ࡱ> '` 09(bjbjLULU 4.?.?9 $L4L4L4L4l4$$E55555555DDDDDDD$Fh>ID55555D55D8<8<8<555D8<5D8<8<>>55 KL49>@D0$E>,558<55555DD8<555$E5555$$$$H$$$H$$$ Determining Reaction Rate, Order of Reaction and Rate Law Background The effect of concentration, temperature, and a catalyst on the rate of a reaction can be understood within the framework of the collision theory of reaction rates. Collision theory offers a simple explanation for how fast a reaction will occur - in order for a reaction to occur, reactant molecule must first collide. Not all collisions, however, will lead to products. In order for colliding molecules to produce products, the collision energy must exceed a certain critical energy level called the activation energy, for the reaction. If the activation energy is low, almost all colliding molecules will have sufficient energy to overcome the energy barrier for the reaction. These reactions will occur very fast. In contract, if the activation energy is high, only a small faction of the colliding molecules will have sufficient energy to overcome the energy barrier for the reaction. These reactions will occur much more slowly. The rate of a chemical reaction may depend on the concentration of one or more reactants or it may be independent of the concentration of a given reactant. Exactly how the rate depends on reactant concentration is expressed in an equation called the rate law. For a general reaction of the form A+ B ( C the rate law can be written as Rate = k[A]n[B]m where k is the rate constant, [A] and [B] are the molar concentrations of the reactants, and n and m are exponents that define how the rate depends on the individual reactant concentrations. The values of n and m must be determined by experiment not just by looking at the balanced equation. The rate constant for a reaction is not affected by reactant concentration, but is affected by temperature. The exponents n and m are also referred to as the order of reaction with respect to a particular reactant. In the above example, the reaction is said to be nth order in A and mth order in B. In general, n and m will be positive whole numberstypical values of n and m are 0, 1, 2. The reaction order for each reactant in the rate law determines how the rate changes as the concentration of the reactant changes. If a reactant has an order of zero, the reactant does not appear in the rate law and the rate is independent of it concentration. Increasing or decreasing the concentration of a zero-order reactant does not affect the rate of the reaction. When a reaction is first order for a reactant, the reactant appears in the rate law with an exponent of onethe rate is directly proportional to the reactant concentration. If the concentration of a first-order reactant is doubled, the rate will also double. For a reaction that is second order for a reactant, the reactant concentration appears