2nd Day Handout

8/9/2019 2nd Day Handout

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omposition of Matter

Louie Paolo D. CarpioInstructor 3

Institute of Chemistry, UP Diliman


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OBJECTIVES for today

1. Definition of an atom

2. Development of the atomic model

3. Sub-atomic particles

4. Isotopes and the averae atomic

mass


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SI!!S you "ill #e learnin$

1. Identif!in the number of protons"electrons and neutrons for

different elements and ions

2. Calculation of mass number

3. Calculation of the averae atomic

mass


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%tom& Definition

%tom' smallest (article of an element

Picture of )i*+o& each dot

re(resents an atom usin$ anion field micro$ra(h


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Daltons %tomic Theory%tomic -y(othesis in ./01

.2 all matter is com(osed #y atoms

2 atoms are indestructi#le and unchan$ea#le

32 elements are made u( of the same atoms

*2 elements com#ine in sim(le "hole num#erratios

42 a chemical reaction in5ol5es rearran$ementof atoms


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Su#atomic Particles

Su#atomic (articles of im(ortance to Chemistry&

2 proton' (ositi5ely char$ed

32 electron' ne$ati5ely char$ed

*2 neutron6 unchar$ed

7 Protons 8 neutrons 9 nucleons

Chemical reactions : electrons are in5ol5ed

)uclear reaction : nucleons are in5ol5ed


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Com(arison of su#atomic (articles


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Disco5ery of Electrons

;Based on the e


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;he concluded thatcathode rays arestream of neativechares"hich

came from theatoms;the char$ed(articles "ere the

same re$ardless ofthe metal he usedfor the electrode

#oseph #ohn$homson


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;%obert &illi'an"as a#le tocom(ute the chare of the

electron#ased on his oil6dro( e


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Based on thee0 < .06.?C

;mass of the electron 9

?2. < .063.$


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Disco5ery of Protons

;Based on the e usin$ $as dischar$etu#es that had (erforated

cathodes;he o#ser5ed that differentelements $i5e differentchar$e to mass ratios


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Plum6(uddin$ model of an atom

;De5elo(ed #y #.#.$homsonin .?0*

;S(here of (ositi5echar$e "here ne$ati5echar$es are em#edded


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Disco5ery of )ucleus;Based on the e


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Disco5ery of neutrons

;mass of elements "ereal"ays hi$her than themass com(uted fromaddin$ electrons and

(rotons;#ames Chad*ic'disco5ered a (article "iththe same mass of a (roton

#ut "ith no electricalchar$e


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%tomic )um#ers

;determined #y +enr!&osele!usin$ cathoderays

;different elements#om#arded "ith cathoderays emit


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)uclear +odel of an %tom

proton' (ositi5ely char$edelectron' ne$ati5ely char$edneutron6 unchar$ed

,tomic number /9num#er of (rotons

&ass number ,/9

num#er of (rotons 8num#er of neutrons


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e(resentin$ )eutral Elements

12

6C

&ass number@%A

,tomic number@A

0 number of protons 0

, 0 of protons/ of neutrons/ 0 12

umber of neutrons 0

5elo* is Carbon 6 12


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12

6

C&ass number@%A

,tomic number@A

0 number of protons 0

$he atomic number / is uni7ue for

each element, chan$in$ the atomicnum#er "ould mean chan$in$ the identityof the element2


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126C

&ass number@%A

,tomic number@A

0 number of protons 0 Since the carbon is neutral or does notcarr! e8cess positive nor neative chare"

the number of electrons must be e7ual tothe number of protons.

umber of electrons 0


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E


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e(resentin$ Elemental Ions

Ionsare char$ed atoms or molecules

Cationsare (ositi5ely char$ed s(ecies

,nionsare ne$ati5ely char$ed s(ecies

E


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e(resentin$ Elemental Ions

Ionsare char$ed atoms or molecules

E


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Cations

Cationsare (ositi5ely char$edatoms or molecules

+

)a3..

Since the (rotonne5er lea5es the

nucleus, the num#erof (rotons remainsthe same2 >nl! thenumber of

electrons var!.


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Com(utin$ for the char$e

Chare 0 of protons/ 6 of electrons/

+

)a3

..

Based on theformula, a cation

"ould ha5e lesselectrons than itscorres(ondin$neutral element2

of electrons/ 0 of protons/ 6 Chare

$o solve for the number of electrons for a iven ion?


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Cations


Protons 9 ..

)eutrons 9 .

Chare 0 1 0 11 6 8

Solve for 8? 8 0 1: 0 number of electrons

(lectrons 0 1:+)a3

..


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%nions

,nionsare ne$ati5ely char$edatoms or molecules

or anions, there aremore electrons than

(rotons2 $he amountof electrons ine8cess *ould bee7ual to the

manitude of theneative chare2

634

.1

Cl


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%nions


Protons 9 .1

)eutrons 9 ./

Chare 0 - 1 0 1; 6 8

Solve for 8? 8 0 1< 0 number of electrons

634

.1Cl (lectrons 0 1C

.3>C

.*>C

ISOTOPES


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ISOTOPES

C..

>

Protons eutrons Electrons

=

C.

>

C.3>

C.*>

;

<

%t i #


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%tomic mass 5s mass num#er

&ass number 0 of protons/ of neutrons/

&ass number varies for an elementdue to e8istence of isotopes

,verae ,tomic &ass 0 *eihted averae ofthe masses of different isotopes

$he averae atomic mass is the mass

value found in the periodic table

i.e. for Carbon is 12.:11 amu

%t i


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%tomic mass

,tomic mass is e8pressed in terms ofamu atomic mass units/

1 amu 0 1. 8 1:-2


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( )isoto(eofmassatomic.00

a#undanceG%%+

=

%5era$e %tomic +ass @%%+A

$he A*eihtB of each isotope is described

b! its percent abundance in nature

,verae ,tomic &ass 0 *eihted averae ofthe masses of different isotopes

E l f i ht d


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E


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E


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Calculation of %5e %tomic +ass

Cl634Cl631

(ercenta#undance

14243

*2*1

1::.::

+ass inamu

3*2?1

3>2?1

Product

241.3

9:4.

