C5_WATER & SOLUTION/FORM2

8/14/2019 C5_WATER & SOLUTION/FORM2

1/60

2013/11/13

CHAPTER 5: WATER AND

SOLUTION
http://www.wpclipart.com/weather/water_drop.pnghttp://www.wpclipart.com/weather/water_drop.png


2/60

2013/11/13

Physical Characteristicsof Water

Pure water colorless ,odorless & Tasteless

Can exist in three states;i) solid ii) Liquid iii) GasConsist of many tiny particlescalled water molecules (KineticTheory)


3/60

2013/11/13

The changes of states of water


4/60

2013/11/13

Freezing point of Water

The temperature at whichwater freezes into ice.

Freezing point 0oC

The temperature isconstant at 0 oC throughoutthe freezing point


5/60

2013/11/13

Determining the freezing point ofwater


6/60

2013/11/13

Cooling graph of water


7/60

2013/11/13

Boiling point of water

The temperature at whichwater boils and becomes

steamBoiling point 100 0C

The temperature isconstant at 100 0C .


8/60

2013/11/13

Determining the boiling point ofwater Thermometer

Flat-bottomed flask

100cm 3 of distilledwater

Glass tube


9/60

2013/11/13

Heating graph of water


10/60

2013/11/13

Physical

characteristicsof water

Expand uponfreezing

Freezing point is 0 o C Boiling point is 100 o C

Poor electricalconductor

Odorless, colorless,tasteless

Has density of 1g

per cm3

at 4o C

Poor thermalconductor


11/60

2013/11/13

Effects of impurities in water

Impurities in water can change thephysical characteristics of water .Examples; Sea water

- Tastes salty (dissolved saltsin it)

- Lower freezing point- Higher boiling point

- High density


12/60

2013/11/13

Composition of Water

Water is a compound whichis made up of the elements

hydrogen & oxygenEach water molecule has 2

hydrogen atoms bound toone oxygen atom


13/60

2013/11/13

Model of water molecule


14/60

2013/11/13

Questions

1. States the physical characteristics of watera) colour ___________________

b) Smell

___________________c) Taste ___________________d) Density- ___________________

e) Freezing point- ______________f) Boiling point - _______________


15/60

2013/11/13

2. Water exists in three states whichare ______, __________ and

__________.

3.Water is a _______ made up of one

atom of oxygen and two atoms of __________.

4. Impurities in water cause the

boiling point of water to___________and the freezing point of waterto________


16/60

2013/11/13

ElectrolysisTo determine thecomposition of water

Electric current is passedthrough water so that water

break down into hydrogengas and oxygen gas


17/60

2013/11/13

A B


18/60

2013/11/13

Observation

Measuringcylinder

A B

Volume of gasafter 5

minutes (cm 3)

8.0 4.0

Test for gas The gasexplode witha pop sound

The gasrelight theglowingsplinter


19/60

2013/11/13

DiscussionThe gas collected in A explode with pop sound shows the presence ofhydrogenHydrogen released at the negativeelectrode (cathode )The gas collected in B relight theglowing splinter shows the presence ofoxygenOxygen gas released at the positive

electrode (Anode )


20/60

2013/11/13

Conclusion

The ratio of the volume ofthe oxygen gas to hydrogen

gas is 1:2A molecule of water is made

up of one atom of oxygen and two atoms of hydrogen


21/60

2013/11/13

Evaporation of Water

Process by which a liquid

changes into its vaporEvaporation can occur at

any temperature


22/60

2013/11/13

Model showing the

evaporation of water

Water


23/60

2013/11/13

The rate of evaporation of

water is affected bythe following factors;

The HumidityThe temperature of thesurrounding

The surface area of the waterThe movement of air (wind)


24/60

2013/11/13

Evaporation&

Boiling


25/60


26/60

2013/11/13

Differences betweenEvaporation & Boiling

Evaporation Aspect BoilingOn the

surface of theliquid

Site of

process

Throughoutthe liquid

Occurs at alltemperaturebelow 100 oc

Temperature Occurs at the100 oc

A slow process Rate A fast process


27/60

2013/11/13

APPLICATION OF

EVAPORATIONOF WATER IN

DAILY LIFE

DRYINGCLOTHES

DRYING HAIR

PRESERVATION OFAGRICULTURAL PRODUCT

PROCESSING OFFOOD


28/60

2013/11/13

SOLUTION AND

SOLUBILITY


29/60

2013/11/13

Solution

Exist all around usExamples Oceans, rivers &minerals waterThe dissolved substance iscalled the solute.

