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2552 RUMTL Chiang Mai

 

Stoichiometry

By Chollada Kulwat


Chemistry for Engineers

Stoichiometry

 4  !""# $#%& ภภ ภ        ภ    ภภ ! ภ"#  

4.1

)*  +,-. !""# $#%&  !""# $#%& (Stoichiometry) 1ภD:ภŕ¸

Metron = ภ*#C

Stoicheion = %3A

 

 ภ ภภ!ภ " #"   ภภ$ " % %&' ()$ %"&'

" %* " " #"( )ภ* +((" % %&'& ,-. ภ/ !ภ#  ภ   ภภ .!* )0"+()ภ1  "  )/)*01#ภ" 34 (Hypothesis) )" 2!(""  ( .!& /" 3  !4()3ภภ ( -. .! 05 !4()3ภภ ( 

63 !4() $))" %*%()ภ%/) 2!4() 3ภภ ( 9:; (Theory) %7 3ภ

6 .!

6%*()ภ%/)  !4()3ภภ (-8 " &ภ +(4 # )%() 

6%*83ภ  1 ภ; (Law)

 132


Chemistry for Engineers

Stoichiometry

%7 # 3ก 1 ก1 -%ก" 3   &  2! $ (-) -9-. (-)(  %" 4()5 - . ( ,ก%* 3  ก 4() $+ ,-.#"/ก.0" #"1ก"ก2 020 !%" ก"ก$

4.2

ก;. *E (Law of Mass Conservation)

"%"2 ' 5) %*ก1** (..1774) )" "#  ก    (8 "$1ก 3)ก ก! "$11" 3)ก

%"# # ก@2 N2 28 ก% 0 ก  ก%/ก@2 H2 6 ก% # 4()ก@2 NH3 34 ก%

"ก# ก ( ก   (N2 + H2) = 28 + 6 = 34 ก%

= 34 ก%

"-% ก ( ก   (NH3) # *กก N 2 + 3H 2 → 2 NH 3

" %* ) N2 1 +  (2 ×14 = 28 ก% ) " ก%/ H2 3 +  (3 ×2 ×1 = 6 ก% ) = 28+6 = 34 ก%

"5 J%K' NH3 2 +  = 2(14+(3×1)) = 34 ก%

(%%* "ก# ก ( ก   = "-% ก ( ก   3#*-+G. 4.1 0*030" 20 ก% 4ก()"4MMN44()%ก#-! /"# .! ก (ก@2 H2 2 ก% 3 ก (ก@2 O2 16 ก%  *0 -.# 2 ก% 3(-) -9"#ก ก ( ก  * 4  ก1  "  "ก# ก ( ก   = "*0 = 20 ก%

"-% ก ( ก   = "ก@2 H2+ "ก@2 O2 + "*0 ! -. = 2 + 16 + 2 = 20 ก%

3 -9"# "ก# ก ( ก   #ก%/ "-% ก ( ก   2! 4 

ก1  "

 133


Chemistry for Engineers

4.3

Stoichiometry

ภ;"#C"G*). (Law of Definite Proportions) +3 2M ' 5) %*ภ1**  " ! 18 )" "#  4" 5ภ  /ภ!6 1   /** 2//ภ! $ ภ*$ 1 4 ภภ 2ภ7

# *0 # ภ/()"& , H  O 2!33  4()-" & # 2H 2 + O 2 → 2H 2O CuSO 4 .5H 2O → CuSO 4 + 5H 2 O NaOH + HCl → NaCl + H 2O

4 #"#3  ()"" &(ภ9  3/"#% #"+( " H:O *03 #  1:8  

"   H = 1 , O = 16 (%%* H:O *0 = 2:16 = 1:8 3#*-+G. 4.2 .! 5 C 30" 1.2 g ภ ภ"# ))ภ2 330" 3.2 g ภ 0 ภ ( ภ%/ C 30"* .!-) ภ(  CO2 - (  .!0 CO2 ! ภ(3ภภ 0 ภ - ภ%/ ภ( ภ. /"# CO2 ! ภ(*30" 2.2 g  C # 0.6 g 3(-) -9"# 'ภ/ CO2 4  ภ1%(#" ! 

.! 5 C ภ % #"+( " C:O  CO2 = 1.2 : 3.2 = 3 : 8 .!-  0 ภ ภ%/ภ( ภ.

"ภ2 3 CO2 = 2.2 T 0.6 = 1.6 % #"+( " C:O  CO2 = 0.6 : 1.6 = 3 : 8

3 -9"# % #"+( " C:O  CO2 # !   4 #"#3  CO2 +( " &(ภ9  2! 4  ภ1%(#" !

4.4

ภ;"#C"G*$A)0! (Law of Multiple Proportions) 3-' ( % 5) %*ภ1** (..1803) )" "#

 134


Chemistry for Engineers

Stoichiometry

0 5 2 5ภ ภ /ภ!2ภภ 1 6 #" " 5 1 : ภ!"*ภ51  / 3!ภ 2  " 3  "   # N2 " ภ%/ O2 4() NO, NO2, N2O, N2O3  N2O5 $)-) " N ภ/ %* 5  ( # ! " O  %* 5 .! / /ภ%34()   %") 8 3. 4.1 "

M"C. *E,-. O O"Pภ- 5 QCRภC1ภภ* 3#*,-. N ภ# O *E* 3#*$-Cภ# *E* $-Cภ# R T- *E,-. N ). N O N O 14 16 14 16 14 32 14 32 28 16 14 8 28 48 14 24 28 80 14 40

NO NO2 N2O N2O3 N2O5

" O  NO : NO2 : N2O : N2O3 : N2O5 = 16 : 32 : 8 : 24 : 40 = 2 : 4 : 1 : 3 : 5

3 -94()"# .! " N  ! " O !"

%"(ภ%/ N ภ/ #8 3 / /ภ%4()   %"# !0 ("# ภ"

%" N2 ภ%/ O2 4  ภ1 %(#"-, 3#*-+G. 4.3 ภ42('ภ0 $% (  ( ! 1 ภ/()" ภ0 $% 50% +( "  ( ! 2 ภ/()" ภ0 $% 40% +( " 3(-) -93 "# %"  -#* 4  ภ1%(#" -,  ภ42('ภ0 $% (-! ภ/()" S 50 -#" " O 50 -#" " ภ42('ภ0 $% ( ! 2 ภ/()" S 40 -#" " O 60 -#" " $)-)& , S & , ! ) 50 -#" "  " ! S ภ42('ภ0 $% ( ! 2  S 40 -#" " 3  O = 60 -#" "

 135


Chemistry for Engineers

Stoichiometry

60 × 50 = 75 -#" " 40

" O ก42(' %* 2  ( 2! #"

%"(ก%/ " ! S 30" 50 -#" " .!0  /ก% % #"34() #ก%/ 50:75 = 2:3 2! % #"  30" %")8 4  ก1%(#"-, MUVก#C 4.1 1. OกCE-.R$T-"#"Aก;. *E,-." 1P3-.)*)A ".OCRW$RX: ก. ,-J !3 ) 0 ก  ก% . ก5  .!-) ) 0 ก  ก% . ก"/, ก@2 ! ก (3ก ก   . ก"/, 4 #-) ก$# % 2. 1ก0MEP,- 0E3G-YZ 1.M"C.OR[*GRWY3 ก;"#C"G*). $)ก42('ก0 $% ( ! 2  S 50 -#" " 3  O =

 ก   ! ก (* .

CuO + H 2 → Cu + H 2 O

J + CuO = 41.538 ก%

= 82.279 ก%

-( %" + CaCl2 E#.R\ J +  = 37.538 ก%

-( %" + CaCl2 = 86.779 ก%

Oก*R)P&"Pก-]#EY^C&,-.RE[กQC_. $*GPก-C*+RE[ก 63.4% bC+ *E RET-RWก/ Pc# c/RE[ก 11.0 ก# R\* ก#ก/ Pc# 5.0 ก# E#.1ก RกCeก+" 0!& 1PYC"Pก-]#EY^C&กก# RET-RE[กT-ก/ Pc#กก# c กCE-.ZRWY3 ก;"#C"G*). %3A A MEP %3A B /eก+ก#YCRW"Pก- C R$+.QCRC+* bC+ ,- 0E1ก กCE-.C#.Z *EOQ3-R 3 (ก# ) )#Z. *E,-. C (ก# ) A B 1 3 4 4.5 2 5 6 7.5 3 15 6 18.0 กG-R\

3.

4.