in the rate law with an exponent of two. If the concentration of a second-order reactant is doubled, the rate of the reaction will increase by a factor of four. In this reaction, potassium iodate and sodium metabisulfite react to form iodine. The starch solution serves as an indicator of the end of the reaction by forming a deep-blue colored starchiodine complex. The reaction time can thus be measured by noting the time until the appearance of the blue color for each trial. The overall reaction occurs in a series of steps, as outlined below. Step 1: Formation of iodinate ions (IO3-) and hydrogen sulfite ions (HSO3-) Solution A: KIO3(aq) ( IO3-(aq) + K+(aq) Solution B: H2O(l) + Na2S2O5(s) ( 2HSO3- (aq) + 2Na+(aq) Step 2: Iodate ions react with hydrogen sulfite ions to produce iodide ions (I-) IO3- (aq) + 3HSO3- (aq) ( I-(aq)+ 3H+(aq)+ 3SO42-(aq) Step 3: In the presence of hydrogen ions (H+), the iodide ions react with excess iodate ions to produce iodine (I2). This is the kinetically slow step in the overall reaction. 6H+(aq) + 5I-(aq) + IO3-(aq) ( 3I2(aq) + 3H2O(l) Step 4: Before the iodine can react with the starch to produce a dark blue colored complex, it immediately reacts with any hydrogen sulfite ions still present to form iodide ions. I2(aq) + HSO3- (aq) + H2O(l) ( 2I-(aq)+ 3H+(aq)+ SO42-(aq) Step 5: Once all of the hydrogen sulfite ions have reacted, the iodine is then free to react with the starch to form the familiar dark-blue colored complex. I2(aq) + starch ( dark-blue colored complex Materials Potassium iodate solution, KIO3, 0.20 M Graduated cylinder, 10-mL Starch solution, 2% Graduated cylinder, 25-mL Sodium metabisulfite, Na2S2O5, 3.8 g Pipets Sulfuric acid solution, H2SO4, 0.1 M Hot plate Water, deionized Ice bath Balance Thermometer Test Tubes, 6 Timer or stopwatch Beakers, 50 mL, 6 Stirring rod Pre-Lab Calculations Determine the concentrations (M=mole/L) of both Potassium Iodate and Sodium Metabisulfite in each mixture and record answer in table. M1V1=M2V2 Show your work in calculations section. Procedure Solution ABeaker 1ABeaker 2ABeaker 3ABeaker 4ABeaker 5ABeaker 6APotassium Iodate Solution, 0.20 M5 mL10 mL2.5 mL5 mL5 mL5 mLDistilled or Deionized Water15 mL10 mL17.5 mL15 mL15 mL14 mLSulfuric Acid Solution, 0.1 M0 mL0 mL0 mL0 mL0 mL1 mLTemperature of Solution ARoom TempRoom TempRoom TempRoom TempRoom TempRoom Temp Solution BTest Tube 1BTest Tube 2BTest Tube 3BTest Tube 4BTest Tube 5BTest Tube 6BSodium Metabisulfite Solution, 0.20 M1 mL1 mL1 mL2 mL0.5 mL1 mLDistilled or Deionized Water4 mL4 mL4 mL3 mL4.5 mL4 mLStarch Solution3 mL3 mL3 mL3 mL3 mL3 mLTemperature of Solution BRoom TempRoom TempRoom TempRoom TempRoom TempRoom Temp 1. Control Reaction. Pour Solution 1B into Solution 1A. Stir. Carefully time the reaction with a stopwatch or timer. Record the time from when the two solutions are mixed until the appearance of the blue color. Determine Reaction Rate for Mixture 1. 