The substance that dissolvesthe solute is called thesolvent.


30/60

2013/11/13

Solute Solution

D i s s o l v e s i n a s o l v e n t


31/60

2013/11/13

DILUTE,CONCENTRATED

AND SATURATED

SOLUTION


32/60

2013/11/13

DILUTE SOLUTION Has very little solute Can dissolve a lot more solute

CONCENTRATED SOLUTION Has a lot of solute in it Can dissolved a little more solute

SATURATED SOLUTION Has the maximum solute Cannot dissolve any more solute


33/60

2013/11/13

Solution and Suspension

SolutionTransparent and clearMaybe colorless orcolored

HomogeneousE.g. salt solution


34/60

2013/11/13

Suspension

Has a lot of suspendedparticlesAppears cloudyNon-homogeneous

orheterogeneousE.g. muddy water


35/60

2013/11/13

SolubilityThe solubility of solutedepends on the

a) nature of the solventb) nature of the solutec) temperature


36/60


37/60


38/60

2013/11/13

Water as Solvent

Water is known as the universal solvent

Organic SolventOrganic compoundscontaining carbon that used

to dissolves solutesExp; alcohol, turpentine,acetone


39/60

2013/11/13

Acid

&

Alkali


40/60

2013/11/13

Acids

The word acid comes from theLatin word acidus which meanssour.

Food containing Acid


41/60

2013/11/13

Food Acid in FoodGrapes Tartaric acid

Apples Malic acid

Oranges, lemons Citric acidTomatoes Salicylic acid

Vinegar Acetic acid(ethanoic acid)

Yoghurt drinks Lactic acid


42/60

2013/11/13

PROPERTIES OFACIDS

Sour Test

PH valuesless than 7

Corrosive

React with

metal

Turns blue litmuspaper to red


43/60

2013/11/13

ALKALI

Often used in many

household cleanerssuch as in bath, sink

and glass cleaners


44/60

2013/11/13

Properties of alkaliHas bitter tasteHas a soapy feelHas a pH greater than 7Has corrosive natureTurns red litmus paper toblue


45/60

2013/11/13

PH Scale


46/60

2013/11/13

NEUTRALISATIONChemical reaction in which anacid and alkali react to form a

salt and water .

To neutralize an acid or alkali completely, we use a methodcalled Titration.

Acid + Alkali Salt + Water


47/60

2013/11/13

Titration


48/60

2013/11/13

WATER PURIFICATION

Water can be purifiedeither by

a) Boilingb) Chlorination

c) Filtrationd) Distillation


49/60

2013/11/13

a) BoilingHigh temperature duringboiling kills of themicroorganism.Used to make water safefor drinking at homeHowever, boiling does notremove suspended

particles


50/60

2013/11/13

b) Chlorination Chlorine is added towater.

The chlorine kills micro-organisms in the water.

Chlorination is used totreat the water inswimming pools.


51/60

2013/11/13

c) Filtration

Method involvespassing waterthrough a filter toremove suspendedparticles.


52/60

2013/11/13FILTRATION


53/60

2013/11/13

Water Purification Equipment


54/60

2013/11/13

d) DistillationTo obtained pure water.Does not contain anydissolved substances.Free from anysuspended solid &micro-organism.


55/60

2013/11/13

DISTILLATION


56/60

2013/11/13

WATER SUPPLY SYSTEM

Usage ofwater

Direct or in-streamuse

Domesticuse

Agricultural use Industrialuse


57/60

2013/11/13

WATER TREATMENT

PLANTRaw water for thewater supply isobtained from stream ,rivers and rainwater .


58/60

2013/11/13


59/60

2013/11/13

Water Treatment Process


60/60

Conservation &

Preservation of waterCleaning up polluted river

Proper disposal of wastePromoting public

awarenessLaws

Documents

C5_WATER & SOLUTION/FORM2