Date post: | 17-Feb-2018 |
Category: |
Documents |
Upload: | winnie-lim-li-sze |
View: | 218 times |
Download: | 0 times |
7/23/2019 Chapter 5 Energy and Chemical Change Student Copy1
http://slidepdf.com/reader/full/chapter-5-energy-and-chemical-change-student-copy1 1/19
5.1 Physical and Chemical Changes
1
CHAPTER 5 ENERGY AND CHEMICAL CHANGES
5.1 Physical and Chemical Changes5.2 Heat Change in Chemical Reactions5.3 The Reactivity Series of Metals5.4 !!lication of Reactivity Series of Metals5.5 "lectrolysis5.# "lectrical "nergy from Chemical Reactions5.$ %ight and Chemical Reactions
5.& 'nnovative "fforts in the (esign of ")*i!ment+sing Chemical Reactions as So*rces of "nergy
7/23/2019 Chapter 5 Energy and Chemical Change Student Copy1
http://slidepdf.com/reader/full/chapter-5-energy-and-chemical-change-student-copy1 2/19
Physical Changes
1. The most im!ortant thing a,o*t a !hysical change is that only the
_________________________ of a s*,stance change.
2. The follo-ing are the characteristics of a !hysical change.a 't involves a ___________________________________________________
, There is ___________________________ formed.
c 't does ______________________________
d The ____________________________________________
e The changes is _____________________________________
3. The follo-ing are e/am!les of !hysical changes0
a ____________________________________________ , ____________________________________________
c ____________________________________________
d ____________________________________________
4. ,serve the follo-ing e/!eriment to *nderstand a !hysical change.
2
7/23/2019 Chapter 5 Energy and Chemical Change Student Copy1
http://slidepdf.com/reader/full/chapter-5-energy-and-chemical-change-student-copy1 3/19
Chemical Change
1. Chemical changes are changes -hich involve chemical reactions.
2. The characteristics of a chemical change are as follo-s.
a ne- s*,stance -hich has a ________________________________________
, This change involves ______________________ ,eca*se heat energy is *sed
___________________________
c ____________________________________
3. The follo-ing are e/am!les of chemical changes0
a ____________________________________
, ____________________________________
c ____________________________________ d ____________________________________
4. The !rod*cts of heating cannot ,e changed ,ac to the original s*,stances iron
!o-der and s*l!h*r. So this reaction is __________________________________
5. The ne- s*,stance also _______________________________________________
3
7/23/2019 Chapter 5 Energy and Chemical Change Student Copy1
http://slidepdf.com/reader/full/chapter-5-energy-and-chemical-change-student-copy1 4/19
E!e"imen# im 0 To st*dy chemical changesPro,lem _____________________________________________________________________
Hy!othesis _____________________________________________________________________ _____________________________________________________________________ _____________________________________________________________________
!!arat*s ____________________________________________________________________ _____________________________________________________________________
aria,les
6 Mani!*lated0 ________________________________________________________ 6 Res!onding0 ________________________________________________________ 6 Constant0 __________________________________________________________
Proced*re1. Set *! the a!!arat*s as sho-n in Figure 5.2.2. The co!!erll car,onate !o-der is heated.3. The change is o,served.
Res*lt1. The green solid t*rns ,lac.2. The lime-ater t*rns clo*dy.
nalysis and 'nter!retation of (ata1. 7e- s*,stances -hich fe- different com!ositions and chemical !ro!erties8 i.e. co!!er
o/ide and car,on dio/ide8 are !rod*ced. This sho-s that this reaction is a chemicalchange.
