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LARN 130 C33D2

Start the following in class:

1.a. The required focus topic, J130A, for today is:

You have a job as a laboratory technician.  Describe what must be done to prepare 175.0 mL of a 0.250 M CuSO4 aqueous solution. You will need to use the copper (II ) sulfate pentahydrate, CuSO4•5H2O(s), found in the stockroom to prepare the solution. 

  1. Describe what size volumetric flask that you would use and explain the reason for your selection.
  2. Show the calculation of the number of moles of CuSO4•5H2O(s) that must be measured into the volumetric flask that you selected to use.  Label all units and show cancellation of units for this calculation.
  3. Show the calculation of the number of grams of CuSO4•5H2O(s) that must be measured into the volumetric flask that you selected to use.  Label all units and show cancellation of units for this calculation.
  4. Describe the steps needed to prepare the 0.250 M  CuSO4(aq) solution starting with the quantitative transfer of the calculated number of grams of CuSO4•5H2O(s) into the volumetric flask that you selected.
  5. Describe what you would do with any extra 0.250 M CuSO4(aq) that you have prepared.

1.b.  The second required learning journal topic, J130B, for today is:

Colligative properties are properties of solutions that depend only on the number of solvated particles dissolved in the solution.

a. List four colligative properties.

b. Describe what happens to the vapor pressure of a solution when a particle of solvent escapes into the gas phase.

c. Describe the different kinds of forces of attraction that can cause different types of particles to be solvated when they dissolve in solution.

d. Explain why the vapor pressure of the solvent is lowered when the solute particles become solvated.

e. Explain why the vapor pressure is expected to be lowered twice as much if there are twice as many particles dissolved in the solution.

f. A solution boils when the vapor pressure of the solvent is equal to the pressure of the gas above the solution whose pressure exerted on the liquid previously kept bubbles of solvent vapor from forming throughout the liquid.  With that fact in mind explain why decreasing the vapor pressure of a solvent by dissolving solute particles into it results in an elevated boiling point.

2.a.  Use the PQ5R or SQ5R method to prepare study guide for text section 16.3 on Colligative Properties of Solutions or go to https://socratic.org/chemistry  to research the topics brought up in section 16.3 of your text.  Read section 16.3 in your chemistry text, pages 487 through 490, and as you do, create a study guide using the SQ5R or PQ5R method explained in class and on the distributed handout packet.  You may record vocabulary entries in the body of your study guide, or you may check them off on the chapter 16 vocabulary list that was distributed as you think about the meanings of the terms and add any notations to the vocabulary list for clarifications sake.

2.b. Writing in blue or black ink, place your hand in number in a circle followed by your name in the upper right white space of a piece of three holed composition paper that hasn’t been written on.  Place the page reference for the problems to be considered to the left of the red marginal line on the first blue line.  Centered on the first blue line,write a descriptive title for the learning activity such as Section [chapter #.section#] Responses.  Before you write your response to each question or problem listed below, write its designation to the left of the red marginal line as listed below, followed by your response in ink to the right of the marginal line.

  • In the Section Assessment 16.3 on page 490, read, analyze, describe and explain practice problems I16-24abc (In chapter 16, problem 24abc), and I16-25, and then show your work including all conversion ratios for practice problems I16-26ab, I16-27abc; I16-28.

After you have written your best effort response for each assigned item, check page R96 of the text and check each of those problems that you can by writing in either a check mark (√) or a correction in green ink as we do in class.

Recommended for those who have time left in their 45 minute study period, but not required of all:

1.  Review those concepts that we have discussed in class that are in your study guides, that are in your text study guide at the end of the chapter, and that on the chapter vocabulary sheet provided to you that describes what is a substance, an element, a compound, a coarse mixture, a colloidal suspension, a solution; an atom; a formula unit, a molecule;a phase, an aqueous phase; a chemical change, a physical change; a chemical reaction, a reactant, a product, a word equation, and a formula unit equation;and how are these concepts different?  You need to be able to explain the meaning of each of these terms, and be able to differentiate the terms, be able to compare and contrast these related terms, and give examples that make clear the points that you are trying to explain.  Go over each of these concepts with your study partner.

2. Review the SI prefixes and their meanings until you can readily explain the meaning of each listed SI prefix as a numerical multiplier.