 136


Chemistry for Engineers

4 5

20 30

6 4

Stoichiometry 18.0 12.0

ภ. 1.)/*!-#3"G*bC+ *E,-. A:B /eภ+$-Cภ# ,. cOQ A MEP B -+G.EP 10 ภ# 1PYC C ภภ#  % %&' " 0%\ #ภ- ภ" -'    # ภ-" ) )++2 (O3) /ภ ภ" -'-)& , #8 # -  03ภ# ภ .ภ)ภ " & #8ภ !$#-   .*  

#8ภ9) % %&' %* *

4.5

9:;-P3- ,-.CE3#

3-' ( % 5) %* 1  *] ..1808 .!)& /ภ1 #8 # ภ1  " ภ1%(#" ! 1  ภ#""# 1. # ภ/()",J 9ภ8 ภ"#   2!3/#ภ-) 9ภ4ภ4 #4() 2.   & , ( ("ภ% #

 /% - .ภ% ,ภภ 3.   & , # (ภ% #

 /% #ภ% 4.   34 #\-43 0-) ภ(*- #4 #4() 5. ภ/ ภ(*4()()"ภ"

%"  & , # (ภ% 30" 

& , # (ภ% ! "

%"ภ%%* 4()"% #" !   %") 8 6. + ภ,ภ/ ( ("ภ% #

 /% - .ภ% ,ภภ  ภ# 3ภ+ ภ,ภ/.! 8 ^33,/% 1  ( %  ! 4 # 3 /# # ,- 1 4 #3 #   " ' 2!/"#   ภ/()" 9ภ +   "   sub-atomic particle ,- 2 4 #3 # Isotope 2!& , ( ("ภ% ! 4+2+ ภ% 3  " #ภ% ) 4 4 #3 #   " ' Mk ภ' " ' 1  ( %  $0 & /ภ1  " ภ1%(#" ! (%*

 137


Chemistry for Engineers

Stoichiometry

1. ภ& /ภ." ) 1  ( %) 4 ภ !5" ภ# -% ภ  #ภ% 30"  4 #4()\--. ภ(*- #   3 ภ!ภ% .! ภ( ภ  2. ภ& /ภ. * ) 1  ( %) 2, 5 ภ !% #"+(

"& , !" ภ% ภ/%* !  .!  & , # (ภ%  " ภ% ภ/ 3" ภ%()"% #"30"   !  .!3ภ  & , ( ("ภ%  /% - .ภ%  " #ภ% % #"+( "& , !" ภ% ภ/3 !()"

4.6

*E-P3- (Atomic mass)

 

( 9ภภ(%%* "ภ9#

#) ภ()" ภ !3/,  lภ% m # 4 # ("ภ( %3 (" & !3- "  & , #8 +(ภ / /ภ%/ "   & ,  6 +( / /ภ%/ "  & ,  6 +( / /3ภ" !& , %*8 0 ภ (ภ%/ "& ,  6 ( % /"# H & , ! / !,( 3 -)) H & ,  6 ภ0-("# H 1    " 1 -#"  6 (1 amu) (amu # 3ภatomic mass unit, 1 amu # #ภ%/ 1.66Ă—10-24 ภ% ) 3ภ ภ  ! H "

%"ภ%/ O *0 ( % -" % %&' " O  H 4() (%*

"O 8 =

"H 1 $) %*

6"# *0 ภ(3ภO 1   0 ภ ภ%/ H 1   34()"#

"O1 

= 8 = "  ภ2 3

"H 2  

#  3'4()"# H " ภ%/ O ()"% #"30"  = 2 : 1 34()"#

1  - ( 2

"O1  8 =

"H 2   1

 138


Chemistry for Engineers

"O1 

=1

Stoichiometry

8

1 [ "H 2   ] [1] 2 2

"O1 

= 8 Ă— 2 = 16 = "   O

"H 2 

()"" &ภ -#* 0-)( % - "  & ,.!84()ภ-& , $ )"#3 4 #4()# !$ภ)  #" &ภ ภ9 .*6 ภ-# "  & , !$ภ) !* 3 -9"# $)      "  (( % 34() "# %* 1  

"& ,

"  & , = 1 [ "ภ2 3 1   ] 16  # .!3ภ%ภ ) " o! ,ภ4+2+ ภ2 3 ! #&  

 6  #%ภMk ภ') o O-16   6 (%%*  6    " 

# = 1.00272 #  6 Mk ภ' 3 0-) %/ .!-)   6 ("ภ% %ภ"  '34()) C-12 2! 4+2+  !   1

ภ!,(&  '/   6 +(ภ0-(-)  " C-12, 1 12   #ภ%/ 1 -#"  6

"  & ,

"& ,%* 1  

=

1 [ " C-12, 1   ] 12

;"/< #ภ%/ ;" 1 /< #4 "/ T  " / / /ภ-) /"# & ,%*8 1   -%ภภ! # "& ,

 6 T 4 # -#" " 1 / T  " ! )3 & ,%*8 1  

T -#"  amu, g (1 amu = 1.66Ă&#x2014;10-24 g)  139


Chemistry for Engineers

Stoichiometry

4.6.1 ภ)/*! *E-P30"4()-" & *#ภ%/%ภ)  !ภ0-(-) # - 0"3ภภ / /ภ%/& ,4r+( 3-.& , C-12 - 0"3ภ ภ    - 0" "  o!4+2+  4.6.2 ภ)/*! *E-P3- 1ภภR+R+ภ# H T- C 3 + 330" / /ภ%/ H -. C-12 +(  -.33 / /ภ%/& ,.!8 ! / "  )"ภ94()  !ภ#" ) ) 4.6.3 ภ)/*! *E-P3- 1ภeภ+R) ,-.%3A 0-%/ภ !& , #8 %* # 2  (*4 ภ( ภ "

%"4() ภ/  1  (   ภ %!"84 4()(%*

#

& , A + & , B + ............... & , Al + & , O & , Mn + & N

ภ/ AXBY........................ ภ/ Al2O3 ภ/ Mn3N2

ภ !3- "  & , 3 ) / ภ. "& , ! 0 ภ (ภ% . "  & ,(& ,-! .  ภ/ ! ภ(*  ) ภ ! ภ(5 J%K' ภ/  ( (" #%* ภ0" "  & ,330"3ภ ภ +(  ภ-)$ภ))" )+  )#" -.330"+() #8 +(4 # )  ภ(%*

WA M A x = Ă&#x2014; WB M B y WA , WB MA , MB x,y

= "& , A  B  0(%/ ! 0 ภ (ภ% = "  & , A  B  0(%/ = 30"  & , A  B ภ/  140


Chemistry for Engineers

Stoichiometry

x 3-4()3ภ ภ/ #%* (%%*ภ0" "  3 ) / y  ภ/ ! ภ(* x 2 Al + O 2 â&#x2020;&#x2019; Al 2 O 3 ; = y 3 x 3 A + B â&#x2020;&#x2019; A 3B ; = y 1 x 1 Cr + Cl 2 â&#x2020;&#x2019; CrCl 3 ; = y 3  (%ภ#"ภ3ภ3)ภ%/ภ/ ! ภ(3ภ& , 2  ()" % $)ภ%/ ภ/ ! ภ(3ภ& , ภภ"# 2  (4()()" #

3#*-+G.RQG

ภ/ A2B4C7

& , A + & , B + & , C

.! )ภ3- "  & ,( ภ90& ,%*4 /ภ%/& ,2! / " 

#)" 

"# / "  & , A 3- "  & , C ภ9 04()+( / % #"-"#& , A ภ%/ C (%* WA M A 2 = Ă&#x2014; WC M C 7

   A2B4C7  0-%/ A ภ%/ C #ภ%/ .! / " A (WA)  C (WC) ! 0 ภ (ภ%  / "   A ภ9- "   C 4()  0 ("ภ% .! )ภ- "  & , B ภ9 /ภ%/& , A # ("ภ% +() WA M A 2 = Ă&#x2014; WB M B 4 ภ3ภ3)0" "  )" -%ภภ(%ภ#"*% $)0"+  + ภ,ภ/ -.0"30"*05ภ! #ภ/4() +( !ภ/ ! *05ภ%* %ภ   ภ A + nH 2 O â&#x2020;&#x2019; A.nH 2 O MEP)/*!bC+OQ"03  141


Chemistry for Engineers

Stoichiometry

WA M 1 = A Ă&#x2014; WH 2 O M H 2 O n WA , WH 2 O

. " A  H2O  0(%/5ŕ¸

MA ,MH2O

. + ภ, A  H2O  0(%/

n . 30"*05ภ (%ภ#" 33)-30"*05ภ-.- "+ ภ, -. "  & ,/ & , .! /30"*05ภ ##4ภ9  " % %&'   (%ภ#" 3)0" "  4() o ภ !& , #8 " ภ%)"4()ภ/  ( (" #%* $)4()ภ/ ภภ"# 1  (3)4 #4() ( )0"3ภ ภ) # & , A + & , B A2B + AB3  ภ (%ภ#"3) 0" "  4 #4() 4.6.4 ภ)/*!-P3- RkE+1ภY-b]b )/*!YC1ภ"033G-YZ M=

M â&#x2C6;&#x2018; % A

â&#x2C6;&#x2018; %A = (%A ) + (%A 1

100

2

) + .............

100

= =

"  o!4+2+  summation (5" )

= =

 )&  4+2+  # %"

"  4+2+  # %" ($)+3 '4 #ภ0-(

"   -) 33)  " 4())

 (ภ0" "  o!4+2+ -)( .!  

)" 3#*-+G. 4.4 "   Na = 23 3-"#

 142

! 


