(a) Calculate the concentrations of the three species

KI,(NH_(4))_(2)S_(2)O_(8)

, and

Na_(2)S_(2)O_(3)

after mixing but before any reaction has occurred. (1 mark)\ Hint: your calculated

KI

should equal

0.016M

.\

M_(k1)=0.04M\ M=0.06M\ M=0.0007m

\

U_(N_(n_(2))S_(3))=0.01L\ M=0.0007m

\ Moles of

Kl=0.04\\\\times 0.02=0.0008

\ nolus of

(NH_(4))_(2)S_(3)O_(8)=0.06\\\\times 0.02=0.0012

\ Molzs of

\\\\Nu _(2)S_(2)O_(3)=0.0007\\\\times 0.01=0.000007

\ Concentration

=( moles )/( totalv ),

total

$=0.02(2)+0.01=0.06L

\ for

k1

\ (b) The basis of the "Method of Initial Rates" used in this experiment, is that the concentrations of reagents are essentially unchanged during the measurement time period. Calculate the

%

of the initial

(NH_(4))_(2)S_(2)O_(8)

that has reacted when the blue colour appears. (1 mark)

(a) Calculate the concentrations of the three species KI,(NH4)2S2O8, and Na2S2O3 after mixing but before any reaction has occurred. (1 mark) Hint: your calculated [KI] should equal 0.016M. Uk1=0.02LU(4H4S2O8=0.02LUNn2SSO3=0.01L=0.04MM=0.06MM=0.0007M Moles of Kl=0.040.02=0.0008 noles of (NH4)2S3O8=0.060.02=0.0012 MolzsofNu2S2O3=0.00070.01=0.000007 Concentration=totalVmolestotal$=0.02(2)+0.01=0.06L for k1 =0.0008=0.016Mfor(NH4)2S2O8forNn2S2O,=0.050.0008=0.016M=0.050.0012=0.024M=0.050.000007=0.00014m (b) The basis of the "Method of Initial Rates" used in this experiment, is that the concentrations of reagents are essentially unchanged during the measurement time period. Calculate the % of the initial (NH4)2S2O8 that has reacted when the blue colour appears. (1 mark)