LARN 131 C33D3

LARN 131 C33D3

Start the following in class:

1.a.  Use the PQ5R or SQ5R method to prepare study guide for text section 16.4 on Calculations Involving Colligative Properties or go to https://socratic.org/chemistry  to research the topics brought up in section 16.4 of your text.   Read section 16.4 in your chemistry text, pages 491 through 498,    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.  .

1.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.

Use dimensional analysis and/or the algebraic  definition of molal concentration  c_m = n_solute /(m_solvent  in kg) to help set up the next two problems.   Be sure both to include the units of  each measured quantity and to cancel all units that are both in a  numerator and a denominator of multiplied ratios. Also show the correct  answer circled and expressed to the proper number of significant  figures.

• Study Sample Problem 16.6 on page 492 and then show your work including all conversion ratios for practice problems I16-29 (In chapter 16, problem 29) and I16-30.

To help set up the next two problems use the  understanding that a fraction = (the part) / (the whole), so therefore  the algebraic definition of mole fraction of component a = # moles of a  / (total number of moles of all components) or X_a = n_a / (n_a + n_b + …) and the algebraic definition of mole fraction of component b = # moles of b / (total number of moles of all components) or, X_b = n_b / (n_a + n_b + …).  Be  sure to express the mole fraction as a decimal without any units.  Also  make sure the correct answer is circled and expressed to the proper  number of significant figures.

• Study Sample Problem 16.7 on page 493 and then show your work including all conversion ratios for practice problems I16-31ab (In chapter 16, problem 31ab) and I16-32ab.  To analyze  the next four problems and to find the proper factors to use, recall that the  magnitudes of a freezing point depression [compared to phase transition  point of the pure solvent], T_f, and the magnitude of a boiling point elevation [compared to phase transition point of the pure solvent], Tb, are both directly proportional to the molal concentration of the dissolved particles, cm.  That is, ΔT_f =  – K_f  ·  c_m for the freezing point depression when preparing a solution, and ΔT_b = K_b · c_m for  the boiling point elevation when preparing a solution.  When the solute  is molecular, the molal concentration of the dissolved particles is  equal to the molal concentration of the dissolved solute, but when the  solute is ionic, the molal concentration of the dissolved particles is  equal to the total molal concentration of all the positive and  negative ions produced when the formula units of the ionic compound  dissolved.  Be sure both to include the units of each measured quantity  and to cancel all units that are both in a numerator and a denominator  of multiplied ratios.  Also make sure the correct answer is circled and  expressed to the proper number of significant figures.
• Study Sample Problem 16.8 on page 495 and then show your work including all conversion ratios for practice problems I16-33 (In chapter 16, problem 33) and I16-34.
• Study Sample Problem 16.9 on page 496 and then show your work including all conversion ratios for practice problems I16-35 (In chapter 16, problem 35) and I16-36.
• In the Section Assessment 16.4 on page 496, read, analyze, describe and explain practice problems I16-37ab (In chapter 16, problem 37ab), and I16-38, and then show your work including all conversion ratios for practice problems I16-39, I16-40ab; I16-41.

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.  Study the Key Concepts given on pages 33, 57, 95, 121, 148, 180, 206, 246, 280, 314, 346, 378, 406, 438, 464 and 498 of the text.

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