Stoichiometry

Chemistry for Engineers

ภ. Na 1   -%ภภ!ภ%

. Na 5   -%ภภ!ภ%

 ภ. Na 1   -%ŕ¸

= = = = =

. Na 5   -%ŕ¸

"   Na Ă&#x2014; 1.66 Ă&#x2014;10-24 g 23 Ă&#x2014;1.66 Ă&#x2014;10-24 g 38.18 Ă&#x2014;10-24 g Ans 5 Ă&#x2014; 38.18 Ă&#x2014;10-24 g 190.9 Ă&#x2014;10-24 g Ans

"  !( & ,       "  o! 4+2+ &  &  & , #84 #4()  4+2+  (" (% %"# #4

3#*-+G. 4.5 &  & , Si  3 isotope . Si-28, Si-29, Si-30 # 92.21%, 4.70%, 3.09%  0(%/ " isotope %*

# #ภ%/ 27.977, 28.976  29.974 amu 3 0"- "  o! Si 

"  o! Si 1  

=

C#.#Z *E-P3- RkE+,-. Si

= 28.086

(92.21Ă&#x2014; 27.977) + ( 4.70 Ă&#x2014; 28.976) + (3.09 Ă&#x2014; 29.974 ) 100 = 28.086 amu 3-

^33,/%  $-# "  & , #8()"" & Mass spectrograph 2!  " & ! )% .! . " %* ))" &0"%*ภ#)  3#*-+G. 4.6 .!0+- X 1.4 ภ%  53" (ภ%/ภ2 3 0.6 ภ% $)ภ42('*   + ภ, X2O3 "   X # #4 # *

X + O2 â&#x2020;&#x2019; X 2O3  143


Stoichiometry

Chemistry for Engineers

Wx M x 2 = Ă&#x2014; WO M O 3 1.4 M x 2 = Ă&#x2014; 0.6 16 3 1.4 Ă&#x2014; 3 Ă&#x2014;16 = 56 Mx = 0.6 Ă&#x2014; 2 *E-P3- ,-.bEP X = 56

3-

MUVภ#C 4.2 1.  2 (Ca) 1   -%ภภ!ภ% $) "   Ca = 40 (6.64Ă&#x2014;10-23 ภ% ) 2. & , A 2    "  3 #& ,4+  3 5   30" "  

" 1   & , A (105, 1.74Ă&#x2014;10-22 ภ% ) 3. $)0 NiCl2 1.296 ภ%  0-) +- Ni ภ%/ภ@2()"" &ภ 4MMN " +- Ni !4() = 0.587 ภ% $) "   = 35.453 # "   +- Ni  #( (58.7) ( ภ. NiCl 2 â&#x2020;&#x2019; Ni + Cl 2 ) 4. ภ/ (-!ภ/()" 3 & , & ,ภ. Z  Y 4 # / " 

#"& , ! 3  ภ2 3 ภ/* /"#    Z2YO4 3ภภ " -'ภ1"#  Z = 32.39% , Y = 22.54%  O = 45.07% 3- "   Z  Y $)-ภ"   O  16.00( "  Z=23 , "   Y=32) ( ภ. Z 2 YO 4 â&#x2020;&#x2019; 2Z + Y + 4O ) 5. $) 14 ภ%  X 0 ภ (ภ%/ 16 ภ% ภ2 3 & , X  "  #( $)ภ42(' X    XO (14) ( ภ. 2X + O 2 â&#x2020;&#x2019; 2XO )

4.7

*Eb REภAE  

ภ  3G.ภ#    1

ภ  -+G.Y

 144


Chemistry for Engineers

Stoichiometry

"4"ภ5" T  " / / /ภ-) /"# "%* 1 + ภ, -%ภภ! # " & ,  6 T 4 # -#" " 1 4"ภ5" T  " ! )3 %*8 1 + ภ, T -#"  amu, g (1 amu = 1.66Ă&#x2014;10-24 g) 4.7.1 *%ภ *Eb REภAE 0"4()-" & *#ภ%/%ภ)  !ภ0-(-) # - 0"3ภภ / /ภ%/& ,4r+( 3-.& , C-12 - 0"3ภ" 

- 0"3ภ+  - 0"3ภ ภ    - -.0"()"" &.!8 4.7.2 ภ)/*! *Eb REภAE1ภภR+R+ภ# H T- C

" 1 + ภ, =

"+ ภ, Ă&#x2014; 1.66 Ă&#x2014;10-24 ภ%

"+ ภ,

=

" 1 + ภ,

" H 1  

=

" 1 + ภ,

" C 1  

-. 330"+(ภ / /ภ%/& ,.! 8 ! / "  )"ภ94() 4.7.3 ภ)/*! *Eb REภAE1ภ*E-P3$) / ภ/  / "  & , #8ภ/ 3-

"+ ภ,4()

"+ ภ, = 5"  "  & ,ภ/%* # "+ ภ, C6H12O6 = "  (6C + 12H + 6O) 4.7.4

ภ)/*! *Eb REภAE1ภb E  145


Chemistry for Engineers

Stoichiometry

+(%" % %&'-"#+  "    ! STP 30"+ ภ, (%* W V N n= = = M 22.4 6.02 Ă&#x2014;10 23 .! / " (W)  +  (n) -.    ! STP (V) -. 30"+ ภ, (N) # (#-! 3- "+ ภ,4() 34()ภ#"$ ( ภ!"ภ%/ +  #4 4.7.5 ภ)/*! *Eb REภAE1ภeภ+R)  +(% ภ   " % %&'-"#+  "    + ภ, 3- " + ภ,4() ภ3ภ*% $0"*05ภ+ ภ,+(% ภ  4() 4.7.6 ภ)/*! *Eb REภAEC*+*%-T m ภ3ภ30" "+ ภ, ()"" &ภ #8(% !ภ#" )" % $0" " + ภ,+(%ภ1ภ@ +(% /%  ภM (3,( .ภ9 !( 3,( (.( !  ! *  ))

3#*-+G. 4.7 ภ0-( "   H = 1, S = 32, O = 16 3- ภ. "+ ภ, H2SO4 . " H2SO4 1 + ภ, . " H2SO4 10 + ภ,  ภ. "+ ภ, H2SO4 = (2 Ă&#x2014;1) + 32 + (4 Ă&#x2014;16) = 2 + 32 + 64 = 98 3- . " H2SO4 1 + ภ, = "+ ภ, H2SO4 Ă&#x2014;1.66 Ă&#x2014;10-24 g = 98 Ă&#x2014;1.66 Ă&#x2014;10-24 g = 162.68Ă&#x2014;10-24 g 3- . " H2SO4 10 + ภ, = 10 Ă&#x2014;98Ă&#x2014;1.66 Ă&#x2014;10-24 g = 1626.8Ă&#x2014;10-24 g 3-

4.8

ภ)/*!Rภ+*ภ#b E

+  -#" !)"%(  #-! +(ภ0-(-) l(8 1 +  ภ/()",J 6.02 Ă&#x2014; 1023 ,J 6.02 Ă&#x2014; 1023 . +"ภ+( (AvogadroÂ&#x192;s number)

 146


Chemistry for Engineers

Stoichiometry

E-.X_ภ:3 ,#Z3-3G-YZ 1. "   Na = 23 $)  Na -%ภ23 g 3  Na ภ! 

Na -%ภ23Ă&#x2014;1.66Ă&#x2014;10-24 g 3  Na = 1  

Na -%ภ23

(%%* Na 23 g 3  Na = 2.

23 23 Ă&#x2014;1.66 Ă&#x2014;10 â&#x2C6;&#x2019;24

 

1 23 â&#x2C6;&#x2019;24 = 6.02 Ă&#x2014;10 1.66 Ă&#x2014;10

 

g 3  Na =

"   Al = 27 $)  Al -%ภ27 g 3  Al ภ! 

Al -%ภ27Ă&#x2014;1.66Ă&#x2014;10-24 g 3  Al = 1 Al -%ภ27

g 3  Al =

(%%* Al 27 g 3  Al =

27 27 Ă&#x2014;1.66 Ă&#x2014;10 â&#x2C6;&#x2019;24

1 23 â&#x2C6;&#x2019;24 = 6.02 Ă&#x2014;10 1.66 Ă&#x2014;10

 

 

 

3.

"+ ภ, H2SO4 = 98 $)  H2SO4 98 g 3  H2SO4 ภ!+ ภ, H2SO4 -%ภ98Ă&#x2014;1.66Ă&#x2014;10-24 g 3  H2SO4 = 1 + ภ, 98 g 3  H2SO4 = + ภ, H2SO4 -%ภ98 â&#x2C6;&#x2019;24 98 Ă&#x2014;1.66 Ă&#x2014;10 1 23 (%%* H2SO4 98 g 3  H2SO4 = + ภ, = 6.02 Ă&#x2014; 10 1.66 Ă&#x2014;10 â&#x2C6;&#x2019;24

4.

"+ ภ, C12H22O11 = 342 $)  C12H22O11 342 g 3  C12H22O11 ภ!+ ภ, C12H22O11 -%ภ342Ă&#x2014;1.66Ă&#x2014;10-24 g 3  C12H22O11 = 1 + ภ,

342 + ภ, 342 Ă&#x2014;1.66 Ă&#x2014;10 â&#x2C6;&#x2019;24 1 23 (%%* C12H22O11 342 g 3  C12H22O11 = â&#x2C6;&#x2019;24 = 6.02 Ă&#x2014;10 + ภ, 1.66 Ă&#x2014;10

C12H22O11 -%ภ342 g 3  C12H22O11 =

3ภ1 T 4 3 -9"# $)%! "   lภ% m +(-) %"  "%* #ภ%/

%"  "  -. "+ ภ,)" 3 30",J = 6.02Ă&#x2014;1023 ,J  

 147


Chemistry for Engineers

ภ/ 1

+ 

- $

1

Stoichiometry

+ + ภ,

%ภ"  ' (-#"*  .!) ภ,J30" 6.02Ă&#x2014;1023 ,J*"# l+ m # ("ภ%/0"# l+-m 2!) ภ30" 12  * .!ภ0-( 1 +  = 6.02Ă&#x2014;1023 ,J)" 30",J% " % %&'ภ%/ "()" (%%* l+ m 34% %&'ภ%/ "()"  1 +  = 6.02Ă&#x2014;1023 ,J (  , + ภ, , 4 Â&#x201E;Â&#x201E; T 4 #*ภ%/ ,-J , " (% T 4 #*ภ%/$ 1 +  = M g (M = "  -. "+ ภ, -. "4 Â&#x201E;Â&#x201E; T 4 #*ภ%/,-J , " (% T 4 #*ภ%/$ 1 +  = 22.4 dm3 ! STP T *ภ%/ ,-J , " (% )  STP T *ภ%/$ ) ภ@

4.9

PRD,-.b E

/#   (,J . + + ภ, , +    + 4 ภภ0-( J +  +3 '33/ภ-)+( "# +  J ( # HCl 1 + + ภ, , He 1 +   , NH4+ 1 + 4 -.33/ภ+ +(4 #/ภ J 2!ภ*3 ) /"# +  J ( #