2. The e)*ation of the reaction0Co!!erll car,onate9: co!!er o/ide ; car,on dio/ide
Concl*sion ________________________________________________________________________ ________________________________________________________________________ ________________________________________________________________________
4
7/23/2019 Chapter 5 Energy and Chemical Change Student Copy1
http://slidepdf.com/reader/full/chapter-5-energy-and-chemical-change-student-copy1 5/19
Ee"cises 5.1
Pa!e" $% Sec#i&n C
<ig*re 1 ,elo- sho-s a !hysical change.
a State fo*r reasons -hy the reaction in <ig*re 1 is a !hysical change. =4 mars>, St*dy the information in <ig*re 2 and e/!lain the conce!t of chemical change. ?o*r
ans-er sho*ld ,e ,ased on the follo-ing ste!s.6 Maing o,servations =1 mar>
6 'dentifying similar characteristics of <ig*res 2a and 2, =2 mars>6 Relating the characteristics of the chemical change in order to constr*ct the
conce!t of a chemical change =1 mar>6 Stating an e/am!le of chemical change and one e/am!le of non9chemical change
=1 mar>6 State the act*al conce!t of chemical change =1 mar>
________________________________________________________________________ ________________________________________________________________________ ________________________________________________________________________ ________________________________________________________________________
________________________________________________________________________ ________________________________________________________________________ ________________________________________________________________________ ________________________________________________________________________ ________________________________________________________________________ ________________________________________________________________________ ________________________________________________________________________ ________________________________________________________________________ ________________________________________________________________________ ________________________________________________________________________ ________________________________________________________________________
________________________________________________________________________ ________________________________________________________________________ ________________________________________________________________________
5
7/23/2019 Chapter 5 Energy and Chemical Change Student Copy1
http://slidepdf.com/reader/full/chapter-5-energy-and-chemical-change-student-copy1 6/19
5.$ Hea# Change in Chemical Reac#i&ns
1. 'n a chemical reaction8 heat energy may ,e __________________________ 2. Heat energy is a,sor,ed to ________________________________ -hereas heat
energy is released -hen ___________________________________
End&#he"mic and E&#he"mic Reac#i&ns
6
7/23/2019 Chapter 5 Energy and Chemical Change Student Copy1
http://slidepdf.com/reader/full/chapter-5-energy-and-chemical-change-student-copy1 7/19
Ind's#"ial Chemical Reac#i&nsThe Ha(e" P"&cess )The !"&d'c#i&n of amm&nia in ind's#"y*1. The !rod*ction of ammonia thro*gh the Ha,er Process involves the reaction ,et-een
nitrogen and hydrogen gases mi/ed in the !ro!ortion of 103.
2. a The Ha,er !rocess is an ______________________________________ , 't is a reversi,le !rocess for-ard and ,ac-ard reaction.
3. 'n the Ha,er !rocess8 the follo-ing conditions m*st ,e satisfied for the o!tim*m
!rod*ction of ammonia i.e. for the for-ard reaction to occ*r.a Tem!erat*re0 't sho*ld ,e lo-8 ,*t lo- tem!erat*res can slo- do-n the reaction.
_______________________________________________________ , Press*re: high8 i.e. _______________________________________ c Catalyst: _______________________________________________
The C&n#ac# P"&cess
1. The contact !rocess is an ind*strial !rocess to !rod*ce ________________________ 2. The o!tim*m conditions to !rod*ce s*l!h*ric acid are...
a tem!erat*re: ___________________________ , !ress*re: ______________________________ c catalyst: _______________________________
3. S*l!h*ric acid is *sed...a in the !rod*ction of _____________________________
, in the !rod*ction of _____________________________ c as the ______________________________________ d as a _______________________________________
7
7/23/2019 Chapter 5 Energy and Chemical Change Student Copy1
http://slidepdf.com/reader/full/chapter-5-energy-and-chemical-change-student-copy1 8/19
5.+ The Reac#i,i#y Se"ies &- Me#als
Reac#i&ns &- Me#als i#h /a#e"
1. Reactive metals react -ith -ater to !rod*ce alaline sol*tions and hydrogen.
2. Potassi*m8 sodi*m and calci*m are the only three metals that can _________________
______________________
3. The follo-ing are the e)*ations for the reactions of metals -ith -ater.
A. P&#assi'm and s&di'm "eac# ac#i,ely i#h c&ld a#e"
Potassium + water potassium hydroxide + hydrogen
Sodium + water sodium hydroxide + hydrogen
0. inc can &nly "eac# i#h s#eam &" h&# a#e"
Zinc + water zinc hydroxide + hydrogen
C. N&n%"eac#i,e me#als s'ch as ________________________ d& n&# "eac# ei#he" i#h
c&ld a#e" &" h&# a#e"
Reac#i&ns &- Me#als i#h Acids
1. ery reactive metals _______________________________ react actively -ith dil*te
acids.
