Experimental Procedure

Part A:

1. Obtain a bag containing 40 pieces of construction paper (20 each of 2 different colors) and 5 dice.
2. Separate the construction paper into 2 piles by color. Assign one color as A and one as B. This will represent the reaction A ↔ B.
3. Set the B pieces of paper aside in the discard pile: We will begin with all A in our experimental pile (20 A, 0 B) as shown below. Notice the papers are organized in 4 rows with 5 pieces of paper each for easy tallying in your data section.
4. For each time stamp in the data section, you must roll for EVERY piece of paper. This means you will roll 20 times. For the first time stamp, you can ONLY roll for A since there are no B papers present. For each subsequent time stamp, roll for whichever paper you have. (You will roll for all 20 papers in the experimental pile EACH time). Pick up each piece of paper in order. Roll the dice to determine if it will react.

5. Roll for each piece of paper.
   1. If it is an A piece of paper:i. If you roll a 1-3, a reaction happens. Put each piece of A that reacts into the discard pile and replace it with a B in the experimental pile.ii. If you roll a 4-6, a reaction does not occur. Leave the A in the experimental pile.
   2. If it is a B piece of paper:i. If you roll a 1, a reaction happens. Put each piece of B that reacts into the discard pile and replace it with an A in the experimental pile.ii. If you roll a 2-6, a reaction does not occur. Leave the B in the experimental pile.
6. Once you have rolled for all 20 pieces of paper take a tally of what you have in your datasection. For example, your first time stamp may look like the image below. (This would be recorded as 15 A, 5 B in your data section). Then you can begin rolling again for a new time stamp using the rules above.

7. Continue rolling for 10 turns.
8. Graph the data in the space provided.

Part B:

1. Set up your workspace the same as in part A. We will begin with all A in our experimental pile (20 A, 0 B) as shown below. Notice the papers are organized in 4 rows of 5 pieces of paper each for easy tallying in your data section.

2. For each time stamp in the data section, you must roll for EVERY piece of paper. This means you will roll 20 times. For the first time stamp, you can ONLY roll for A since there are no B present. For each subsequent time stamp, roll for whichever paper you have. (You will roll for all 20 papers in the experimental pile each time).

3. Roll for each piece of paper.
   1. For each A piece of paper:
      i. if you roll a 1-3, a reaction happens. Put each piece of A that reacts into thediscard pile and replace it with a B in the experimental pile.
      ii. if you roll a 4-6, a reaction does not occur. Leave this A in the experimental pile.
   2. For each B piece of paper:
      i. if you roll a 1-3, a reaction happens. Put each piece of B that reacts into thediscard pile and replace it with an A in the experimental pile.
      ii. if you roll a 4-6, a reaction does not occur. Leave this B in the experimental pile..
4. Once you have rolled for all 20 pieces of paper take a tally of what you have in your datasection.
5. Continue rolling for 10 turns.
6. Graphthedatainthespaceprovided.

Part C:

1. Set up your workspace the same as in part A. We will begin with all A in our experimental pile (20 A, 0 B) as shown below. Notice the papers are organized in 4 rows of 5 pieces of paper each for easy tallying in your data section.
2. For each time stamp in the data section, you must roll for EVERY piece of paper. This means you will roll 20 times. For the first time stamp, you can ONLY roll for A since there are no B present. For each subsequent time stamp, roll for whichever paper you have. (You will roll for all 20 papers in the experimental pile each time).
3. Roll for each piece of paper.

a. For each A piece of paper:

c.

i. if you roll a 1, a reaction happens. Put each piece of A that reacts into the discard pile and replace it with a B in the experimental pile.

ii. if you roll a 2-6, a reaction does not occur. Leave this A in the experimental pile. For each B piece of paper:

i. if you roll a 1-5, a reaction happens. Put each piece of A that reacts into the discard pile and replace it with a B in the experimental pile.

ii. if you roll a 6, a reaction does not occur. Leave this B in the experimental pile.

4. Once you have rolled for all 20 pieces of paper take a tally of what you have in your data section.
5. Continue rolling for 10 turns.
6. Graphthedatainthespaceprovided.