 148


Stoichiometry

Chemistry for Engineers

ภ@2ภ2 3 1 +( %!" & ,ภ2 3 1  3 4('4 1 +  -)(3ภ%*

+  +  + 

- $ - $ - $

1 1 1

+ + ภ, +   8 4 ภ  J  + 4  

4.9.1 )* "# $#%&P*G.b Eภ# *E,-." -%ภ%!"84 (%*  1 + + ภ,-%ภ=  1 +   -%ภ= -%ภ-%=ภ #1 HCl+ 4 1 +  Na

"+ ภ, (-#" ภ% )

"  (-#" ภ% )

"4 = 36.5 (-# ภ%"  ภ% )

1

+  -%ภ=

23

ภ%

NH4+ 1

+  -%ภ=

18

ภ%

J"  6ภ@ . J" !,-J 0OC " (% 1 /ภ -. 760 mm ) %\%ภ'  STP 4.9.2 )* "# $#%&P*G.b Eภ# 3,-.Mภo" ภ0-(4")(%* ภ@ ,ภ (30" 1 +  3    22.4   ! STP -.   #+ ภ@ ,ภ (3 #ภ%/ 22.4   ! STP 4 #"#ภ@%*3 + ภ,( 9ภ-.(-\# 1 +  3    22.4   %* *

# He(g)

1

+     = 22.4

  ! STP

O3(g)

1

+     = 22.4

  ! STP

C4H10(g) 1

+     = 22.4

  ! STP

 +R3A    #+  #ภ%/ 22.4   )4() oภ@ ! STP #%* 3)ภ%/ -" 9 -.J",-J " (%.! 8 4 #4() 4.9.3 )* "# $#%&P*G. 1/*b E, 1/*-AD), *E MEP 3  149


Chemistry for Engineers

n=

Stoichiometry

W V N = = M 22.4 6.02 Ă&#x2014;10 23

.! n

=

30"+ 

N

=

30",J (  , + ภ,, 4)

W

=

" (-#" ภ% )

M

=

"  -. "+ ภ, -. "4

V

=

  ภ@ (-#"   ! STP)

4.10 E#ภ:!P#*mY,-.b1+&Rภ+*ภ#b E +3 ' !/  33,4()(%* ภ. ภ0-(  #8-) )"$ "#( 30"  -.30"+ ภ,

ภ!,( ภ 3-) 0   / / +()-%ภn = N  ! +  

ภ3 30" 

ภ ! + + ภ, ภ3 30"+ ภ, ภ. $ ภ!"ภ%/" % %&'-"# n, W, V, N (-! +(ภ0-( %" %" -!-) )" 

%" ! -. # ภ0-( " )"$ "# ภ!+ ภ,

%"# # H2SO4 5 ภ% ภ!+  ภ!+ ภ, ภ0"-))" % %&'

n=

W V N = = M 22.4 6.02 Ă&#x2014;10 23

. $ ภ!"ภ%/& ,ภ/ +(ภ0-( ภ/-) )"$ "# & ,

# 8 ภ!+  ภ!ภ% ภ! 

ภ0"%)" % %&'

n=

W N = M 6.02 Ă&#x2014;10 23

 150


Chemistry for Engineers

Stoichiometry

3#*-+G. 4.8 ภ@2ภ2 3 1.5 +  3 ภ!+ ภ, -%ภภ!ภ%    ภ!  (ภ0-( "  O = 16)  1 ภ@2ภ2 3 1 +   6.02Ă&#x2014;1023 + ภ, ภ@2ภ2 3 1.5 +   1.5Ă&#x2014;6.02Ă&#x2014;1023 + ภ, = 9.03Ă&#x2014;1023 + ภ, ภ@2ภ2 3 1 +  -%ภ2Ă&#x2014;16 = 32 ภ%

ภ@2ภ2 3 1.5 +  -%ภ1.5Ă&#x2014;32 = 48 ภ%

ภ@2ภ2 3 1 +     22.4   ! STP ภ@2ภ2 3 1.5 +     1.5Ă&#x2014;22.4 = 33.6   ! ATP  2

N 6.02 Ă&#x2014;10 23 N = n Ă&#x2014; 6.02 Ă&#x2014;10 23

n=

N = 1.5 Ă&#x2014; 6.02 Ă&#x2014;10 23 = 9.03 Ă&#x2014;10 23 molecule Ans

W M W = nĂ&#x2014;M n =

W = 1.5 Ă&#x2014; (2 Ă&#x2014;16) = 48 g V n= 22.4 V = n Ă&#x2014; 22.4

Ans

V = 1.5 Ă&#x2014; 22.4 = 33.6 litre at STP

 151

Ans

! STP

3- 3-

3-


Chemistry for Engineers

Stoichiometry

MUVภ#C 4.3 1. 3 )%! -9ภ-%ภภ!ภ% .!-)  -9ภ0.384Ă&#x2014;1023   (3.56 ภ% ) 2. ภ@2 C4H10 1 dm3 !,-J " (%  6  "ภ!ภ% (2.6 ภ% ) 3. .!0 .* (-!-%ภ100 ภ% " -' /"#  0.2 #")#" +(*0-%ภ.**  #ภ!  (6Ă&#x2014;1016   ) 4. ภ/ (NH4)2HPO4 79.2 ภ% & ,4r+( 3 'ภ/ภ!+  (5.4 + ) 5. /(ภ@2 #4*  ((3 30"+ ภ,) !,( ((" & () ภ. 1 ภ% H2 . 2 ภ% N2 . 3 ภ% NH3 . 4 ภ% O2 ( / ) .) 6. 

"# X  Y 0-) ภ(ภ/ 2  ( !    Y2X3  Y2X $) 0.05 +

 Y2X3 -%ภ9 ภ%  0.10 +  Y2X -%ภ10 ภ% "   X  Y

#   0(%/ #( (40 , 30) 7. ภ/ (-! .! 0-) 4ภ"# 5 cm3 4*-%ภ 20.85 # H2 25 cm3 2!"%( !,-J " (% ("ภ% 30" "+ ภ, %* (208.5)

4.11 ภ)/*!bC+OQ"03R) MEP" ภR)  4.11.1 "03R)  =* (Chemical formula) : ภ,# %\%ภ'& , ! * .!('ภ/    /#  3  J . 1.  ## (Empirical formula) 2.  + ภ, (Molecular formula) 3.  +) (Structural formula) 4.11.1.1 "03-+G..G+ (Empirical formula)  $/ภ$ ! # 8 (%* 1.1 %*ภ/()"& ,4/) 1.2 % #"# !030"  & , ! 'ภ/%* 1.3 % #"# !030"+   & , ! 'ภ/%* 1.4 % #"# !0 " ภ% & , ! 'ภ/%* 1.5 ' 29 '+( "& ,'ภ/ 4.11.1.2 "03b REภAE (Molecular formula)  $/ภ$ ! # 8 (%*  152


Chemistry for Engineers

2.1 2.2 2.3 2.4 2.5

Stoichiometry

%* 1 + ภ,ภ/()"& ,4/) #ภ! 

%* 1 + + ภ, ภ/()"& , #8#ภ!+  

"+ ภ, ภ ! / "  & , #8 ! 'ภ/ ' 29 '+( "& ,'ภ/  ## E#ภภOภ"03b REภAE 1. ) /& , ! 'ภ/%* 2. -% #"+( " #& , ! 'ภ/%* 3. -% #"+(30"+  #& , ! 'ภ/%* 4. - ## 5. ) / "+ ภ,%* (+3 '3/ภ+( -./ภ+( ) ) 6. )  ( ##) n = "+ ภ, .! /# n ภ9 # n )4 " 9/ ภ93 / + ภ, 7. ภ- + ภ,ภ@2 +(+3 '/ภ  ภ@2 ! ) 0 ภ ภ%(   ภ@2 !4()3ภ ภ  -))ภ1+"ภ +( +()-%ภ"# -#3"G*bC+ 3 = -#3"G*bC+b REภAE

4.11.1.3 "03b).". (Structural formula)  $/ภ$ ! #8 (%* - .ภ%/ + ภ,) 2.1 T 2.5 & , ! 'ภ/%*  #  3%( ภ%#4 3#*-+G. # ภ(*0) (Acetic acid)  + ภ,ภ(*0) . C2H4O2  ##ภ(*0) . CH2O  +)ภ(*0) . CH3COOH ( +)##) -.