2. The Effect of Concentration of Potassium Iodate upon Reaction Rate. Pour Solution 2B into Solution 2A. Record the time from when the two solutions are mixed until the appearance of the blue color. Repeat with Solutions 3B and 3A. Determine Reaction Rate for Mixtures 2 and 3. 3. The Effect of Concentration of Sodium Metabisulfite upon Reaction Rate. Pour Solution 4B into Solution 4A. Record the time from when the two solutions are mixed until the appearance of the blue color. Repeat with Solutions 5B and 5A. Determine Reaction Rate for Mixtures 4 and 5. 4. The Effect of a Catalyst on the Reaction Rate. Pour Solution 6B into Solution 6A. Record the time from when the two solutions are mixed until the appearance of the blue color. Note: Sulfuric acid is a catalyst for this reaction. 5. (Only if time allows) The Effect of Temperature on the Reaction Rate. Set up beaker and test tube of solutions like Control Reaction but put them in ice bath or water heated on hot plate before and after mixing. Record temperatures of solutions using thermometer. Record the time from when the two solutions are mixed until the appearance of the blue color. Determine Reaction Rates. Results Mixture 1Mixture 2Mixture 3Mixture 4Mixture 5Mixture 6Concentration of Potassium Iodate [KIO3] (M)Concentration of Sodium Metabisulfite [Na2S2O5] (M)Time (sec) Reaction Rate (M/sec)  Calculations for Table Analysis Questions Does the rate depend on [KIO3]? What is the reaction order for KIO3? Does the rate depend on [Na2S2O5]? What is the reaction order for Na2S2O5? What is the rate law for the reaction? Preparations 1. Prepare 100 mL of a 0.20 M sodium metabisulfite solution by dissolving 3.8 g of sodium metabisulfite in enough distilled or deionized water to make 100 mL of solution. This solution has a poor shelf life (about 12 months) and should be prepared fresh for the demonstration. 2. Prepare a 2% starch solution by first making a smooth paste with 10 g of soluble (potato) starch and 50 mL of distilled or deionized water. Pour the starch paste into 500 mL of boiling water while stirring. Stir until dissolved and the solution is clear. Allow the solution to cool to room temperature before use. Starch solutions have a poor shelf life and will form mold if kept too long. Fresh solutions work best. Use within one or two months. 9:;F: ; < = |   H I L M Jlghuuii]iNhJTnh=3OJQJ^J_H hYOJQJ^J_H huOJQJ^J_H hqhqH*OJQJ^J_H " jhqhqOJQJ^J_H hqOJQJ^J_H hlPOJQJ^J_H "hJTnhJTn5OJQJ\^J_H *hJTnh.a5CJ OJQJ\^J_H aJ $hJTn5CJ OJQJ\^J_H aJ *hJTnhJTn5CJ OJQJ\^J_H aJ :;F h;d'( 7$8$H$]gd 7$8$H$]gdy7$8$H$]^`gd7$8$H$]`gdY 7$8$H$]gdJTn7$8$H$]`gdu 7$8$H$gd=3 $7$8$H$a$gdJTn9(678JOPQRTUVZ^_cdoqrsvy{|}~ػػ{{{n\" jhyhyOJQJ^J_H hyH*OJQJ^J_H hyhyOJQJ^J_H hyhyH*OJQJ^J_H hhOJQJ^J_H " jhhOJQJ^J_H hH*OJQJ^J_H hhH*OJQJ^J_H hhH*OJQJ^J_H hyOJQJ^J_H