Experimental Procedure

Part A:

1. Obtain a bag containing 30 pieces of construction paper (10 each of 3 different colors) and 2 dice.
2. Separate the construction paper into 3 piles by color. Assign 1 color as A, 1 as B and 1 as C.Indicate your designation in your data section. Set the B and C piles as discard piles for useduring the experiment. They should be out of the way.
3. Begin with 10 A pieces of paper on your desk. (You should have 10 A, 0 B, and 0 C as indicatedin the data section prior to moving on to the next step). See the image below.
4. For each time step, roll 1 die for an A in the experimental pile and 1 die for a B in the experimental pile (this assumes both piles have paper available to roll for—if the experimental pile does NOT have an A or B, then skip that molecule type in number 5).
5. For each time stamp you will roll for EVERY piece of paper. Therefore you will roll 10 times before recording your data in your results section. Pick up each piece of paper:a. If the paper is an A piece of paper you will be evaluating the k1 reaction. Roll 1 die to see if the reaction occurs.i. If you roll a 1, no reaction occurs. Put the A back in the experimental pile.
   ii. If you roll a 2-6, a reaction occurs. Put the A into the discard pile and add a B to theexperimental B pile.
   b. If the paper is an B piece of paper you will be evaluating the k2 reaction. Roll 1 die to see if

   the reaction occurs.

i. If you roll a 2-6, no reaction occurs. Put the B back in the experimental pile.
ii. If you roll a 1, a reaction occurs. Put the B into the discard pile and add a C to the

experimental pile.

6. Once you have rolled a die for ALL ten pieces of paper, tally your results and record them in the datasection (even if no change occurs).
7. Continue until all the pieces of paper are present at C. (0 A, 0 B, 10 C)
8. In the graphing lab, you learned to enter equations into Microsoft Excel. You will use that skill here.
9. In Microsoft Excel type the experimental results as shown in the data section (long columns ratherthan the condensed version present in the data table).
10. Your [A]0 = 10. Enter values to the side for k1 = 0.1 and k2 = 0.6.
11. Use these values and the time dependent concentration of A, B and C to calculate the concentrationof what A, B and C SHOULD have been.
12. Overlay the graphs of the calculated values with the experimental values.
13. Adjust the rate constants until your graph data fits fairly well with your experimental.
14. Tape graphs of Concentration vs. Time for your experimental and calculated data in the spaceprovided.

Part B

1. Begin with 10 A pieces of paper on your desk. (You should have 10 A, 0 B, and 0 C as indicated in the data section prior to moving on to the next step). See the image below.
2. For each time step, roll 1 dice for the experimental A pile and 1 for the experimental B pile (assuming both piles have paper available to roll for, if one type is unavailable, then skip the step for the missing molecule type in number 3).
3. For each time stamp you will roll for EVERY piece of paper. Therefore you will roll 10 times before recording your data in your results section. Pick up each piece of paper:

a. If the paper is an A piece of paper you will be evaluating the k1 reaction. Roll 1 die to see if the reaction occurs.

i. If you roll a 2-6, no reaction occurs. Put the A back in the experimental pile.
ii. If you roll a 1, a reaction occurs. Put the A into the discard pile and add a B to the

experimental pile.
b. If the paper is an B piece of paper you will be evaluating the k2 reaction. Roll 1 die to see if

the reaction occurs.
i. If you roll a 1, no reaction occurs. Put the B back in the experimental pile.

ii. If you roll a 2-6, a reaction occurs. Put the B into the discard pile and add a C to the experimental pile.

4. Once you have rolled a die for ALL ten pieces of paper, tally your results and record them in the data section (even if no change occurs).
5. Continue until all the pieces of paper are present at C. (0, 0, 10)
6. In Microsoft Excel type the experimental results as shown in the data section (long columns).
7. Calculate Ln[A] and 1/[A] in new columns.
8. Graph [A] vs Time, Ln[A] vs Time, and 1/[A] vs Time. Include a trendline and R2 value on eachgraph.
9. Tape the graphs in the space provided.
10. Determine which graph is most linear to determine whether the reaction was 0, 1st or 2nd order withrespect to A. Include your reasoning in the space provided.