 153


Chemistry for Engineers

Stoichiometry

3#*-+G. 4.9 ภ/& , Ca  X  "+ ภ, 160  Ca -%ภ25% 3- + ภ, ภ/* (ภ0-( "   Ca = 40, X = 60)  % #"+( " Ca : X = 25 : 75 25 75 % #"+(30"+  Ca : X = : 40 60 = 0.625 : 1.25 =1: 2 (%%*  ##* . CaX2 ( ##)n = = (CaX2)n [40+(2Ă&#x2014;60)]n = (40+120)n = n = (%%*  + ภ,* . (CaX2)1 =

"+ ภ, 160 160 160 1 CaX2

4.11.1.4 ภqCX+ ภ0"- %* /%*-% #"+(30"+ ภ)" /"#      %ภ/"# %( 30/ภ4 # /"#3^(   #4 ภ^(   *3 0-)0 /( .!44() (%%* .!/    3")-%ภ(%* 1. $)   < .2 -)^( 2. $)   > .8 -)^(* 3. $)#-"# .2 $ .8 -) ^(  # 0-)  30" 9 4()+(  %"  !) !,(% #",(%*- ( - 30" 9 !) !,(  ) 3.1 .!-)4() 30" 9 -.4()    2! < .2 -. > .8 )"3^(

 154


Chemistry for Engineers

Stoichiometry

MUVภ#C 4.4 1. ภ/ ! ภ@2 (-! ภ/()" C 75%, H 25% +( " "%("

-# ! STP 4() 0.7143 g/dm3 3- + ภ, (ภ0-( "  C = 12, H = 1) +3 ')*4 #4()ภ0-( "+ ภ,* +(   #ภ0-("

" ( -# ! STP -) 2!" -# " % %&'-"# "ภ%/   ) /-"#   22.4 dm3 ! STP (-. 1 + )  " #4 %!. /"# 1 +  -%ภ#4 ภ934() "+ ภ,%* 2. .!-)" )ภ%/ภ@22! 4r4(('& , X 2!    60 cm3 ภ"#4()4 & , X    30 cm3 ภ@24r+( 3   90 cm3 3- 4r4((' & , X (ภ0-( "  H = 1) ภ0-(  4r4(('& , X . XaHb  ภ ! ภ(* . X H â&#x2020;&#x2019; X + H 3. & ,   2.5 g 5ภ ภ(ภ42('   2.949 g 3- ## ภ42('* (ภ0-( "   U = 238, O = 16) 4.11.1.5 ภ)/*! *ERW-+EP1ภ"03 E#ภOภ)/*! 1. - "ภ/ 1 +  - "& , ! 'ภ/%* 1 +  2. /-) "ภ/%*  100 a

b

â&#x2C6;&#x2020;

2

2

3#*-+G. 4.10 3- ' 29 '+( " O  H2SO4 (ภ0-( "   H = 1, S = 32, O = 16)  "+ ภ,

" O  1 +  % & , O

H2SO4 = 2(1) + 32 + 4(16) = 98 = 4(16) = 64 g

"O1+  = Ă&#x2014; 100

"+ ภ,H 2 SO 4 64 Ă&#x2014;100 = = 65.31% 98  155


Chemistry for Engineers

(%%* H2SO4 ภ/()" O

= 65.31%

Stoichiometry 3-

MUVภ#C 4.5 3- ' 29 '+( "*0 Na2CO3 .10H2O (ภ0-( "  Na = 23, C = 12, O = 16, H = 1)

4.12 " ภR)  (Chemical equation)  ภ   (-) )34()+(   ภ* (Chemical equation) # ภ !ภ@24r+( 3 (H2) (4M4()  H2 0 ภ ภ%/ O2 ภ  ! ภ(* . *0 (H2O)  ภ   !( ภ * 4()  2H 2 + O 2 â&#x2020;&#x2019; 2 H 2 O # .!-  +  ภ*"# l 0 ภ ภ%/m  #ภ "# l 0-) ภ(m     !# 2)ภ )  %* )2! ภ"# $ (reactant)  ! ภ( "ภ ภ"# %"&' (product) %"  !#-)   ( * / Q (coefficient) +(# !  1 34 # ภ0ภ%/4") (%%* ภ* 3- $ ภ,# %\%ภ'-.  !)   ภ    ! ภ(* .!3ภ ภ   4 # ภ)  - #-. 0  (8 (%%*30"   & , # ( !# %*()ภ3 #ภ% ภ"#  ภ5"#" (balanced equation) $) /    %* %* )5 J%K' 3  ภ%* ) !%4 #(,* ภ# 3ภ%*3(, ภ+(##%  & Â&#x2039; ! 0-)  ,ภ ( !# #()ภ  30" #ภ% ภ# %  & Â&#x2039;-)  ภ !  4 ## ! (  # 2H2O - $ *0 2 + ภ, #" 3H2O - $ *0 3 + ภ,  ) 3#*-+G. 5.3 ภ(, ภ ภ ภ 54- )   (CH4)

  #"ภ/ !0%\ !#ภ@2&  .!$ภ54- )ภ3-)ภ@2 '/4(ภ42(' (CO2) 4*0 (H2O) (%%* ภ%* ) !%4 #4()(, 3 

CH 4 + O 2 â&#x2020;&#x2019; CO 2 + H 2 O  156


Chemistry for Engineers

Stoichiometry

ภ(, ภ%* ) -) .ภ(,& , ! # ( ("ภ% #()ภภ#  !* . C  H 2!/ o %* ) CH4 #"5 J%K'/ C  CO2  H / H2O 3(,30" C ภ# )"  ()"ภ(, H -)% ภ"# CH4 1 + ภ,  C 1    CO2  C 1   %  & Â&#x2039; %*3 #ภ%. 1  # CH4  H 4    !*0 ! ภ(*  H  2   $)-) %  & Â&#x2039;*0  2 34() H %*() ภ #ภ% (%*

CH 4 + O 2 â&#x2020;&#x2019; CO 2 + 2 H 2 O

( ภ !(,/#")

 ภ !4()  O 4 # #ภ% %*) +(5 J%K'  O "  4 %" 2! ภภ"# O  %*

)# 2 %" (%%*3 )#  2 %  & Â&#x2039;-) O2 !  %* )

CH 4 + 2 O 2 â&#x2020;&#x2019; CO 2 + 2 H 2 O

( ภ !(,# /')

0 4.1 1ภ" ภCAEME*,-.eภ+ภR\Y  R ภR,+D$,-.b REภAE /OR[*G 1/* -P3- Aภ-P3- /eภ ++#.). RGRC bC+#*Y+ /O" ภCAEME* RE,"# P"%sRWRE, 1/*-+"AC

ภ(, ภ+(" &) )3%( ภ(,// 5 ($ภ(trial and error) %**) " &(,   # ( #ภ%4+(%/#%  & Â&#x2039;  " 30  " &*)4()(ภ%/  ภ  #"-\#

 157


Chemistry for Engineers

Stoichiometry

$ ภJ   !# ภ %ภ(4")" 9/ +() (g), (l), (s)  (aq)  $ !  ภ@  -" 9 *0  0(%/ (%%* ภ !(,) ) .! # /'3 (%*

CH 4 ( g) + 2 O 2 ( g) â&#x2020;&#x2019; CO 2 (g) + 2 H 2 O(g) ภ(J"/#ภ 0 ภ /ภ # ,-J -. " (% %ภ%\%ภ'%* 8 4"))/ -.)#ภ # .!-  â&#x2C6;&#x2020;   ภ%/ ภ  !

))" )

0 4.2 0M"C.)* M3ภ3G.,-.3#*RE,ภ/ภ#CEG.,-.%3AO"03 ภ#3#*RE,"# P"%s-+0G"03 O"#.Rภ3*G 1/*-P3- ,-.%3AM3GEPQCO"03 )GRGภ#\E)0!,-.)G"# P"%ภs #3#*RE,ภ/ภ# CEG.,-.%3AO"03#Z

MUVภ#C 4.6 1.CAE" ภ3G-YZ

_Na(s) + _ H 2 O(l) â&#x2020;&#x2019; _NaOH(aq) + _H 2 (g) _C 2 H 4 (g) + _ O 2 (g) â&#x2020;&#x2019; _CO 2 (g) + _H 2 O(g) _Al(s) + _ HCl(aq) â&#x2020;&#x2019; _AlCl 3 (aq) + _H 2 (g) 4.12.1 E#ภOภR,+" ภR)  1. )  ภ  3ภภ ( ! ภ(*3 

 158


Chemistry for Engineers

Stoichiometry

2.  ! ) 0 ภ ภ% ( %* )) 4") ()2) ภ4") ภ +(-) -%"ภ*4% !4()3ภ ภ  (5 J%K')  %* ) â&#x2020;&#x2019; - # -. 5 J%K' (Reactant) (Product) 3. (, ภ +(- %"   -)%\%ภ'-.  .! 0-)30"   # & ,5 J%K' #ภ%/ %* )

4. .!-) ภ " -  !*   ($-.J" ! ภ!")()" $) 9 3# (s) 4")) 8 %* $)  -" 3# (l) 4")) 8 %* $) ภ@ 3# (g) 4")) 8 %* $)  ! *0  %" 0 3# (aq) 4")) 8 %*  ภ     3 0-)  / ! #4*. 1. ( 0 ภ   ภ%  ( ภ(*-%3ภ ภ    2. 30"+   ! 0 ภ ภ%( 30"+  ! ภ(* 3. 30",J  ! 0 ภ ภ%( 30",J ! ภ(* 4. "  ! 0 ภ ภ%(  " ! ภ(* 5. $) ภ  ภS: 3 /  ()" 3#*-+G. 4.11 ภ  ภ  3ภ ภ   ## 2  J . )ภภ (combination reaction)  )ภภ" (decomposition reaction)

 159


Chemistry for Engineers

Stoichiometry

0 4.3 ภR\bEPM ภRR]+ -P3- M ภRR]+ /eภ +ภ#b REภAE O2 1ภ-ภXRภCRW,-.M,[.Y---ภ)T- MgO

2Mg(s) + O 2 (g) â&#x2020;&#x2019; 2MgO (s)

0 4.4 ภ"E+3#*,-.b]RC+ R-Y]C& (Sodium azide NaN3) OQOcA.E D#+O c+3& R T-c0ภ1ACPภ+O"D*PR P" NaN3 1P"E+3#*OMภo"Yb3R1 N2 -+G.*CR[* MEP/Oc.A E ,++3#*--ภ 160


Chemistry for Engineers

Stoichiometry

2NaN 3 (s) → 2Na(s) + 3N 2 (g) 4.12.2 ก)/*!1ก" กR)  ก0"-" % %&' #8 ! ก!")ก%/ ก   %*#+ 

"    ! ก@2 30",J  $30"  -!3กก -! 2! / )" ก0"3ก ก3 ก!")ก%/ ก  1  ก -.- ก 33 ก!")ก%/ # 8  2  ( -. กก"#ก94() 2! #ก3 .*6ก0" )ก%  # ก #ก%/) 9ก) ( 4.12.2.1 ก)/*!Rก+*,-.ก# 1 " ก +3 '33ก0-( ก-) -.4 #ก0-(ก94() 2!$)4 #ก0-(-) %*ก )  กก#) %*(, ก )"3040" +( %!" 8 4 +3 '3ก0-( (-!-) (  ( (") )"$