hOJQJ^J_H $ Ȼخo_RohH*OJQJ^J_H hyhH*OJQJ^J_H hyhH*OJQJ^J_H hhOJQJ^J_H hhH*OJQJ^J_H hhH*OJQJ^J_H hH*OJQJ^J_H hyH*OJQJ^J_H hyhyH*OJQJ^J_H hyhyH*OJQJ^J_H hyOJQJ^J_H hOJQJ^J_H      "&'(STµ››}qahh H*OJQJ^J_H h OJQJ^J_H h h OJQJ^J_H hhOJQJ^J_H h H*OJQJ^J_H hH*OJQJ^J_H hyH*OJQJ^J_H hhH*OJQJ^J_H hhH*OJQJ^J_H hOJQJ^J_H " jhhOJQJ^J_H (  O67L 7$8$H$gdY 7$8$H$gd7 7$8$H$]gd  7$8$H$]gd7$8$H$]^gdY   ҴxlҴ\Oxh H*OJQJ^J_H hyh H*OJQJ^J_H hOJQJ^J_H h h OJQJ^J_H hH*OJQJ^J_H hyh H*OJQJ^J_H hh H*OJQJ^J_H h OJQJ^J_H " jh h OJQJ^J_H h H*OJQJ^J_H hh H*OJQJ^J_H hh H*OJQJ^J_H Ʒƌzk\L@\h7OJQJ^J_H h7h7H*OJQJ^J_H h7h7OJQJ^J_H h75OJQJ\^J_H " jhhOJQJ^J_H hhOJQJ^J_H hhH*OJQJ^J_H hOJQJ^J_H h h OJQJ^J_H hH*OJQJ^J_H h OJQJ^J_H hh H*OJQJ^J_H hh H*OJQJ^J_H Kghijklt$)567LƷh5OJQJ\^J_H hYH*OJQJ^J_H hYhYH*OJQJ^J_H hYOJQJ^J_H hY5OJQJ\^J_H h7hYOJQJ^J_H h7h7H*OJQJ^J_H h7h7OJQJ^J_H h7OJQJ^J_H /'1;EOY $$Ifa$gdJTn$$7$8$H$Ifa$gdJTn 7$8$H$gd #'.17;AEKOUYZ{|}̶uffWWWhJTnh-XOJQJ^J_H hJTnhl<OJQJ^J_H hJTnh=3OJQJ^J"hJTnh=35OJQJ\^J_H  hJTnh=3hJTnh=3OJQJ^J_H h7OJQJ^J_H *hJTnh=35CJ OJQJ\^J_H aJ *hJTnhJTn5CJ OJQJ\^J_H aJ hhOJQJ^J_H hJTn5OJQJ\^J_H "YZ"kd$$Ifl֞$ !&  t0644 laytJTnZ| $$Ifa$gdJTn$$7$8$H$Ifa$gdJTn  89BCLMVW`ajktvwɼɼ*hJTnhJTn5CJ OJQJ\^J_H aJ hJTnhl<OJQJ^J_H hJTnh=3OJQJ^J"hJTnh=35OJQJ\^J_H hJTnh=3OJQJ^J_H hJTnh-XOJQJ^J_H  hJTnh=38"kd$$Ifl֞$ !&  t0644 laytJTn $$Ifa$gdJTn$$7$8$H$Ifa$gdJTn"kd$$Ifl֞$ !&  t0644 laytJTn  $$Ifa$gdJTn$$7$8$H$Ifa$gdJTn9" $$Ifa$gdJTnkd$$Ifl֞$ !&  t0644 laytJTn9CMWaku $$Ifa$gdJTnuvw" $7$8$H$a$gdJTnkd4$$Ifl֞$ !&  t0644 laytJTnw $$Ifa$gdJTn$$7$8$H$Ifa$gdJTn  459:>?CDHIOPTVefjkoptuyz~ɼ۵۵۵۵۵۵ɼ۵۵۵۵۵۵ɼ۵۵۵۵۵۵ɵ۵۵۵۵۵۵hJTn5OJQJ\^J_H  hJTnh-XhJTnh-XOJQJ^J"hJTnh-X5OJQJ\^J_H hJTnh-XOJQJ^J_H *hJTnh-X5CJ OJQJ\^J_H aJ ;"kd$$Ifl֞$ !&  t0644 laytJTn  $$Ifa$gdJTn$$7$8$H$Ifa$gdJTn"kdN$$Ifl֞$ !&  t0644 laytJTn5:?DIPU $$Ifa$gdJTn$$7$8$H$Ifa$gdJTnUV"kd$$Ifl֞$ !&  t0644 laytJTnVfkpuz $$Ifa$gdJTn$$7$8$H$Ifa$gdJTn" $$Ifa$gdJTnkdh$$Ifl֞$ !&  t0644 laytJTn $$Ifa$gdJTn" 7$8$H$gd=3kd$$Ifl֞$ !&  t0644 laytJTn!!{#|#########$$7$8$H$Ifa$gd(6: 7$8$H$gdY]8 7$8$H$gd== 7$8$H$gd/^ 7$8$H$gd$w 7$8$H$gd=3Z[ !ef ( = !!@!e!!!!!!!"вв|p`hh>*OJQJ^J_H h7OJQJ^J_H hpOJQJ^J_H hY]8OJQJ^J_H hJTnh==OJQJ^J_H hJTnh/^OJQJ^J_H "hJTnh/^6OJQJ]^J_H h$wOJQJ^J_H "hJTnh=36OJQJ]^J_H hJTnh=3OJQJ^J_H h5OJQJ\^J_H !"">"#^#z#{#|###########$ $!$"$#$$$%$)$*$1$;$<$=$D$Y$Z$[$c$o$$$ǻuuih(6:OJQJ^J_H "hY]8h(6:5OJQJ\^J_H %hY]8hY]85H*OJQJ\^J_H "hY]8hY]85OJQJ\^J_H hY]85OJQJ\^J_H hY]8OJQJ^J_H h7OJQJ^J_H hJTnhOJQJ^J_H "hh6OJQJ]^J_H hOJQJ^J_H &##"kd$$Ifl֞ xdP<(#\( 4 t0644 layt(6:########$$7$8$H$Ifa$gd(6:##"kd$$Ifl֞ xdP<(#\( 4 t0644 layt(6:#*$+$,$-$.$/$0$$$7$8$H$Ifa$gd(6:0$1$"kd$$Ifl֞ xdP<(#\( 4 t0644 layt(6:1$<$=$>$?$@$A$B$C$$$7$8$H$Ifa$gd(6:C$D$"kdS$$Ifl֞ xdP<(#\( 4 t0644 layt(6:D$Z$[$\$]$^$_$`$a$$$7$8$H$Ifa$gd(6:a$b$c$" 7$8$H$gdY]8kd$$Ifl֞ xdP<(#\( 4 t0644 layt(6:c$z${$|$}$~$$$$$$$%%&%'%N%O%P%Q%R%_%%X&u& 7$8$H$gdfr 7$8$H$gd(6: h7$8$H$^hgd(6: & F7$8$H$gd(6: 7$8$H$gdY]8$$$$$$$$$$$$$$$$%%% %!