Unit 6: Equilibrium

Water Lab

Equipment needed:

2 50-ml graduated cylinders, one labeled "A" and the other "B"

2 beakers

Procedure:

The procedure for this lab involves the exchange of water between two graduated cylinders, A and B.

1. Record the volumes of water in each graduated cylinder.

2. Pour 1/2 of A into an empty beaker.

3. Pour 1/3 of B into the other empty beaker.

4. Exchange the beakers and pour the contents into the graduates.

5. Repeat from step 1 four more times.

6. After 5 exchanges, pour out the contents of A and repeat from step 1.

Group 1 Starting A 50 mL, Starting B 0 mL
Group 2 Starting A 40 mL, Starting B 10 mL
Group 3 Starting A 30 mL, Starting B 20 mL
Group 4 Starting A 25 mL, Starting B 25 mL
Group 5 Starting A 15 mL, Starting B 35 mL
Group 6 Starting A 0 mL, Starting B 50 mL

Write-up: tabulate and then graph your results. Related mathematical concepts: asymptotes and limits.

LeChatelier's Principle

Part I.

Take 1 mL of stock solution (12 g of CoCl2 dissolved in 20 mL of water and 80 mL of 6M HCl) in your test tube.

Add 0.5-1.0 mL of 6 M HCl to the test tube. Record your observations after each of 8 additionals.

Pour half of the solution into a second test tube. Set it aside.

Add 1 mL of H2O to the test tube. Record your observations after each of 3 additions.

Take the reserved test tube and add 1 mL of 0.1 M AgNO3. Mix. Record your observations.

Part II

In a small erlenmeyer flask, mix 2 mL of stock solution with 6 mL of 6M HCl. The solution should be violet. If it is not, adjust with HCl or H2O as needed.

Divide the solution into 3 test tubes. Leave 1 at room temperature. Place 1 in an ice water bath. Place 1 in a 80-90 deg C hot water bath. Record your observations.

Part III

Observe the color of CoCl2 dissolved in H2O, ethanol, and acetone. Record your observations.

Write-up:

• procedure

• observations

• conclusions: You should explain your observations based on the reaction as given in class (which should appear in the writeup). You should make sure to note whether the forward reaction is exothermic or endothermic.