Chemistry Investigatory Project on Evaporation of Liquid

8/17/2019 Chemistry Investigatory Project on Evaporation of Liquid

1/22

KENDRIYA VIDYALAYA

JANAKPURI

SESSION : 2016-17

INVESTIGATORY PROJECT-

EVAPORATION OF LIQUID

Name : DIVYANSU

R!"" N!# : 17

C"a$$ : %II

Se&'(!) : A


2/22

CERTIFICATE

This is to certify that Divyanshu of

Class XII ‘A’ has satisfactorily completed the

project on “ EVAPORATION OF LIQUID” under

the guidance of M!"#M $%MA& "'T(

Chemistry during the session)*+,(+-!

"lace. $!/!0ana1puri "#M $%MA

Date. "'T(Chemistry


3/22

ACKNO*LEDGE+ENT

I2d li1e to e3press my greatest gratitude to the people 4ho have helped 5supported me

throughout my project! I’ m grateful to +R#

PRE+ KU+AR, PGT-Cem($'./ for his

continuous support for the project& from initial

advice 5 encouragement to this day!

6pecial than1s of mine goes to my colleague

4ho helped me in completing the project 7y

giving interesting ideas& thoughts 5 made this

project easy and accurate!I 4ish to than1s my parents for their

undivided support 5 interest 4ho inspired me

5 encouraged me to go my o4n 4ay& 4ithout

4hich I 4ould 7e una7le to complete my

project! At last 7ut not the least I 4ant to

than1s my friends 4ho appreciated me for my

4or1 5 motivated me and finally to 'od 4ho

made all the things possi7le!!!


4/22

CONTENTS

6! no! Contents "age 8o!

+ I8T9D%CTI98 +

) AIM :; A""AAT%6 <

: MAT#IA= #>%I#D ,

< T?#9@ -

, "9C#D%# +;

- "?9T9'A"? +<

9B6#/ATI98 +,

C98C=%6I98 +-

+* BIB=I9'A"?@ +


5/22

INTRODUCTION

#vaporation is the process 4here7y atoms

or molecules in a liuid state Eor solid state

if the su7stance su7limesF gain sufficient

energy to enter the gaseous state!

The thermal motion of a molecule must 7e

sufficient to overcome the surface tension

of the liuid in order for it to evaporate&

that is& its 1inetic energy must e3ceed the

4or1 function of cohesion at the surface!

#vaporation therefore proceeds more


6/22

uic1ly at higher temperature and in

liuids 4ith lo4er surface tension! 6ince

only a small proportion of the molecules

are located near the surface and are

moving in the proper direction to escape at

any given instant& the rate of evaporation is

limited! Also& as the faster(moving

molecules escape& the remaining molecules

have lo4er average 1inetic energy& and the

temperature of the liuid thus decreases!

If the evaporation ta1es place in a closed

vessel& the escaping molecules accumulate

as a vapor a7ove the liuid! Many of the

molecules return to the liuid& 4ith

returning molecules 7ecoming more

freuent as the density and pressure of the

vapor increases! Ghen the process of


7/22

escape and return reaches euili7rium& the

vapor is said to 7e Hsaturated&H and no

further change in either vapor pressure and

density or liuid temperature 4ill occur!


8/22

Aim

To compare the rate of evaporation of

various liuids!

Apparatus


9/22

1. China dish

2. "ipette E +* ml F

# Geighing machine

Materials Required


10/22

+! ; different liuid samples

EAcetone&Gater&Diethyl ether are ta1en

hereF

Theory

Factors influencing rate of evaporation:-


11/22

+! Concentration of the su7stance

evaporating in the air! If the air already has

a high concentration of the su7stance

evaporating& then the given su7stance 4ill

evaporate more slo4ly!

)! Concentration of other su7stances in the

air! If the air is already saturated 4ith other

su7stances& it can have a lo4er capacity for

the su7stance evaporating!

;! Temperature of the su7stance! If the

su7stance is hotter& then evaporation 4ill

7e faster!

:! lo4 rate of air! This is in part related to

the concentration points a7ove! If fresh airis moving over the su7stance all the time&

then the concentration of the su7stance in


12/22

the air is less li1ely to go up 4ith time&

thus encouraging faster evaporation! In

addition& molecules in motion have more

energy than those at rest& and so the

stronger the flo4 of air& the greater the

evaporating po4er of the air molecules!

forces 1eeping the molecules together in

the liuid or solid state the more energy

that must 7e input in order to evaporate

them!

