Kinetics Scholarship Answers

 

1.       a)       H2O2 +       2H+   +       3I-     →      2H2O          +       I3-

 

          b)      H3O2+                   HOI            OH-             I2

 

          c)       I-       It is a reactant in the slow or rate determining step.

 

2.       As the reaction proceeds, reactants are converted into products and [CO] and [NO2] decrease causing the rate to gradually decrease.

 

3.       a)       H2      +       N2O2           →      N2O   +       H2O

 

          b)      The overall rate is slow, therefore there must be one slow step and step 1 and 2 are fast.

 

          c)       A chemical species produced in one step of a mechanism and then consumed in a later step.

 

4.       a)       CH3CHO    +       I2       →      HI     +       CH3I           +       CO

 

          b)      Rate determining

 

5.       a)

 

 

 


                                                                                     

                                                                                                Note that there are two activation energies one for each step

                                                                                                The second step is slow and has the higher Ea.

 

 

 

 

 

 

 

          b)      2NO           +       O2     →      2NO2

 

 

6.       a)       2NO2          →      NO3   +       NO

 

          b)      Slow, if the overall rate is slow, one step must be slow and step one is fast.

 

 

7.       a)       Keq   =       [NO2]2         =       (0.84)2         =       0.80

                                      [N2O2]                  (0.88)

 

 

          b)      The temperature was increased, When the temperature of an endothermic reaction is increased, it shifts to                the right.

 

 

          c)       [NO2] was increased, which caused the equilibrium to shift left and the [N2O2] to increase.

 

8.       a)       Blowing on the splint increases the [O2], which increases the reaction rate.

 

          b)      Method:      Water

 

                   Reason:      Water lowers the temperature resulting in less collisions and collisions with less energy.

 

                   Method:      Fire blanket, sand, stomping or CO2 Fire Extinguisher.

 

                   Reason:      Lowers [O2] and there are less collisions.

 

 

9.       Automobile catalytic converter. Pt, Pd, Rh & Ni catalysts convert CO to CO2 and NOx to N2.

 

          H2SO4 is used as a catalyst for many organic reactions. 

 

          Pt is used as a catalyst to convert H2 and O2 to H2O.

 

10.     a)      A collision is necessary in order to have a reaction as it supplies the energy required to break the chemical bonds.

 

          b)      low temperature, low [NOI], low surface area of I2(s), nature of the reactants.

 

11.     NO3   +       CO             →      NO2   +       CO2

 

          CO    +       N2O4           →      NO2   +       CO2   +       NO

 

          Mechanism 1, because [CO] is in the fast step and would not affect the rate.

 

12.     Open dish with candle on a digital balance.

 

          Allow the candle to burn while measuring the mass and time.

 

          Grams/minute      or      Grams/second

         

 

13.     There are more than three (6) reactant particles in the equation.

 

14.    

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 


15.     Disagree, only three reactant molecules would not require a mechanism.