3=4=.9

,,&

3=4=.9

H

1::

3=.4

Calculate the averae atomic of

chlorine?

C l l ti f % %t i +


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Calculation of %5e %tomic +ass

( ) ( ) ( ) ( )amu342*> %%+

amu3>2?102**1amu3*2?1021443%%+=

+=

Eind the averae atomic mass ofChlorine based on the iven data of itst*o isotopes?

Cl-3= 34.9; amu ;=.=3F

Cl-3; 3.9; amu 24.4;F

E l


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E


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E


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Introduction to hemical

ombination

Louie Paolo D. CarpioInstructor 3

Institute of Chemistry, UP Diliman


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OBJECTIVES for today

1. %evie* chemical chanes

2. Differentiate ionic from covalent

compounds

3. Define the mole

4. Define the ,voadroHs number

=. Define the molar mass

. Discuss the t!pe of chemical reactions


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S=ills you "ill learn today

1. Calculatin molar masses

2. Calculatin moles of a substance

based on its iven mass

3. Calculatin the number of particles

4. $o be able to identif! the t!pe of

reaction


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e5ie"& Chemical Chan$es

I)DIC%TOS O CHEMICAL CHANGES

; E5olution of $as

; -eat a#sor(tion or release; ormation of a solid @(reci(itateA

; Color chan$e

Chemical chan$es automatically chan$es the

intensi5e (ro(erties of matter


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e5ie"& Co5alent com(ounds

Covalent compoundsare com(ounds

"hich are com(osed of nonmetallic

elements2

The indi5idual (articles of co5alent

com(ounds are called molecules2+olecules can #e further #ro=en do"n

into atoms2


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e5ie"& Ionic com(ounds

Ionic compoundsare com(ounds"hich are com(osed of cations and

anions @usually metal 8 nonmetalA2

; The indi5idual (articles of an ioniccom(ound are called formula unitsand

not molecules since these units are

arran$ed in a cr!stal lattice2 ormulaunits can #e further #ro=en do"n into

ions2


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Summary& Particle ty(es

.2 Element

@monoatomicA

2 Element

@(olyatomicA

32 Co5alent

com(ound

*2 Ionic

com(ound

P,%$ICL( $P( S&,LL(S$ I$

atom atom

molecule atom

molecule atom

formula unit ion

(8ample

Cu

O

-O

)aCl


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%mount of matter

The amount of matter can #e descri#edin 3 "ays&

; mass ' uantity of matter

; 5olume ' amount of s(ace that a

matter is occu(yin$

; mole' num#er of (articles


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Definition of the mole

&ole

; num#er of (articles contained in .

$rams of car#on6.

; S2I2 unit for the num#er of (articles

; Pac=a$e that contains the %5o$adros

num#er @)%A of (articles "hich is >20 20 < .03

. atom

>20 < .03atoms


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&olar masses of different particles

S(ecific name of molar masses&

; Element @monoatomicA ' atomic mass

; Element @(olyatomicA ' molecular mass

; Co5alent com(ound ' molecular mass; Ionic com(ound ' formula mass

; +ass of a su#stance that contains e20 < .03(articles


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S l i f th b f l


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Solvin for the number of moles

massmolar

mass$i5enmoles=

moles

)ivenmass

&olarmass

( l


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(8ample

.2 Sol5e for the molar mass of )aCl&

)aCl 9 2??0 $mol 8 342*43 $mol 9 =


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Countin particles b! the doJen

7. doMen 9 . (cs

doMens

*24 doMens

0214 doMen

4214 doMens

pieces

* (cs

4* (cs

? (cs

>? (cs

C ti ti l b th l


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Countin particles b! the mole

7. mole 9 >20 < .03

(articles

Kuantit! ofcompound

20 moles C-*

*24 moles C-*

0214 mole C3-

>

4214 moles C*-.0

molecules

.20* < .0*

210? < .0*

*24.4 < .03

32*>.4 < .0*

,toms of C

.20* < .0*

42*./ < .0*

.234*4 < .0*

.23/*> < .0*

C ti ti l b th l


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Countin particles b! the mole

7. mole 9 >20 < .03

(articles

Kuantit! ofcompound

320 moles )aCl

24 moles )aS

.2/ mole )a3PO*

Eormula units

.2/0> < .0*

.2404 < .0*

.20/3> < .0*s

ions of a

.2/0> < .0*

320. < .0*

3240/ < .0*

$ f Ch i l % ti


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$!pes of Chemical %eaction

1. S!nthesis @ Combination2. Decomposition

3. Sinle %eplacement

4. &etathesis @ Double Displacement

=. Combustion

%ead the handout I provided

t ti


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e8t meetin

; Start of reaction stoichiometr!; &a'e sure !ou master the

follo*in s'ills tauht in the lab?

*ritin ionic e7uations"

nomenclature of covalent and ionic

compounds" solubilit! rules and

sinificant fiures pp. 1-22 of thelab manual/

(D >E CL,SS


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(D >E CL,SS

; K(S$I>SGGGM

; Chapters covered toda!?

Chapters =-1 to =-;

Chapters 2-4 to 2-

Chapters 4-< to 4-13

; 5e sure to do*nload handouts

; KuiJ ne8t meetinM

Documents

2nd Day Handout