Stress Lab (Academic)

This lab will go in your lab book. Follow the directions below to complete the lab.

Purpose (put into lab book)

The purpose of this lab is to observe the effect of stress on a system at equilibrium.

Background (put into lab book)

- The system at equilibrium you will be studying is: (copy this equation, leaving space above it to draw arrows)

Hypothesis (put in lab book)

Refer to the equation in the background for the reaction you are studying. Using your knowledge from stresses covered yesterday, predict the shift of the system at equilibrium if the following stresses are applied (forward or reverse).

1. Adding Cl^-1 (by adding HCl, a source of Cl^-1)
2. Adding H₂O
3. Removing Cl^-1(by adding AgNO₃ the silver ions will react with the chloride ions to effectively remove them)

Removing H₂O (by adding acetone, in a similar sense that chemists add acetone to remove the last traces of water from glassware)

Materials (put in lab book)

Read the procedure below and list all of the materials required to complete this lab. Do not forget to include chemicals and glassware.

Procedure (you do not need to write this in lab book)

1. Label three test tubes 1-3.
2. Using the graduated cylinder, measure out 5 mL of the 0.2 M cobalt chloride solution and pour it into test tube 1 and another 5 mL into test tube 2.
3. Under the fume hood, pour 7 mL of concentrated HCl into test tube 1. Swirl the test tube gently and record observations in your data table. BEFORE CONTINUING COMPLETE THE ENTIRE ROW OF THE DATA TABLE FOR THIS STEP.
4. Pour approximately half of the contents of test tube 1 into test tube 3.
5. Add 7 mL of water to test tube 1. Swirl the test tube and record observations in the data table. BEFORE CONTINUING COMPLETE THE ENTIRE ROW OF THE DATA TABLE FOR THIS STEP.
6. Add 8 mL of 0.10 M silver nitrate to test tube 3. Swirl the test tube gently, and record the results in the data table. BEFORE CONTINUING COMPLETE THE ENTIRE ROW OF THE DATA TABLE FOR THIS STEP.

Measure 10 mL of acetone. Tilt test tube 2 and gently pour the acetone very slowly down the side of the test tube to avoid mixing the acetone and the cobalt solution. It should take you about 2 minutes! This step will not work unless the acetone remains a separate layer. Record results in the data table. BEFORE CONTINUING COMPLETE THE ENTIRE ROW OF THE DATA TABLE FOR THIS STEP.

Data (put into lab book)

Click here if you're absent to see pictures from lab.

Click here to see how you should copy this in your lab notebook!

Conclusion (answer in your lab book)

1. Make a chart showing what you predicted in your hypothesis and what you observed in your data table (as shown below). Do your predictions and observations match?

1. Predict the direction shift and the resulting color of the solution if CoCl4^-2 is added. (Copy the equation and show the arrows when answering this question.)
2. Predict the direction shift and the resulting color of the solution if Co(OH2)6⁺² is added. (Copy the equation and show the arrows when answering this question.)
3. Given the following system at equilibrium:

- 1. The reactants are a light blue color and the product is a deep blue color. Identify what chemical could be added to change a light blue solution deep blue? (You can just give me the formula)

Page updated

Google Sites

Report abuse