6# S.a&e a.ea a)3 'em4e.a'.e:

-Because molecules or atoms evaporate

from a liuid’6 surface& a larger surface

area allo4s more molecules or atoms to

leave the liuid& and evaporation occurs

more uic1ly! or e3ample& the same


13/22

amount of 4ater 4ill evaporate faster if

spilled on a ta7le than if it is left in a cup!

?igher temperatures also increase the rate

of evaporation! At higher temperatures&

molecules or atoms have a higher average

speed& and more particles are a7le to 7rea1

free of the liuid’6 surface! or e3ample& a

4et street 4ill dry faster in the hot sun

than in the shade!

ntermolecular forces: -

Most liuids are made up of molecules&

and the levels of mutual attraction among

different molecules help e3plain 4hy some


14/22

liuids evaporate faster than others!

Attractions 7et4een molecules arise

7ecause molecules typically have regions

that carry a slight negative charge& and

other regions that carry a slight positive

charge! These regions of electric charge are

created 7ecause some atoms in the

molecule are often more electronegative

Eelectron(attractingF than others! The

o3ygen atom in a 4ater E?)9F molecule is

more electronegative than the hydrogenatoms& for e3ample& ena7ling the o3ygen

atom to pull electrons a4ay from 7oth

hydrogen atoms! As a result& the o3ygen

atom in the 4ater molecule carries a partialnegative charge& 4hile the hydrogen atoms

carry a partial positive charge! Gater


15/22

molecules share a mutual attractionJ

positively charged hydrogen atoms in one

4ater molecule attract negatively charged

o3ygen atoms in near7y 4ater molecules!

Intermolecular attractions affect the rate of

evaporation of a liuid 7ecause strong

intermolecular attractions hold the

molecules in a liuid together more tightly!

As a result& liuids 4ith strong

intermolecular attractions evaporate more

slo4ly than liuids 4ith 4ea1intermolecular attractions! or e3ample&

7ecause 4ater molecules have stronger

mutual attractions than gasoline molecules

Ethe electric charges are more evenlydistri7uted in gasoline moleculesF&


16/22

gasoline evaporates more uic1ly than

4ater!

!rocedure


17/22

+! Ta1e three china dishes!

)! "ipette out +* ml of each sample!

;! Dish A( Acetone

Dish B( Gater

Dish C( Diethyl ether

:! ecord the 4eights 7efore 7eginning the

e3periment!

an hr and 4ait patiently!


18/22

,! ecord the 4eights of the samples

after the given time!

-! Compare the prior and present

o7servations!


19/22

!hotograph


20/22

"#servation

Amount of each liuid sample ta1enL+*ml

Gater

EgmF

Acetone

EgmF

Dieth

ethe

Egm

Geight of dish

Geight of

Edishsu7stanceF

7efore evaporation

Geight of

Edishsu7stanceF

after evaporation

Geight of su7stanceevaporated

$onclusions


21/22

The rate of evaporation of the given threeliuids is in order .(

Diethyl #therNAcetoneNGater

7ecause Gater has e3tensive hydrogen 7onding in 7et4een o3ygen atom of one

molecule and hydrogen atom of another

molecule! But this is a7sent in the case of

Acetone!


22/22

%%&"'RA!()

https.OOen!4i1ipedia!orgO4i1iO#vaporation

http.OO444!encyclopedia!comOtopicOevapor

ation!asp3

https.OOcommons!4i1imedia!orgO4i1iOCate

gory.MeasuringPinstrumentsPEevaporation

F
https://en.wikipedia.org/wiki/Evaporationhttp://www.encyclopedia.com/topic/evaporation.aspxhttp://www.encyclopedia.com/topic/evaporation.aspxhttps://commons.wikimedia.org/wiki/Category:Measuring_instruments_(evaporation)https://commons.wikimedia.org/wiki/Category:Measuring_instruments_(evaporation)https://commons.wikimedia.org/wiki/Category:Measuring_instruments_(evaporation)http://www.encyclopedia.com/topic/evaporation.aspxhttp://www.encyclopedia.com/topic/evaporation.aspxhttps://commons.wikimedia.org/wiki/Category:Measuring_instruments_(evaporation)https://commons.wikimedia.org/wiki/Category:Measuring_instruments_(evaporation)https://commons.wikimedia.org/wiki/Category:Measuring_instruments_(evaporation)https://en.wikipedia.org/wiki/Evaporation

Chemistry Investigatory Project on Evaporation of Liquid

Documents

Transcript of Chemistry Investigatory Project on Evaporation of Liquid