................... ions receive electrons,

forming a coat of ...................... on iron spoon.

• A rheostat is used to control the current flow in

the circuit so that a ..................... and steady

current is used. This is to ensure that the coating

is .......................... and ......................

Copper

as anode

Iron sp oon

Copper s ulphate

so lu t ion

cathode

anode

copper

posi t ive ly

copper

copper

smal l

f i rm even

97



NON-REACTIVE METALS SUCH AS

COPPER , SILVER AND GOLD

ARE FOUND AS FREE ELEMENTS.

THESE METALS

CONTAIN IMPURITIES AND CAN BE

PURIFIED BY ELECTROLYSIS

98

THE IMPURE METAL IS THE ANODE



THE PURE METAL OF THE SAME TYPE IS

THE CATHODE

THE ELECTROLYTE IS THE METAL SALT SOLUTION

CONSISTING OF METALLIC IONS WHICH

IS TO BE PURIFIED

IN THE PURIFICATION OF COPPER;

The impure copper is used as anodeThe pure copper is used as cathode

The electrolyte is copper sulphate solution99



100



101



102



103



104



105



106



107



108



109



110



111





113

http://g/PPK%202009%20EDITED%20Sains%20Teras%20Men%20Atas/Main.ppt



B. Extraction of metals

d b



Oxygen g ases

Molten

a lumin ium

anode carbon

Cathode

carbon

Baux ite +

cryol i te

115

At th th d

B. Extraction of metals



Electrolysis is a process to extract metals

such as sodium, ...................... and

aluminium which are more ....................

than carbon.

Aluminium is extracted through

electrolysis from molten

..............................

At the cathode

i) The positively charged .......................

ions are attracted to the cathode.

ii) Aluminium ions receive electrons

and become aluminium ......................

At the anode:

i) The negatively charged

..................... ions are attracted to the

anode.

ii) Oxide ions release electrons to

become ................... atoms

iii) The oxygen atom pairs together to form

… ............ gas

magnes ium

bauxite

reactive

a lumin ium

atoms

oxide

oxygen

oxygen

DIAGRAM

116

A C. Purification of metals



A

Mass of anode

.................. Mass of

cathode

.................Impuri t ies

decreases

increases

Copper

sulphate

so lu t ion

Anode(impu re cop per)

Cathode

( Pure copper)

117

The diagram shows how electrolysis is used to purify copper



• The anode is made of ……………………..

• The cathode is made of ……………………..

• The electrolyte used is ………………………..

• When electricity is passed through the electrolyte:

i) The copper anode dissolves to form …………. ions

ii) The positively charged copper ions are attracted to

the ………………………

iii) Copper ions receive electrons from the …………….

and form copper atoms which are deposited on the

…………………

iv) At the same time the …………………… settle to the bottom

impu re copp er

pure copper

copper sulphate solut ion

copper

cathode

cathode

cathode

impur i t ies

118



119

http://g/PPK%202009%20EDITED%20Sains%20Teras%20Men%20Atas/twisted_head.wmv



DISCUSSION

120



121



122



123

**TASK 1



Label the diagram above. 124

**TASK 2



Choose the correct answer. 125

**TASK 3



DRAW YOUR OWN MIND MAP !!!

* MAIN IDEA:

“USES OF ELECTROLYSIS” 126

ELECTROLYSIS is a process of breaking down chemical substances in aqueous

solution or molten state to its constituents by using …………………..



Electrical energy ……….......... energy

G …………….

EXAMPLE:

Aluminium ion + electrons Aluminium atom

Oxide ion Oxygen atom + electron

(At cathode):

(At anode): 127

(molten aluminium oxide)

ELECTROPLATING IRON NAIL WITH COPPER



Name of process : ……………………………..

Metal M: ……………………………………...

Electrolyte,N: ………………………………..

ANODE: ………………… CATHODE: …………………….

Metal becomes

……………..

Iron nail is coated

with …………….. layer.

**To obtain a good quality:

1. Dilute ……………… should be used.

2 Use …………….. electric current.

128





130



131



132



133



5.6 Understanding the production

of electrical energy from chemicalreactions

134

Learning Objectives



Learning Objectives

5.6 Understanding the production of

electrical energy from chemical reactions.

Learning Outcomes A student is able to :

i) Describe how a simple cell works

ii) List the various types of cells and theiruses

iii) State the advantages of and

disadvantages of various types of cells

135



SIMPLE CELL

• Electrochemical

cell 1

136

THE PRODUCTION OF ELECTRICAL ENERGY BY A

SIMPLE CELL

http://g/PPK%202009%20EDITED%20Sains%20Teras%20Men%20Atas/Link%20Folder/content%202/l70conp2.swf






Zinc

plate

G

........................................................

................

........................Copper

plate

A simple cell consists of two

....................... and an...........................

Two electrodes made of two different

...............

The electrolyte can be a ..........................,

....................... or ...............................

The diagram shows a simple cell circuit.