 .! 8 ! -. ก0" )%  ก!"ก%/+  #"-\#3 3 o  !+3 '$  !ก0-(-) )"030"+   /% #"ก% .! #+  

" -  30" ! ! )ก4() 3 -94()"# ก /30"+  ) (3ก ก (%%* ก !$ก ) ! (,)" 33 $0 0"4()#$ก ) ,-%ก กK' %!" 8 4 0-%/ก0"3ก ก4()(%* 1.  ก-)$ก ) ( 0-)(,) 2.  3 o !+3 '$  !+3 'ก0-( -) 030"+ 3ก ก

 /% #"ก% 3.  #+   " -  30" ! ! )ก4() ก3ก30"+(ก /% #"+ )" % $ 34()3กก / /%\\% 4 ' 3#*-+G. 4.12 5+  2   (KClO3)   #( 33 %"-)+  2 4(' (KCl)  4()ก@ก2 3 (O2) 22.4   ! STP

 161


Chemistry for Engineers



Stoichiometry

 ก( ก  4()(%* : 2KClO 3 (s) → 2KCl(s) + 3O 2 ก@2ก2 3 22.4   ! STP = 1 +  3ก ก 4() O2 3 +  )) KClO3 = 2 +  4() O2 1 +  )) KClO3 = 2 × 1 = 2 +  3

KClO3 1 +   " = 39 + 35.5 + 3(16) = 122.5 ก%

(%%* ))+  2   (KClO3) = 2 ×122.5 = 81.6 ก% 3- 3

3#*-+G. 4.13 .! 5 ' " (II) ก42('3- (4()ก@ก2 3 11.2 ก/ก' (2

 !,-J " (%  6  ก ก   (%* 2HgO(s) → 2Hg(l) + O 2 (g)

" ' " (II) ก42(' !)  #4 (ก% )  %" !+3 '$ . HgO %" !+3 'ก0-(-). O2 + HgO 2 3ก ก = 1 +  HgO = 2 +  O2 + O 2 1  W HgO = 2 V O     2 M  22.4  W = ? ก% , M = 216.6 , V = 11.2 dm3 W 11.2 ∴ = 2× → W = 216.6 g 216.6 22.4 (%%* )) HgO 216.6 ก%

3- MUVก#C 4.7 1. *0 %ก  (C8H18) .!$ก 54- )# /' .! ' % #"+(+  ! 0  ก  (ก%  C8H18 : O2 = 1 : 12.5 $)) O2 4 67.2   ! STP *0 %ก $ก 54- )4ก!ก% (27.36 ก% ) 2. .! 5 ก 2 '/  (MgCO3) 3 %"  ก 2 ก42(' (MgO)  '/4(ก42(' (CO2) $)5 -"# MgCO3  MgO = 8.00 ก% .!04 53 %"# /' ก"#4()ก@2 CO2 1.12 dm3 ! STP 5 *ก# 5  MgO #ก!ก% (3.8 ก% )  162


Chemistry for Engineers

Stoichiometry

3ก) ก5 *0 % *0 % 5 dm3 3 )

   ( (C2H5)4Pb 4 cm3

   ( " -# 1.66 ก% /cm3  ก   !)    ( (%* 4C 2 H 5Cl + 4NaPb → (C 2 H 5 )4 Pb + 4NaCl + 3Pb $) )ก  *0 % 100 dm3 3 ))  4(' (C2H5Cl) ก!ก% .! 

   (-)( (106.1 ก% ) 4.12.2.2 ก)/*!1ก 1 " ก M3Gก/C"3#Z.3O 2 QC ก ! ก    %* ก!")ก%/ 1  ก  #+3 'ก0-(  %* ) ! )0"-) 2  ( 3,#กก"#กก ! ก!")ก%/ 1  ก ก0-( %* )-)   ( (" ก !+3 'ก0-( %* )-) 2  ( 33/#  2  J . ก. $ ก31 (1$ 2 6  $ 3)กก 1  -%3ก ก ( ก   /'3 4 # ( -.# ก*3(6$ 6 (ก7231!*3 %"&'

. ก$ ก31 (1$ 2 6  1 กก  -%3ก ก ( ก   /'  6 1 /0=ก(612 ก (-!3 -.# (6123 " 0%\

กก"# ก"# ก31  (limiting reagent) (6*3 %"&'

ก0"3,#ก  ! * ) 33ก กก#"# ()- ( -%3ก%*3 0 !)- (40" 5 J%K' 

)ก 3.

"A  ก   !ก0-(  %* )-) 2  ( 0"4()(%* ,#ZMก 0"ก#"#()- (4 ,#Z"-. 0 !)- (4 0"5 J%K' !+3 '$ +(030"+   / /ก% 2! .! #+   " -  30" ! ! )ก4() 3#*-+G. 4.14 .! 5+-   (Ag) 4.32 ก% ก%/52% M' (S) 0.64 ก% & ,( -.3ก ก   -.ก! ก%

 3ก+3 '  ก4()  2Ag (s) + S (s) Ag2S (s) 3ก ก ) Ag 2×108 ก% (2 + ) )) S = 32 ก% (1 + ) 32 × 4.32 ก%

$)) Ag 4.32 ก%

)) S = 2 × 108  163


Chemistry for Engineers

(%%* Ag 4.32 ก% 0 ก (ก%/ S 4 # & ,( -.-%3ก ก ( ก   /'

= 0.64

Stoichiometry ก%

3-

3#*-+G. 4.15 ก5 Freon 2!) *0 ) 9 (%( ก 3CCl 4 + 2SbF3 → 3CCl 2 F2 + 2SbCl 3 .!) CCl4   30.3 ก% 5 ก%/ SbF3 17.9 ก% 34() Freon (CCl2F2) ก!ก%

ก0-( "+ ก, CCl4 = 154 , SbF3 = 179 , CCl2F2 = 121 ก. 12.92 . 18.15 . 22.4 . 24.2  +3 'ก0-(  %* )-) 2  ( . CCl4  SbF3 (%%*3 ) 3 ก#"#()- ( )"3040"- CCl2F2 (Freon) ก -"#()- ( 3ก ก ) SbF3 2×179 ก% (2 + ) )) CCl4 = 3×154 ก% (3 + ) 3 × 154 × 17.9 $)) SbF3 17.9 ก%

)) CCl4 = = 23.1 ก%

2 × 179 $)) SbF3 17.9 ก% 3 )) CCl4 23.1 ก%  # CCl4  30.3 ก% ("# -.  SbF3 )- ( -)040"- CCl2F2  0" CCl2F2 + CCl 2 F2 3 3ก ก = + SbF3 2

3 1 +  CCl2F2 = +  SbF3 2

 W1  3 W   CCl 2 F2 =  2 SbF3 2  M2   M1  W1 = ? ก% , M1 = 121 , W2 = 17.9 ก% , M2 = 179 W 3 17.9 ∴ 1 = × → W1 = 18.15 g 121 2 179 (%%* 3  Freon 4() 18.15 ก%

 164

3-


Chemistry for Engineers

Stoichiometry

 ก0" ! ก!")ก%/ %* ) 2  ( $) .ก)ก0-( 5 ( 3 4()0 / !4 #$ก ) 2! %ก3 #0 / %*- (()" # ก !) CCl4 0"-   CCl2F2 34()0 / #.! !5 (  #0 / ก ,  ,    ()"

MUVก#C 4.8 1. 3กก" -'ก/ X /"#ก/()"ก0 $% 40 ' 29 '+( " ! -.ก%* ก2 3 (%%* $))ก0 $%ก2 3# 10 ก%  0  ก  ก% 34() X # กก!ก% (16.67 ก% ) 2. .! 0 ก #4*-)(,)" 3 )) CaCl2 ก!ก% 334() AgCl 10.0 ก%

AgCl + Ca(NO3)2 (3.87 ก% ) CaCl2 + AgNO3 3. 3ก ก   Zn (s) + H2SO4 (aq) ZnSO4 (aq) + H2 (g) 3 )) *%ก-%กก!ก% ก  H2 6.9 dm3 ! STP ( "   Zn = 65.4 ) (20.1 ก% ) 4. 3ก ก   !ก0-(-) (M . +- !  "  = 30) 2 MCln + n H2SO4 M2(SO4)n + 2n HCl (g) /"#$))ก/4(' (MCln) -%ก 3.44 ก% 0 ก  34()ก@24r+( 3 4('-%ก 2.92 ก% # n 3  #( (n = 4) 4.12.2.3 ก)/*!Rก+*,-.ก#" ก กก*G 1 " ก %ก ก  (%ก#"*3 ก ( # .!ก%4 +( %*# ก  " ก%

%* # 2 %*#*4 ก*ก3ก3(, ก # ก)" % ) 0-) ก %*- ( -#%*(,// # .!()" +(- ! 0-) ! .!  ก )()"ก% -%3ก !(, ก// # .!)" 33030"+  !+3 '$  !+3 ' ก0-(-) 2!# # ก  /% #"ก% .! #+   " -  )"3 0" ! ! )ก4()  ก0" ! ก!")ก%/ ก กก"# 1  ก ก.  ก( ก   ! ก (* # ก  -)$ก ) . 0 ก %*- (%*-)(,// # .!