Part C

1. For this section we will be considering the reaction A + B  C. We will vary the amount of each reactant and compare the rate of reaction to determine the order of reaction with respect to each reactant. You will work as a table to make sure you have enough dice to proceed.

1. Begin with 5 A pieces of paper, 5 B pieces of paper.
   1. Roll a dice for each potential reaction (5 reactions could happen, so roll 5 die).
   2. For every dice that is 1-3, remove 1 A and 1 B and add a C piece of paper. Each time you roll, adjust the number of die rolled to the number of A papers you have.
   3. For every 4-6, no reaction occurs.
   4. Record your data for each time stamp.
   5. Continue until no A and no B are left and all your paper is now in the C column.
2. Begin with 10 A pieces of paper, 5 B pieces of paper.
   1. Roll a dice for each potential reaction (5 reactions could happen, so roll 5 die).
   2. For every dice that is 1-3, remove 1 A and 1 B and add a C piece of paper. Eachtime you roll, adjust the number of die rolled to the number of B papers you havesince this is the number limiting the number of reactions that can happen. .
   3. For every 4-6, no reaction occurs.
   4. Record your data for each time stamp.
   5. Continue until no A or no B are left and no reactions are possible.
3. Begin with 5 A pieces of paper, 10 B pieces of paper.
   1. Roll a dice for each potential reaction (5 reactions could happen, so roll 5 die).
   2. For every dice that is 1-3, remove 1 A and 1 B and add a C piece of paper. Eachtime you roll, adjust the number of die rolled to the number of A papers you havesince this is the number limiting the number of reactions that can happen.
   3. For every 4-6, no reaction occurs.
   4. Record your data for each time stamp.
   5. Continue until no A or no B are left no further reactions are possible.

2. In the space provided compare the number of steps (time it took) for each reaction to complete.

Use this experimental data to determine the order of reaction with respect to A and B. If it is 0 order then doubling the concentration will have no effect on the rate of reaction. It if is 1st order, doubling the concentration will double the rate of reaction (happen in 1⁄2 the number of steps). If the reaction is 2nd order with respect to a reactant, doubling that concentration will quadruple the rate of reaction.

3. To find the experimental order of reaction: use 2x = magnitude of difference in steps or:

2𝑥 = # 𝑠𝑡𝑒𝑝𝑠 𝑟𝑒𝑎𝑐𝑡𝑖𝑜𝑛 2 𝑡𝑜𝑜𝑘 # 𝑠𝑡𝑒𝑝𝑠 𝑟𝑒𝑎𝑐𝑡𝑖𝑜𝑛 1 𝑡𝑜𝑜𝑘

Show your work. Make sure you round to a whole number (0, 1 or 2).

Pre-lab Assignment/Questions

1. N o t e – this pre-lab must be finished before you come to lab. (Please see syllabus for how to submit this assignment.)

What is the differential rate law expression for the change in concentration of A, B and C for the process: (you will have 3 equations).

𝑘1 𝑘2 𝑎𝐴→ 𝑏𝐵→ 𝑐𝐶

2.

Compare reaction 1 and 2 in Part A. Which reaction rate constant should be larger? Why? How much larger should it be? Be sure to explain your reasoning.

3.

Compare reaction 1 and 2 in Part B. Which reaction rate constant should be larger? Why? How much larger should it be? Be sure to explain your reasoning.

Experimental Data and Results

Part A

Attach a graph below of the experimental and calculated Concentration [A] vs.Time plots for Part A. Concentration vs. Time for [A].

Experimental Data and Results

Part A: Include the graph of the experimental and calculated Concentration [B] vs. Time.

Part A: Include the graph of the experimental and calculated Concentration [C] vs. Time for [C]

Experimental Data and Results

Part B

Attach a graph below of the Concentration [A] vs. Time.

Experimental Data and Results

Part B: Include the graph Ln [A] vs. Time.

Part B: Include the graph Concentration-1 (1/[A]) vs. Time.

Experimental Data and Results

Part C

Use your experimental data to fill in the table below:

Post Lab Questions

*See this syllabus for instructions on how to turn in this section of the lab handout.
1. What order of reaction is of AB with respect to A according to the graphs you made in Part

B? Justify your answer.

2. Based on your findings, what order of reaction is A+B → C with respect to A? With respect to B?

3. Use the table you made in Part C to write the rate law for A + B  C.