Part D:

1. Set up your workspace as below. For this part of the experiment we will look at how equilibrium can be reached by beginning with all product. We will begin with all B in our experimental pile (0 A, 20 B) as shown below. Notice the papers are organized in 4 rows of 5 pieces of paper each for easy tallying in your data section.
2. For each time stamp in the data section, you must roll for EVERY piece of paper. This means you will roll 20 times. For the first time stamp, you can ONLY roll for B since there are no A present. For each subsequent time stamp, roll for whichever paper you have. (You will roll for all 20 papers in the experimental pile each time).
3. Roll for each piece of paper.

a. If it is an A piece of paper:

d.

i. if you roll a 1-3, a reaction happens. Put each piece of A that reacts into the discard pile and replace it with a B in the experimental pile.

ii. if you roll a 4-6, a reaction does not occur. Leave this A in the experimental pile. If it is a B piece of paper:

i. if you roll a 1-3, a reaction happens. Put each piece of A that reacts into the discard pile and replace it with a B in the experimental pile.

ii. if you roll a 4-6, a reaction does not occur. Leave this B in the experimental pile. 4. Once you have rolled for all 20 pieces of paper take a tally of what you have in your data

section.

4. Continue rolling for 10 turns.
5. Graphthedatainthespaceprovided.

Prelab 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.)

Write the equilibrium expression for the reversible reaction:

2 𝑁𝑎𝐶𝑙 + 𝐶𝑎𝐶𝑂3 ↔ 𝑁𝑎2𝐶𝑂3 + 𝐶𝑎𝐶𝑙2

Write the equilibrium expression for the following reversible reaction:

𝑁𝑎2𝐶𝑂3 + 𝐶𝑎𝐶𝑙2 ↔ 2 𝑁𝑎𝐶𝑙 + 𝐶𝑎𝐶𝑂3

How are the expressions in problem 1 and problem 2 related to one another?

2.

3.

4.

What can you expect the value of K to be for a reaction that is product favoured? What would the K value be if a reaction is reactant favoured?

Experimental Data and Results

Record the data for Parts A-D in the table below.

For each reaction, use probability to calculate the theoretical value of both Kf and Kr. Then use your

data at the time stamp 10 to calculate the experimental value of Kf and Kr.

Part A:

Theoretical Values (Probability)
Kf = Kr =

Experimental Values (Using Data)

Kf = Kr =
Do these values agree? If not explain what could have happened.

Show your work for each!

Keq =

Keq =

Experimental Data and Results Part B:
Theoretical Values (Probability)

Kf = Experimental Values (Using Data)

Kr =

Keq = Keq =

Kf =
Do these values agree? If not explain what could have happened.

Part C:

Theoretical Values (Probability)
Kf = Kr =

Experimental Values (Using Data)
Kf = Kr =

Do these values agree? If not explain what could have happened.

Kr =

Keq =

Keq =

CHM 112 Lab 7

Experimental Data and Results

Use your data to graph the progress (Number of A or Concentration of A vs. Time) for each reaction for all 10 time stamps.

Part A.

Did this reaction reach equilibrium? How do you know?

Part B.

Did this reaction reach equilibrium? How do you know?

CHM 112 Lab 7

Experimental Data and Results

Use your data to graph the progress (Number of A or Concentration of A vs. Time) for each reaction for all 10 time stamps.

Part C.

Did this reaction reach equilibrium? How do you know?

Part D.

Did this reaction reach equilibrium? How do you know?

Check this box if all materials in your tray have been cleaned, the trays and other materials have been returned to their proper position, and all items in your drawer are accounted for.

Instructor Signature_______________________________________________________________

Post Lab Questions

*See this syllabus for instructions on how to turn in this section of the lab handout.
1. Which reactions (Part A, Part B, Part C or Part D) were reactant-favoured? Which were product- favoured?

2. Were any of the reactions in Parts A-D neither reactant NOR product favoured? How do you know?

3. Use your graphs to explain what is meant by “dynamic equilibrium.”