Read
Chapter 16.3, pp 510 - 513
Do
Problems 22, 23, pg 533
Tuesday, February 28, 2017
Monday, February 27, 2017
Homework due 2.28.17
Read
Chapter 16.2, pp 506 - 510
Do
Problems 13, 15, 16
Lab prep for Tuesday:
Please read instructions for this lab, as time is limited, and we won't have enough time if you don't prepare.
Chapter 16.2, pp 506 - 510
Do
Problems 13, 15, 16
Lab prep for Tuesday:
Please read instructions for this lab, as time is limited, and we won't have enough time if you don't prepare.
pH Lab
Test-tubes with a capacity of around 10 mL are ideal. The test-tubes should be as clean as possible. Test-tubes, dropping pipettes and measuring cylinders should be washed in tap water and then rinsed with deionised or distilled water.
Procedure
Students 1 and 2
Test-tubes with a capacity of around 10 mL are ideal. The test-tubes should be as clean as possible. Test-tubes, dropping pipettes and measuring cylinders should be washed in tap water and then rinsed with deionised or distilled water.
Procedure
Students 1 and 2
a Number the test-tubes 1–7.
b Half-fill test-tube 1 with the hydrochloric acid solution.
c Transfer 1 mL of the hydrochloric acid into the measuring cylinder. Add distilled or deionised water to the measuring cylinder, up to the 10 mL mark.
d Pour some of the resulting diluted solution from the measuring cylinder into test-tube 2, enough to come to a similar height as the solution in test-tube 1.
e Carefully, pour away all but 1 mL of the solution remaining in the measuring cylinder. Now add distilled or deionised water to the measuring cylinder up to the 10 mL mark. Pour the resulting solution into test-tube 3. Continue in this way until you have solutions in test-tubes 1 to 6. Put only distilled or deionised water into test-tube 7.
Students 3 and 4
f Repeat instructions a – e using the sodium hydroxide solution instead of hydrochloric acid. Number the test-tubes 8–13.
Both groups
g Put the two racks of test-tubes together so that the solutions are in order 1 to 13. The test-tubes now have solutions in them with pH 1 (test-tube 1) to pH 13 (test-tube 13).
h Add a drop of Universal indicator to each test-tube. Rock each test-tube from side to side to mix the contents. Add more Universal indicator solution to each test-tube if needed to allow the colours to be seen more clearly. Be sure to add the same number of drops of indicator to each test-tube.
i Compare the colors of the solutions with the pH indicator chart.
b Half-fill test-tube 1 with the hydrochloric acid solution.
c Transfer 1 mL of the hydrochloric acid into the measuring cylinder. Add distilled or deionised water to the measuring cylinder, up to the 10 mL mark.
d Pour some of the resulting diluted solution from the measuring cylinder into test-tube 2, enough to come to a similar height as the solution in test-tube 1.
e Carefully, pour away all but 1 mL of the solution remaining in the measuring cylinder. Now add distilled or deionised water to the measuring cylinder up to the 10 mL mark. Pour the resulting solution into test-tube 3. Continue in this way until you have solutions in test-tubes 1 to 6. Put only distilled or deionised water into test-tube 7.
Students 3 and 4
f Repeat instructions a – e using the sodium hydroxide solution instead of hydrochloric acid. Number the test-tubes 8–13.
Both groups
g Put the two racks of test-tubes together so that the solutions are in order 1 to 13. The test-tubes now have solutions in them with pH 1 (test-tube 1) to pH 13 (test-tube 13).
h Add a drop of Universal indicator to each test-tube. Rock each test-tube from side to side to mix the contents. Add more Universal indicator solution to each test-tube if needed to allow the colours to be seen more clearly. Be sure to add the same number of drops of indicator to each test-tube.
i Compare the colors of the solutions with the pH indicator chart.
Tuesday, February 21, 2017
Homework/Agenda for 2.22.17
Solutions (Chapter 15) test on Friday
Ice Cream making on Thursday
Bring (everybody)
Read
Chapter 16.1, pp 503 - 506
Do
Problems 7 b,d, 8 b,c, 9 b,d, 10 b,d
Ice Cream making on Thursday
Bring (everybody)
- 1 qt Ziplok bag
- 1 gal Ziplok bag
- spoons
Read
Chapter 16.1, pp 503 - 506
Do
Problems 7 b,d, 8 b,c, 9 b,d, 10 b,d
Friday, February 17, 2017
Homework due 2.21.17
Read
Chapter 15.10, pp 495 - 496
Do
Problems 50, 51, 59
Calculation of Freezing Point Depression
Chapter 15.10, pp 495 - 496
Do
Problems 50, 51, 59
Calculation of Freezing Point Depression
If the solution is treated as an ideal solution, the extent of freezing-point depression depends only on the solute concentration that can be estimated by a simple linear relationship with the cryoscopic constant ("Blagden's Law"):
- ΔTF = KF · b · i,
where:
- ΔTF, the freezing-point depression, is defined as TF (pure solvent) − TF (solution).
- KF, the cryoscopic constant, which is dependent on the properties of the solvent, not the solute. (Note: When conducting experiments, a higher KF value makes it easier to observe larger drops in the freezing point. For water, KF = 1.853 K·kg/mol.[7])
- b is the molality (moles solute per kilogram of solvent)
- i is the van 't Hoff factor (number of ion particles per individual molecule of solute, e.g. i = 2 for NaCl, 3 for BaCl2)
Thursday, February 16, 2017
Homework due 2.17.17
Homework
|
Read Chapter 15.8, 15.9, pp 488 - 495
Do Problems 39, 41b,d, 44b,c, 48, pg 501 |
Tuesday, February 14, 2017
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