Kinetics LabA little help to get you started

PreLab Q1

Hint: The reaction time is NOT the rate. Time = secRate = mol/L sec

To find the rate of each of the three reactions, divide the molarity, 0.002M by the time for each reaction

PreLab Q1bUse the Differentiated Rate

equations to determine the orders of each reactant.

#1 rate = k[.04]x[.04]y #2 rate = k[.08]x[.04]y solving for x; x = 1PreLab Q1c: solve for y using #1 and #3

PreLab Q2Solve the same as Q1, except the

rate is given. Once you have determined the

overall rate equation, substitute any trial into the equation and solve for k

Use dimensional analysis to determine the units for k

PreLab Q3Save one entire page in your

composition book for this. We will cover the concept of temperature dependence on Monday.

Part 3 of the lab allows us to prove this assumption in the lab

PostLab Part 1Using your data from part 1,

calculate the average mass of one drop of water

Then…Mass 1 drop 1.00ml 1L = 1.00g 1000ml

This will give you the vol of 1 drop of water

PostLab Part 2Determine the mol S2O3

2-

In the lab, you used 1 drop of S2O3

2-

So…1 drop Q1 L .001mol = 1 drop 1 L

= mol S2O32-

Molarity

PostLab Part 2Determine the mol of BrO3

-

This is done by linking S2O32- to BrO3

- by using equations #1 and #3 on the front page of the lab. Because neither equation has both species, we will link the two using I2.

mole S2O32- 1 mol I2 1mol BrO3

- =

2mol S2O32- 3 mol I2

= mol S2O32-

Answer from last slide

PostLab Part 2Calculate the [BrO3

-]

mol BrO3- 1 drop =

12 drops L

= M BrO3-

Answer from last slide

Answer from Part 1

Total volume after mixing

PartLab Part2Calculate the Reaction Rates

M BrO3- =

Avg time (sec)

Perform this calculation for each of the seven trial. (Data Table page 79)

Answer from last slide

Average time for each trial in part 2

PostLab 2B…finallyNow you must calculate the molarity of

each species in the rxn: [I-] [BrO3-] [H+]

Use your dilution equation: M1V1= M2V2

[I-] .01M (2drops) = M (12 drops) = .00167M

[BrO3-] .04M (2drops) = M (12 drops) = .0067M

[H+] .10M(2 drops) = M (12 drops) = .0167M

This example is for trial #1. You must complete a similar set of calculations for each of the seven trials

PostLab 2COnce you have all your concentrations

and rates calculated, now you can solve for the orders of each of the three reactants, just like you did in PreLab Q1

Rate = k[I-]x [BrO3-]y [H+]z

Email me with questions or stop in Monday before school