In the cell,

i) .................... and copper plates are usedas .....................

ii) ................ is more reactive than copper

iii) The electrolyte used is ..............................

electrodes electrolyte

sal t solut ion

di lu te acid

metals

di lu te alkal i

Z inc

electrodes

Zinc

co pp er (II) su lph ate

so lu t ion

copper (II) sulp hate solut io n

Cont 4

Cont

137

EXERCISE 1• In a simple cell, the more reactive metal acts as the







In a simple cell, the more reactive metal acts as the......................... terminal which gives out electron and theless reactive metals acts as the ...................... terminal.

• In this process, the zinc plate is the ................... electrodeand the copper plate is the ...................... electrode.

• The .................. from the zinc atoms flow to the copperelectrode through the connecting wire. Thus the ..................electrode dissolves in the electrolyte.

• At the copper electrode , ........................ ion from the

electrolyte receives the electrons.

• The flow of electron from ..................electrode to ...............electrode through the connecting wire deflect thegalvanometer. This proves that the process produces

energy

negat ive

posi t ive

zinc

electrons

hydrogen

posi t ivenegat ive

electr ical

posi t ive

negat ive

138

CELL AND THEIR USAGE Type of cells Uses Advantages Disadvantages

Dry cells

Transistor radio Light Non-rechargeable

N l l i

http://f/SAINS%20PPK%2008/5.6/Grandma.mpg



Dry cells ..............................

...

..............................

....

..............................

.....

............................

............................

..............................

..............................

............................

............................

..............................

Wet cells ..............................

....

......................................

.....

......................................

......

......................................

......

............................

............................

..............................

..............................

Alkaline

batteries

..............................

....

……………………

….

……………………

......................................

...

......................................

...

......................................

...................................

..

Remote contro l

A larm c lock

Small

Portable

Cheap

Not long last ing

Leakage may happen

Used in vehic les

Rechargeable

High vo l tage

Long- last ing

Heavy

Expensive

Ac id m ight sp i l l

Dist i l led water need to

be addedRadios

Torchl ights

Toys

Large current

Long- last ing

Constant vo l tage

Watches,

Calculators,

Hearing aids

Cameras

Non-rechargeable

Small , long-last ing

Portable

Steady voltage

Constant current

Non-rechargeable

Expensive

ExpensiveRechargeable

Long- last ing

Use in electronic

devices such as

d i i tal camera

ADV 5

139






GOOD LUCK

140

http://g/PPK%202009%20EDITED%20Sains%20Teras%20Men%20Atas/Link%20Folder/TNB%20main.gif



141



142





144



145



5.7 LIGHT AND

CHEMICALREACTIONS

CLICK

HERE 146

LE RNING RE

ENERGY AND CHEMICAL CHANGES

http://g/PPK%202009%20EDITED%20Sains%20Teras%20Men%20Atas/mouse.asf







LE RNING OBJECTIVES

1.7 Understanding chemical reactions that

occur in the presence of light

LE RNING OUTCOMES

A student is able to•give examples of chemical reactions which

require light,

•explain the effect of light on photosensitive

chemicals,•explain why certain chemicals are stored in

dark bottles.

147

INSTRUCTIONS:

1.Teacher distributes mahjung paper, marker

d W k h t 1



pen and Worksheet 1.

2.Teacher groups the students and asksthem to make a Mind Map. Then answer the

questions in Worksheet 1 (Time given : 30

minutes)

3.Teacher facilitates students in their work.4.Teacher will discuss the mind map the

students have done.

5.Teacher will use this power point and the

teaching courseware from PPK duringdiscussion.

148

MIND MAP



Light and ChemicalReactions

Chemical Changes Caused

by Light EnergyLight Energy and

Photographic Film

Storing Photosensitive

Chemicals

CLICK

HERE 149

Examples of photosensitive chemicals

http://g/PPK%202009%20EDITED%20Sains%20Teras%20Men%20Atas/AWIMAWEB%201.wmv






• Examples of photosensitive chemicals

Silverbromide

Silverchloride

Hydrogenperoxide

150

Photosensitive Chemicals

Some chemicals are to light

sensi t ive



Some chemicals are .................. to light .

The chemicals will ................... when ........................ to light.

Examples of photosensitive chemicals are .................................... and

............................................

The chemicals cannot be .................. in a glass bottle.

Hydrogen peroxide .................. + ...........

In the presence of ......................... ,hydrogen peroxide ...................... into

..................... and ..............

Silver chloride ...................... + ...............

Silver chloride decomposes into ........................... and ..........................The chemicals are stored in an ..................... glass bottle.

decompose exposed

hydrogen perox ide

si lver n i t rate

stored

water oxygen

l ight

si lver

decomposes

water oxygen

ch lor ine

si lver ch lor ine

opaque

151

Photosynthesis

Water and

mineral sal ts

are absorb ed

Instructions : Students are asked to answer the questions inWorksheet 2 after discussion.



................................ + .................................. ............................ + .............................

During photosynthesis, ...................

(green pigment) absorbs ..........................

The energy is used to ............. the .

..................... molecules into

....................... and .......................

.........................is released into the

...............................