2. The !rod*cts of these reactions are salt and hydrogen.
3. The reaction ,et-een a reactive metal and an acid may ca*se an e/!losion.
Eam!le
8
7/23/2019 Chapter 5 Energy and Chemical Change Student Copy1
http://slidepdf.com/reader/full/chapter-5-energy-and-chemical-change-student-copy1 9/19
Me#al Acid Reac#i&n Ligh#ed
s!lin#e" #es#
P"&d'c#s
magnesi*m
magnesi*m
@inc
@inc
co!!er
co!!er
Reac#i&ns &- Me#als i#h 2ygen
1. Ahen metals are heated in the !resence of o/ygen8 they -ill ,e o/idised to !rod*cemetal o/ides.
2. very reactive metal -ill ,*rn -ith a in o/ygen.3. The more reactive the metal is8 the -ill ,e.4. The reactivity of metals -hen going do-n the reactivity series of
metals.
9
Metal + Ox en Metal Oxide
7/23/2019 Chapter 5 Energy and Chemical Change Student Copy1
http://slidepdf.com/reader/full/chapter-5-energy-and-chemical-change-student-copy1 10/19
P&si#i&n &- Ca"(&n in #he Reac#i,i#y Se"ies &- Me#als
1. Car,on is !laced in ,et-een in the reactivity series.
2. There are t-o methods that can ,e *sed to determine the !osition of car,on in the
reactivity series.
a __________________________________________________
(*ring the reaction8 the metal -ill glo- and change in colo*r.
ll metals !laced _________________ in the reactivity series can react -ith car,on
, _____________________________________________________
(*ring the reaction8 the metal -ill glo- and ,lac s!ots -ill ,e formed on the -all of
the gas Bar.
ll metals !laced ____________ in the metal reactivity series -ill react -ith car,on
dio/ide.
Reac#i,i#y Me#al Reac#i&n i#h
a#e"
Reac#i&n i#h
dil'#e acids
Reac#i&n i#h
&ygen
6 ll react vigoro*sly
-ith a hissing
so*nd
6 Hydrogen gas is
released
6 Metal hydro/ides
are formed
6 ll react very
violently These
reactions are
e/tremely
dangero*s
,eca*se they may
ca*se e/!losions
6 Reacts readily
6 Hydrogen gas is
released
6 Calci*m hydro/ide
is formed
6 (o not react -ith
cold -ater
6 React -ith hot
-ater or steam6 Hydrogen gas is
released
6 React readily and
give off gas
,*,,les
6 Hydrogen gas isreleased
6 Metal salts are
formed
10
7/23/2019 Chapter 5 Energy and Chemical Change Student Copy1
http://slidepdf.com/reader/full/chapter-5-energy-and-chemical-change-student-copy1 11/19
Ee"cises 5.+1. (iagram 2 sho-s the set9*! of a!!arat*s for an e/!eriment carried o*t to st*dy the
reactivity of metals -ith o/ygen.
The e/!eriment is carried o*t three times -ith three different metals8 8 Y and D. Ta,le 2
sho-s the res*lts of the e/!eriment.
Me#al 2(se",a#i&n
E*rns ,rightly
Y Flo-s
Z E*rns less ,rightly
Table 2
a Ho- can yo* no- that a reaction has taen !laceG
=1mar>
, i Ahat is formed -hen a metal reacts -ith o/ygenG
=1mar>
ii Arite a general -ord e)*ation to sho- the reaction ,et-een a metal and
o/ygen.