 165


Chemistry for Engineers

Stoichiometry

. 3ก ก !(,// # .! 030"+  !+3 '$  !ก0-(-)  / % #"ก% .! #+   " -  30" ! !+3 '$ 4() ก  ก !" # . ก 030"+ ก, ! ก ( ก   # .!ก% -) #ก% ก#"4()"# l !3)(, ก// # .! . !  ) - ,ก ก ( ก   // # .! 2! .! 0%*-) 30" #ก%ก934() ก !(,// # .!m

3#*-+G. 4.16 3ก ก  

2C(s) + O 2 (g) → 2CO(g) LL(1)

Fe 2 O 3 (s) + 3CO(g) → 2Fe(s) + 3CO 2 (g)LL(2) 3 ))'/ก!ก +ก% 4( "2' Fe2O3 100 ก +ก%

 .!3ก  ก ! ก!") 2  ก  !+3 '$ . C  !+3 'ก0-(-). Fe2O3 # ก (%%*3 )(, ก-) # .!ก# )"330"- ! ! )ก 3ก ก (1)  (2) 3 -94()"# CO # %* ก (1)  (2) ("#  ! 0-) ก ( ก   # .!ก%4 (%%*3 0 ก-)(,// # .! +( 030"+ ก, CO -) #ก% (1) × 3 : 6C + 3O 2 → 6COLLL(3)

(2) × 2 : 2Fe 2 O 3 + 6CO → 4Fe + 6CO 2 LLL(4)  ก (3)  (4)  CO #ก% 3(,// # .! + C 6 6 3ก (3),(4); = 1 +  C = +  Fe2 O3 + Fe 2 O 3 2 2  W1  6 W   C =  2 Fe 2 O 3 2  M2   M1  W1 = ? ก +ก% , M1 = 12 , W2 = 100 ก +ก% , M2 = 160 W 6 100 ∴ 1 = × → W1 = 22.5 kg 12 2 160 (%%* ))'/ 22.5 ก +ก%

MUVก#C 4.9

 166

3-


Chemistry for Engineers

1.

Stoichiometry

30" " KMnO4 ! ))0-%/ 0 ก  ก%/ก( HCl ! 30" ก .!-)4() Cl2   ( !3 0 ก  ก%/ก@2 H2 !4()3ก Mg 10 ก% 0 ก   ก%/ H2SO4 ! 3.3 !   ก (26.3 ก% )  ก ! ก!") . 2KMnO 4 + 16HCl → 2KCl + 2MnCl 2 + 8H 2 O + 5Cl 2 LL(1)

Cl 2 + H 2 → 2HCl LL(2) Mg + H 2 SO 4 → MgSO 4 + H 2 LL(3)

2.

ก  KMnO4 3  4()   ก 2 %*  (%* MnO 2 + 4KOH + O 2 → K 2 MnO 4 + 2H 2 OLL(1)

3K 2 MnO 4 + 4CO 2 + 2H 2 O → 2KMnO 4 + 4KHCO 3 + MnO 2 LL(2) $) )ก KMnO4 100 ก% 3 ))ก@2 O2 ก!ก% (30.4 ก% )

4.13 ก$ ก%& 'ก T- ก$ก  !ก( )(" % %&' -"#  ก@ ! 0 ก  (ก%   ก@ ! ก (3ก ก    ,-J  " (% ("ก% l% #"-"#  ก@ ! 0 ก  (ก%    ก@2!4() 3ก ก   !,-J " (% ("ก% 34()  30" 9  %") 8 m # % #"   N2 : H2 : NH3 = 1 : 3 : 2 2!   %"# !0 ("# 4  ก1 ก',2ก

4.14 ก$ ก  T-  !) ก  )(" % %&'-"#   ก%/30",Jก@ J )" (%,-J ("ก% lJ ),-J " (% ("ก% ก@ ,ก ( !    #ก% # 3 30" ,J  30"+  #ก%m

 167


Chemistry for Engineers

Stoichiometry

* % " ภ@ ,ภ (4 #"#3 + ภ,(-\# -. 9ภภ9  !J",-J  " (% ("ภ%    #ภ% 3 ) 30"+ ภ, -. 30"+  #ภ%

# ! STP $) ภ@ SO2

1     N + ภ, ภ@2 CH4 1    ภ9 )  N + ภ, # ("ภ% ภ1+"ภ+( ($" % %&'    ภ%/ + ภ, -. +  2!   ภ4()(%* V â&#x2C6;? N or V â&#x2C6;? n

4.15 ภP+Aภ3&ภ;-b*ภbCภ#" ภR)  ภ1+"ภ+(  $ !  ภ@ ! 0 ภ (ภ%-) 30" + ภ,4() ภ9 $ !30"+ ภ, ! 0 ภ (ภ%-)   4() # ("ภ% ภ. $)  ภ   !(,)"  $ !30"+  ! 0 ภ (ภ% -)    4() %   %"  !(30"+ ภ,# (  ภ@%*8()" # N 2 (g) + 3H 2 (g) â&#x2020;&#x2019; 2NH 3 (g)

1 mole

3 mole

2 mole

1 cm 3

3 cm 3

2 cm 3

5J(4()(%*

 168


Chemistry for Engineers

Stoichiometry

. $)   ภ@ ! 0 ภ (ภ%   ภ@ ! ภ(3ภ ภ  2!4() 0-)  # !0)"  $ !-) + ภ,-.+  04  ภ ! (,)"4() # A(g) + B(g) â&#x2020;&#x2019; C(g)

20 cm 3

30 cm 3

20 cm 3

2 cm 3

3 cm 3

2 cm 3

2 mole

3 mole

2 mole

  ภ 2A + 3B 2C +, ภ1 ภ',2ภภ1+"ภ+( )4() oภ%/ !#$ภ@  #J ),-J " (% ("ภ% #%*

3#*-+G. 4.17 J ),-J " (%#-! ภ@r  1 dm3 ภ/4()"r  2.4 x 1022  

J )J" ("ภ%* 30"+ ภ,4r+( 3ภ@ 1 dm3 3 ภ!+ ภ, ภ. 2.4 x 1011 . 1.2 x 1022 . 2.4 x 1022 . 2.4 x 1044   ภ1+"ภ+( ภ@ #8J ),-J " (% ("ภ% .!   #ภ% # 3 30"+ ภ, #ภ%()" .! ภ@ He 1 dm3

 He 2.4 x 1022   (+ ภ,) ภ@ H2 1 dm3 3  H2 2.4 x 1022 + ภ, -----------------() 3#*-+G. 4.18 "(/-!/3,ภ@ภ2 3 "%( "ภ@ ,-J " (%4") ภ2 3ภ-) - ( )"#ภ@   )4 -),-J " (% ( "%( "   "  3 ภ! #ภ2 3

 169


Stoichiometry

Chemistry for Engineers

ก. #ก%

.

1 2

. 2 #

.

1 4

  ก1+"ก+( ก@ #8J ),-J " (% ("ก% .!   #ก% # 3 30"+  #ก%()" = +  CH4 +  O2

 W1  W   O 2 =  2 CH 4  M1   M2  W1 = ? , M1 = 32 , W2 = ? , M2 = 16 W W W 1 ∴ 1 = 2 → 2 = 32 16 W1 2

" CH4 (W2) 3 

1 # " O2 (W1)--------------------------------() 2

MUVก#C 4.10 1. 3ก ก   #4* 2X2Y3(g) + 5Z2(g) 3Z3Y2(g) + ZX4(g) ก@ ! 5 J%K'3กก" 30 cm3  X2Y3  100 cm3  Z2   ก! cm3 !,-J " (% ("ก% ก. 40 . 45 . 55 . 60 2. .!0ก@ A 0 ก  ก%/ก@ B 4()ก@ C  ( (" +( 5ก ((%*  3R 3 (cm3)  3RET- (cm3) )#Z.  3* E#.RกCeก+ (cm3) A B A B 1 40 60 20 60 2 100 350 50 250 $)ก"%(  ก@ 0 !,-J " (% ("ก% ก. 3  ก( ก   ! ก (* . $)) B 150 cm3 0 ก  ก%/ A 30" ก ก  34()ก@ C ก! cm3  170


Chemistry for Engineers

Stoichiometry

4.16 ภ)/*!Rภ+*ภ#"EPE+   % (solution) : 5 .* (" !ภ/()" 3"/" (solvent)  0=ภ"/" (solute) 0 "/"ภภ3"/"#"/0=ภ"/" 0 /ภ #  -" -"  !   ภภ"#33%("#  %" 0  !  )ภ"#3  %"$ภ 0 "/"ภภ3"/"#"/0=ภ"/" 0 /ภ #  -"9 ,  -"-ภ@  ! $ ("ภ%/ 3  %" 0  !  $ #3ภ3  %"$ภ #  NaCl *0 *0 $  -" # ("ภ%/ (%%* *03 

%" 0  ! NaCl 9 2! $ #3ภ 3  %"$ภ  (-!8 33 $ 9  -" -. ภ@ ภ94() 33  %" $ภ ภภ"# 1  (ภ94()  #3 )  %" 0 ( ("ภ% 4.16.1 G*+,-.)* R, , +( %!" 8 4 3ภ0-(    %"$ภ -. %" 0 #  HCl 0.1 + /  ,  C6H12O6 0.02 + /ภ+ภ%  ) -#"" ) ) !)ภ% ภ4()ภ# ภ. + ' (Molar ; M) -. + /  -. mol/dm3 - $ 30"+  %"$ภ  1   #  HCl 0.1 + /  - $  1    HCl 0.1 +  + /  -#"" ) ) !*ภ%/,-J $),-J ! " ) )3 !4()" . +  (Molal ; m) -. + /ภ+ภ% -. mol/kg - $ 30"+  %"$ภ 1 ภ+ภ%