The ........................ atoms reacts with

carbon dioxide to form .........................

.................Oxygen is

released into the

air

l ight energy

Carbon dioxide

is abso rbedf rom the air

Glucose

is sent

to the

whole

plant

are absorb ed

from the soi l

by the roots

Water Carbon dioxid e Glucose Oxygen sun l igh t

Chlorophy l l

ch lorophy l l

l ight energy

spl i t

water

hydrogen oxygen

Oxygen

air

hydrogen

glucose

152

PHOTOSYNTHESIS

carbon



……………

+ ……………. …………….

+ ……………….

chlorophyllcarbon

dioxide oxygen glucose water

…………………

…………………………. Sunlight

153

carbon

dioxide water oxygen glucose

LEARNING OUTCOMES

A student is able to;

explain the effect of light on photosensitive chemicals



• explain the effect of light on photosensitive chemicals,

• explain why certain chemicals are stored in dark bottles.

Instruction: Teacher directs the students to carry out the group

activity.

Aim : To study the effect of light on chemical reactions

1 Students carry out an activity in groups to study the

effect of light on photographic paper

2 Teacher distributes a piece of photographic paper to

each group.

3. Students place a leaf on the photographic paper and

put it in the sunlight.4. After 10 minutes, students record their observations.

5. Students discuss the effect of light on photographic

paper and present their findings.

154

f O

Observation



Part of photographic paper Observation

Covered with leaf

Exposed to light

Analysis

1. What inference can be made from your observation?

2. Write a word equation for the reaction of silver bromide with light.

155



Photographic paper

Instructions : Students are asked to answer questions in

Worksheet 3 after discussion.



Silver bromide ...................... + ...............

(Grey)

Photographic paper is coated with ......................... .

When ............... falls on the paper, silver bromide is

.......................... into ........................... and ....................... .

The formation of .................... atoms on the photographic

paper causes....................... black areas on the paper.

Bromine

Photographic paper

s i lver brom ide

decomposed

l ight

si lver

bromine si lver

greyish

Silver

157

Storage of

chemical



c e ca

substances

The chemicals are stored in

opaque containers or dark

coloured bottles.

CLICK

HERE 158

http://g/PPK%202009%20EDITED%20Sains%20Teras%20Men%20Atas/jurassic_fart.wmv







159



160



161



162



163



5.8 THE BENEFITS OF

CHEMICALREACTIONS

164

LEARNING AREA : ENERGY



AND CHEMICAL CHANGES

5.8 Appreciating the innovative

efforts in the design of

equipment using chemical

reactions as sources of energy

165

LEARNING OUTCOMES





- describe how energy obtained from chemical

reactions should be used efficiently to prevent

wastage

- describe how equipment utilising chemical reactions

as sources of energy should be disposed to reduceenvironmental pollution

- give suggestions on new ways of using chemical

reactions as sources of energy for equipment

- put into practice good habits when using anddisposing equipment that uses chemical reaction as

a source of energy166

CONTENT OF THESE LEARNING OUTCOMES

- equipments using chemical reactions



- efficient use to prevent wastage

- proper disposal- alternative sources of energy

- use energy saving electrical appliances

- iron all the clothes at one time- turn off all electrical appliances when not in

use

- use fluorescent lamps instead of bulbs- close refrigerator door as soon as possible

- (other possible answers)167

Group Work : Students do a



mind map on the innovativeefforts in the design of

equipment using chemicalreactions as sources of energy

linking all the learning

outcomes.

168

Students can obtain theinformation from websites,



,

books, magazines, journals ornewspapers.

(Note : An example is shownbelow)

#Slides 13,14,15 are motivational slides, to be

used when needed.169

Mind map Equipments

using



Efficient useto prevent

wastage

ProperDisposal

Alternative

sources of

energy

us g

chemical

reactions

# continue next

slide

170

Efficient use to



Use energy

saving

electrical

appliances

Iron all theclothes at

one time

Turn offelectrical

appliances

when not in use

prevent

wastage

171

Proper

Used

batteries



Disposal

172

Alternative

sources of



sources of

energy

173

SELF TEST1. Cellular phones use …………….

batteries.



batteries.

2. Name two appliances that useelectrical energy.

3. Name the gas produced from the

burning of fossil fuels that can cause acidrain.

4. Name a way you can help to conserve

electricity in your home.

5. What happens when toxic substancesare not disposed off properly?

174

Answers to Self Test



Answers to Self Test1. rechargeable2. toaster, computer, television

3. sulphur dioxide

4. Turn off the lights when not in use.5. Toxic substances if not disposed off

properly will cause environmental

pollution.

175



Education isnot preparation

for life;education is lifeitself.

176

http://www.wisdomquotes.com/000603.html



MARIA MITCHELL: Study as if you

were going to live

forever; live as if

you were going to

die tomorrow..

177

• FRANCIS BACON:

• We cannot command nature







except by obeying her.

• LINDA HOGAN: • There is a way that nature

speaks, that land speaks. Most of

the time we are simply not patientenough, quiet enough, to pay

tt ti t th t

178





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