=1mar>
c rrange metals X, Y and D according to their reactivity -ith o/ygen in descending
order
=1mar>
11
7/23/2019 Chapter 5 Energy and Chemical Change Student Copy1
http://slidepdf.com/reader/full/chapter-5-energy-and-chemical-change-student-copy1 12/19
5.3 A!!lica#i&n &- Reac#i,i#y Se"ies &- Me#als
E#"ac#i&n &- Me#al1. Metals are ____________________________________ 2. The methods of e/traction of metals de!end on _______________________________ 3. The ta,le ,elo- sho-s the methods of e/traction of certain metals.
Me#al Me#h&d &- e#"ac#i&nPotassi*m
Sodi*m
Calci*m
Magnesi*m
l*mini*m
Car,on
Dinc
'ron
Tin
%ead
Co!!erMerc*ry
Silver
Fold
E#"ac#i&n &- TinThe e/traction of tin involves t-o !rocesses8 i.e. the _____________________________ ___________________________________
Hea#ing !"&cess1. This !rocess is carried o*t to ______________________________________________ ____________________________________________ 2. (*ring this !rocess8 ____________________________________________ _________
-hereas ________________________________________________ 3. The tin ore is heated -ith coal car,on at ____________________________________
Red'c#i&n !"&cess1. Ahen heated8 the tin ore -ill ,e red*ced to tin !*re metal2. The _____________________ flo-s o*t into _________________________________
12
7/23/2019 Chapter 5 Energy and Chemical Change Student Copy1
http://slidepdf.com/reader/full/chapter-5-energy-and-chemical-change-student-copy1 13/19
3. _____________________________________________ is mi/ed into the ,last f*rnace __________________________________________________________
Ee"cises 5.3
(iagram $ sho-s the e/traction of tin ore at high tem!erat*re in a ,last f*rnace.
a 7ame t-o elements in P.
=2 marks>
, State one reason -hy car,on is a s*ita,le element to *se in the e/traction of tin orefrom P.
=1 mar>
c 7ame gas .
=1 mar>
d Ahat is the f*nction of limestone in this !rocessG
=1 mar>
e 7ame !rod*ct R.
=1 mar>
13
7/23/2019 Chapter 5 Energy and Chemical Change Student Copy1
http://slidepdf.com/reader/full/chapter-5-energy-and-chemical-change-student-copy1 14/19
5.5 Elec#"&lysis
Elec#"&ly#e4 C'""en# and Elec#"&de1. "lectrolysis is __________________________________________________________ ________________________________________________________________
2. The three main com!onents of electrolysis are...a the electrolyte 9
______________________________________________________ , a direct c*rrent so*rce 9 _______________________________________________ c t-o electrodes 9 _____________________________________________________
3. The electrodes -hich are involved in electrolysis are no-n as the
_________________ a The anode is a ______________________________________________________
, The cathode is a
_____________________________________________________ 4. ?o* have to no- that !ositively charged ions are no-n as ___________ . Cations are
____________________________________ 5. nions are __________________________ -hich are attracted to the ____________
#. "/am!le: "lectrolysis of _________________________________
a t the anode 9 ________________________________________________________ , t the cathode 9 ______________________________________________________ c "lectrodes I _____________________________________________________ d "lectrolyte 9 molten lead '' ,romide is *sed lead '' ,romide !o-der is heated *ntil
it melts ,efore the e/!eriment is started8e Aord e)*ation0 ________________________________________________
A!!lica#i&n &- Elec#"&lysis % E#"ac#i&n &- Reac#i,e Me#al1. Metals s*ch as al*mini*m8 magnesi*m and calci*m are _________________________
These metals __________________________________ ,y *sing car,on !lease refer
to the !rocess of e/traction of metals ,y *sing a ,last f*rnace.2. l*mini*m is e/tracted from its ore8 ,a*/ite al*mini*m o/ide ,y __________________
14
7/23/2019 Chapter 5 Energy and Chemical Change Student Copy1
http://slidepdf.com/reader/full/chapter-5-energy-and-chemical-change-student-copy1 15/19