#  HCl 0.1 + /ภ+ภ% - $ *0 1 ภ+ภ%  HCl # 0.1 +  . ) -. ' 29 ' (%) /#ภ 3  J .

 171


Chemistry for Engineers

Stoichiometry

1. )+( " # " -. )+( " - $ " 100 -#"*0-%ภ#  HCl 30%+( " - $  100 ภ%  HCl # 30 ภ%

2. )+(   #   -. )+(   - $     100 -#"   #  HCl 30%+(   - $  100 cm3  HCl # 30 cm3 3. )+( " #   - $ " 100 -#"    #  HCl 30%+( "/   - $  100 cm3  HCl # 30 ภ%

)+( " -#"" ) ) !4 #*ภ%/,-J  # )+(    )+( " #   -#"" ) ) !*ภ%/,-J ภ3ภ*% -#"" ) ).!8ภ# -#"#")#" +( "-.+(    (ppm) - $ " 1 )-#"*0-%ภ-.  1 )-#"   #  Hg 2 #")#"+( " - $  1 )ภ%  Hg 2 ภ%

/ภ33ภ0-(-#"" ) )   / / # $) %"$ภ  )  # %" 0  ภภ"#  3.3 $) %"$ภ  ภ # %" 0  ) ภ"#  ) )  )

4.16.2 ภ1/*b E,-."O"EPE+ o-#" + /  $) /     " ) )  3- 30"+  4()(%*   Ă&#x2014; " ) ) 30"+  = 1000 VC n = 1000 V = cm3 , C = mol/l .! 3 30"+ #" ภ%/30"+ # # 8 !5# )" 34() 

 172


Chemistry for Engineers

n=

Stoichiometry

W V N VC = = 23 = M 22.4 6.02 Ă&#x2014; 10 1000

MUVภ#C 4.11 1. 30"30"+  NH3  #4* ภ.  NH3 0.1 mol/l , 200 cm3 .  NH3 3.4%w/v , 200 cm3 2.  ภ 2 4(' ) ) 0.5 mol/l 30" 500 cm3 3 4('4 #ภ!+  ภ. 0.25 . 0.50 . 1.00 . 17.75 4.16.3 PRD,-.ภ)/*!Rภ+*ภ#"EPE+ /#ภ 3  J ภ. ภ   +( -  3ภ9  -" ภ@  %" 0 ! - 

-  3ภภ 3.3 -  3ภภ5 -" ) ) )()"ภ% . ภ !-#"" ) ) - ! % -)  mol/l - ! mol/l -)  % . ภ0" ภ!"ภ%/ ภ  

4.17 ภR3+ "EPE+1ภ,-.M,[. ,-.RE* Mภo" +(09  -" -. ภ@30"-! #*0 -.  %" 0 ! - 

#"-\#3)%!*0-%ภ ! )ภ )"04*0 .!3ภ"$9 ( -" , ภ@) #ภ%/ "  (%%* l30"+ / , & Â&#x2039; # #ภ%/ 30"+  n () = n () W VC = M 1000

 173


Chemistry for Engineers

Stoichiometry

3ภ 3 -94()"#  %"# 3  ( . W, V  C 2!ภ0" +3 '3 ภ0-(-) 2 %" # ภ0-( W, V 0"- C 0-%/ W 33ภ0-(-) ) # $)  -"3ภ0-(  -) ) !-)  "ภ#+(  ()"" -# W =    Ă&#x2014; " -# ภภ@2ภ9 # ("ภ% 33ภ0-(    ! STP -)  $3 !   ภ@2-)  "ภ# -.30"+()  V VC = 22.4 1000 MUVภ#C 4.12 1. $)  ( (II) 4  # 3.31 ภ% )ภ   ( (II) 4  ! "

) ) 0.4 mol/l 34()    ภ! cm3 (M = 331) 2. $)ภr' 23.75 cm3 ()" /2 300 cm3  !4()3 " ) ) #( " -#ภr' = 0.8 g/cm3 , " -# /2 = 0.9 g/cm3 , "+ ภ,ภr' = 46 3. $) )ภ  +2 ( 4  (NaNO3) 100 cm3 +(-) !4()  +2 ( 4 0.023 ภ%  1 cm3 3 04()#4

4.18 ภR3+ "EPE+bC+ภ/OR1T-1. .! *0 (-. %" 0) 4 3 0 -)" ) )    !  #30"+ 4 # ! (%%* ภ0"3 (-%ภ30"+ ภ# *0 = 30"+ -% *0 C1 V1 = C 2 V2 MUVภ#C 4.13 1.

 HCl ) ) 0.2 mol/l # 500 cm3 $) )ภ  ภ( HCl -) ) ) 0.03 mol/l 30" 100 cm3 3 ))ภ( HCl 0.2 mol/l ภ! cm3 2.  NaCl ) ) 0.2 mol/l 30" 300 cm3 0  *03  1   )ภ /"# *0-%ภภ%  NaCl  300 cm3  ) ) 0.2 mol/l  *0-%ภภ%  NaCl  300 cm3  ! 3.3)" #  #4

 174


Chemistry for Engineers

3.

Stoichiometry

$) )ภ 0 H2SO4 ) ) 1 mol/l 30" 50 cm3 3ภ ) ) 4 mol/l 3 )ภ*030"ภ! cm3 5 ภ%/ภ(*

4.19 ภR3+ "EPE+bC+ภ\" "EPE+E+)* R, ,R,C*+ภ# .!0 ( ("ภ% ! " ) )   #8ภ% 5 ภ% 34() - # !" ) ) ภ#3ภ(

ภ0"%-%ภ!"# l30"+ ภ#-%5 ภ%3 ) #ภ%m n (ภ#5 ) = n (-%5 ) V1C1 + V2 C 2 + LLL = VC -. VC = V1C1 + V2 C 2 + LLL MUVภ#C 4.14 1. 3 )0ภ( HCl 0.5 mol/l ภ!  5 ภ%/ภ( HCl 0.1 mol/l ภ!   334()ภ( HCl 0.2 mol/l    2   2. $) )ภ3  ภ( HNO3 1 mol/l -)    14   +(ภ ภ( HNO3 15 mol/l 4ภ( HNO3 2 mol/l 30" 1250 cm3 3 ))ภ( HNO3 15 mol/l 30"ภ! 

4.20 ภRE+G*+)* R, ,,-."EPE+ #"-\#3 ภ !3ภ-#" )// # 8 -)  + /  -. 33 ! + /  -)  ) ภ0" ภ!"ภ%/ภ !-#"" ) ) #"-\# )))  ภ!"ภ%/"

-# 33, ภ0"ภ !-#"4()(%* dx mol/l = 10 M 3 d = " -# (g/cm ) , x = % , M = "+ ภ, * % *! 1. ภ ! %w/v  mol/l 4 # ))" -# (%%* x mol/l = 10 M 2. ภ ! %w/w  mol/l , d = " -# 3. ภ ! %v/v  mol/l , d = " -# ( %"$ภ)  175


Chemistry for Engineers

Stoichiometry

MUVภ#C 4.15 1. *0)  (-! " -# 1.13 g/cm3 /,"# ภ(2 ภ(CH3COOH) # 8%w/w *0) * " ) )ภ(2 ภ ( ภ! mol/l 2. *0)  ภ(*0) (CH3COOH) # 5%v/v $) (" ) )  mol/l 3  # #( 3. ภ (-!ภ"# ))ภ((  " (HNO3) 0.1 mol/l 30" 450 cm3  # -) /% ภ  #ภ((  " (ภ(4  ภ) ! (ภ4")(%* 70%(wt/vol) HNO3 density 1.4 g/cm3 3   !   " ) )  ! )ภ4()#4

4.21 ภ)/*!"EPE+1ภeภ+R)  )-%ภภ 0 ("ภ%/ภ0"3ภ ภ +( 3 o %" !+3 ' $  %" !ภ0-() -) 030"+   /% #"ภ% -%3ภ #30"+  3 -0 / ! )ภ4() 3#*-+G. 4.19 $)0 0.55 dm3  0.01 mol/dm3  Na2CO3  ภ( HCl 0.1 mol/dm3 30" 0.2 dm3 3 ภ( ภ (%* Na 2 CO 3 + 2HCl â&#x2020;&#x2019; 2NaCl + H 2 O + CO 2 4()ภ@2 CO2 ภ(*ภ!+   .!3ภ %* ) 2  ( . Na2CO3 ภ%/ HCl %*ภ3 )-ภ#"#() - ( )"30 !)- (40"30"+  CO2 0-%/ Na2CO3 n = VC (%%* +  Na2CO3 = 0.55 x 0.01 = 0.055 +  0-%/ HCl n = VC (%%* +  HCl = 0.2 x 0.1 = 0.02 +  3ภ ภ ) HCl 2 +  )) Na2CO3 = 1 +  $)) HCl 0.02 +  )) Na2CO3 = 1Ă&#x2014;0.02 = 0.01 +   176


Chemistry for Engineers

Stoichiometry

 #  Na2CO3 0.055 +  (%%* Na2CO3 3 -.  # HCl )- ( 30 HCl 4-   CO2 3ภ ภ) HCl 2 +  4() CO2 = 1 +  $)) HCl 0.02 +  4() CO2 = 1Ă&#x2014;0.02 = 0.01 +  0.01 +  3- (%%* 4()ภ@ CO2

MUVภ#C 4.16 1.

 NaOH ) ) 0.5 mol/l #30"-! 2! 30" !3 0 ภ   (ภ%/ HCl ) ) 0.2 mol/l 30" 100 cm3 $) )ภ NaOH ) ) 0.1 mol/l +(  3ภ ! #34()# ภ!,( ภ! cm3 2. .! 0 ภ  #4*-)(, BaCl2 (aq) + AgNO3 (aq)

Ba(NO3)2 (aq) + AgCl (s)

3 )) BaCl2 0. 5 mol/l    #( 334() ภ AgCl ภ(* 71.75 ภ%

ภ0-( "+ ภ, AgCl = 143. 5

 177


Stoichiometry