%"%#%M%N%R%_%b%u&v&&&&&'&'8(9(񶦖vd"hY]8hfr5OJQJ\^J_H h7CJOJQJ^J_H aJhfrCJOJQJ^J_H aJhP7CJOJQJ^J_H aJhCJOJQJ^J_H aJh(6:CJOJQJ^J_H aJh(6:OJQJ^J_H h(6:5OJQJ\^J_H h(6:h(6:H*OJQJ^J_H h(6:h(6:OJQJ^J_H %u&v&&x''9( 7$8$H$gdfr21h:pJTn/ =!"#$% $$If!vh5 555555#v #v:Vl t65 5ytJTn$$If!vh5 555555#v #v:Vl t65 5ytJTn$$If!vh5 555555#v #v:Vl t65 5ytJTn$$If!vh5 555555#v #v:Vl t65 5ytJTn$$If!vh5 555555#v #v:Vl t65 5ytJTn$$If!vh5 555555#v #v:Vl t65 5ytJTn$$If!vh5 555555#v #v:Vl t65 5ytJTn$$If!vh5 555555#v #v:Vl t65 5ytJTn$$If!vh5 555555#v #v:Vl t65 5ytJTn$$If!vh5 555555#v #v:Vl t65 5ytJTn$$If!vh5 5555554#v #v#v4:Vl t65 554yt(6:$$If!vh5 5555554#v #v#v4:Vl t65 554yt(6:$$If!vh5 5555554#v #v#v4:Vl t65 554yt(6:$$If!vh5 5555554#v #v#v4:Vl t65 554yt(6:$$If!vh5 5555554#v #v#v4:Vl t65 554yt(6:@@@ NormalCJ_HaJmH sH tH DA@D Default Paragraph FontRi@R  Table Normal4 l4a (k@(No Listj@j =3 Table Grid7:V09 :;Fh ; d '(  O67L'1;EOYZ| 9CMWakuvw 5:?DIPUVfkpuz{|*+,-./01<=>?@ABCDZ[\]^_`abcz{|}~%&'NOPQR_Xuvx; 00000000000000000000000000000000000@00000 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 00 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 00000000000 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 00 0 0 0 0 0 0 0 00 0 0 0 0 0 0 0 000000000 000 000 00000000000000:;Fh ; d '(  O67L'1;EOYZ| 9CMWakuvw 5:?DIPUVfkpuz{|*+,-./01=>?@ABCD[\]^_`abcz{|}~'vx; 000000000000000000000000000000000000000000000000000000000 00000000 00000000 0 000000000000000000000000 00000000 00000000 0 00000000000000000000000000000000000000000000000000000000000000 0 00'0(<0'00'00000 "$9( #,78C(YZ9uwUV####0$1$C$D$a$c$u&9(!"$%&'()*+-./01234569:;<=>?@ABD9( L N W Y ` b #%yVcv| dj~   %.79<>ACFHMORThjmortwy|~ 'np$&; G L p t TD-`c_X]np; 3333333333333333333337LZ~89uw45ef`z{|1;DYcR_; { 0[L;^`o(. ^`hH. pLp^p`LhH. @ @ ^@ `hH. ^`hH. L^`LhH. ^`hH. ^`hH. PLP^P`LhH.{ 0[         ji/^  ==SDm't Zs"';/Fe1=3h05x6T(8Y]8(6:ZAEIF}G6QI K[O_OTQUWUQW-\ _`1_.a rce!#f-df+5g hYOh8Ti!Glm}'mJTnbpppfrGu v:xylGFwq "x:X-{7 3jW m6uMWr$/)e4l<7n$wXscA p&YmBlBlP-XP7QYD)0L'1;EOYZ| 9CMWakuvw 5:?DIPUVfkpuz*+,-./01=>?@ABCD[\]^_`ab; @x\(9 @UnknownG:Ax Times New Roman5Symbol3& :Cx Arial?Times-Roman;Wingdings=Times-BoldATimes-Italic"qhh&h&j:j:!24) )  2Q KX ?=32PIn this reaction, potassium iodate and sodium metabisulfite react to form iodine Ellen Berwick Ellen Berwick Oh+'0$0@ Xd   TIn this reaction, potassium iodate and sodium metabisulfite react to form iodineEllen BerwickNormalEllen Berwick2Microsoft Office Word@F#@PfK@PfKj՜.+,0D hp  %Hewlett-Packard:) ' QIn this reaction, potassium iodate and sodium metabisulfite react to form iodine Title  !"#$%&'()*+,-./0123456789:;<=>?@ABCDEGHIJKLMOPQRSTUVWXYZ[\]^_`abcdefghijklmnopqrsuvwxyz{}~Root Entry FKData F1TableNLJWordDocument4SummaryInformation(tDocumentSummaryInformation8|CompObjq  FMicrosoft Office Word Document MSWordDocWord.Document.89q