3. The e/traction of al*mini*m is descri,ed ,elo-.
A!!lica#i&n &- Elec#"&lysis % P'"i-ica#i&n &- Me#als
1. 'm!*re metals can ,e changed into !*re metals ,y electrolysis.2. 'n this !rocess8 the im!*re metal is *sed as _____________ -hereas a !iece of the
!*re metal is *sed as _________________ 3. salt sol*tion containing the ions of the metal that is to ,e !*rified is *sed as the
A!!lica#i&n &- Elec#"&lysis一
Elec#"&!la#ing1. metal o,Bect can ,e ______________________________________ ,y electrolysis.2.Metal o,Bects made of iron r*st easily in the !resence of -ater and o/ygen.3.So8 the !rocess of electro!lating can ,e *sed to __________________________ 4.ther than that8 electro!lating can mae metal o,Bects loo more attractive and shiny.
15
7/23/2019 Chapter 5 Energy and Chemical Change Student Copy1
http://slidepdf.com/reader/full/chapter-5-energy-and-chemical-change-student-copy1 16/19
5. Elec#"ical Ene"gy -"&m Chemical Reac#i&ns
1. Cells can ,e classified into t-o gro*!s8 i.e:
a !rimary cells 9 .
, secondary cells 9
2. Primary cells are the
3. Secondary cells are the
Ty!e &- cell Ad,an#ages Disad,an#ages
16
7/23/2019 Chapter 5 Energy and Chemical Change Student Copy1
http://slidepdf.com/reader/full/chapter-5-energy-and-chemical-change-student-copy1 17/19
(ry cell
%ead9acid
acc*m*lator
laline ,attery
7icel9cadmi*m
,attery
Silver o/ide I
Merc*ry ,attery
E!e"imen# 5.
Aim6 Ma#e"ial6 A!!a"a#'s6 P"&ced'"e61. Eoth the co!!er !late and @inc !late are sand!a!ered.2. sim!le cell is set *! as sho-n in <ig*re 5.4J.
17
7/23/2019 Chapter 5 Energy and Chemical Change Student Copy1
http://slidepdf.com/reader/full/chapter-5-energy-and-chemical-change-student-copy1 18/19
3. The circ*it is closed.4. The changes to the ammeter8 @inc !late and co!!er !late are o,served.,servation0
2(se",a#i&n In-e"ence
mmeter
Dinc !late
Co!!er !late
Co!!er s*l!hate
sol*tion
Disc'ssi&n61. a Dinc8 -hich is more reactive than co!!er8 acts as the _________________________
, The @inc atoms release electrons to form __________________________________ -hich move into the sol*tion.
c Th*s8 the @inc !late _________________________________ 2. The electrons flo- from the @inc !late to the co!!er thro*gh the connecting -ire. 't is
detected ,y ____________________________________________________
3. a The co!!er !late acts as ______________________________________________ , Positively charged co!!er ions in the electrolyte are _________________________
and _____________________________ from the co!!er !late to form co!!eratoms.c Co!!er atoms are ________________________________________________ d Hence8 the co!!er !late ______________________________________
4. The ,l*e colo*r of the co!!er s*l!hate sol*tion _________________________ as theco!!er ions in it __________________________________________
C&ncl'si&n6 sim!le cell converts chemical energy to electrical energy.
Ee"cise 5.
a State t-o advantages and t-o disadvantages of the lead9acid acc*m*lator.
18
7/23/2019 Chapter 5 Energy and Chemical Change Student Copy1
http://slidepdf.com/reader/full/chapter-5-energy-and-chemical-change-student-copy1 19/19
=4 mars>
, st*dent fo*nd that the iron s!oons in his school la,oratory -ere r*sty."/!lain ho- he co*ld !revent the s!oons from r*sting.
?o*r e/!lanation sho*ld incl*de the follo-ing as!ects0
6 'dentify the !ro,lem =1 mar>
6 The method *sed =1 mar>
6 "/!lanation of the method =4 mars>