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LARN 163 C41D3

Your Goals:

Reading section 20.1 should give you an idea of what happens during an oxidation process and what happens during a reduction process.  The journal questions bring out the meanings discussed in the reading selection.  The time focused on the reading and journaling is expected to be around 30 minutes.  The main concern for home learning activities is to develop understandings in your mind that you can then apply to solve problems.   Responding to the journal questions serves as a first step toward accomplishing that purpose.

A central focus of LARN 163 # 2 is to learn the four rules and six priorities for assigning oxidation numbers.  Try spending no more than 10 minutes studying the rules and follow up with applying those rules to the best of your ability in the time available on one or more of the problems listed.  Be patient and be ready to learn from your mistakes and struggles.

Start the following in class:

1.  Write your journal entry on sheets of three holed 8.5 inch by 11 inch ruled paper in your Journal notebook. In the upper right corner white space of each upward facing page, write your hand in number within a circle followed by your name. Each journal entry should either be at least a paragraph of exemplary writing and penmanship concerning a single topic, or be a concept map relating chemistry terms. Begin each day’s paragraph with a topic sentence, follow with explained instances, and close with a focused summary statement.  Rather than just to find answers to questions, the goal of journaling is to reflect on, synthesize, and clearly express your thoughts in statements of your own understanding, so do not paraphrase material from other sources that you do not understand.

The required learning journal activities, J163, for today are

  1. When an atom in a substance combines with one or more atoms of oxygen, what do we say has occurred to the atom?
  2. When an atom combined with oxygen in a compound separates from the oxygen, what do we say has occurred to the atom?
  3. When an atom in a substance loses one or more electrons to another atom or atoms and becomes a positive ion, what do we say has occurred to the atom?
  4. When an atom in a substance gains one or more electrons from another atom or atoms and becomes a negative ion, what do we say has occurred to the atom?
  5. When an atom in a substance reacts with one or more atoms and loses partial control of one or more pairs of bonding electrons to one or more electronegative atoms and becomes the positive end of one or more polar covalent bonds, what do we say has occurred to the atom?
  6. When an atom in a substance reacts with one or more atoms and, as the more electronegative atom, gains partial control over one or more pairs of bonding electrons and becomes the negative end of one or more polar covalent bonds, what do we say has occurred to the atom?
  7. Each atom of an element has at least two possible oxidation numbers, a zero, 0, if it is free, and something other than zero if it has combined.  How does one recognize whether an atom of an element is “free”, strictly elemental, uncombined?
  8. How does one recognize whether an atom of an element has “combined”?

2. Download the Oxidation and Reduction flipchart from your MNSD Google Drive > Student Resources > ActivInspire Flipcharts folder or from the Infinite Campus web site.  Read and study the How to Assign Oxidation Numbers document that is included among the first pages of your chapter 20 informational packet.  Before going on to the next item in today’s home learning activity, learn the the four rules and six priorities for assigning oxidation numbers to single atoms of elements by heart.

3.a.  Use the PQ5R or SQ5R method to prepare study guide for text section 20.1 on The Meaning of Oxidation and Reduction or go to https://socratic.org/chemistry  to research the topics brought up in section 20.1 of your text.  Read section 20.1 in your chemistry text, pages 630 through 638, 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 20 vocabulary list.

3.b.  After you have finished reading the assigned section of the chapter, answer the formative assessment questions and do some formative assessment problems to inform you about the degree of your comprehension and understanding.  Assessment questions are printed at the end of the section that you have just read.  Reflect on your answers to assure yourself that you have understood the major points in the section that you have just read.  Record your responses to questions that are challenging you, so that you can later review what you are learning.  If all problems seem easy to you, record the response to the problem that was least easy for you to answer.

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 C1.4 Responses where C1.4 represents Chapter1.section4.  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.

  • Study Conceptual Problem 20.1 on page 634 and then show your work including all oxidation number assignments for practice problems I20-1ab (In chapter 20, problems 1a and 1b) and I20-2ab.
  • Refer to the document entitled  How to Assign Oxidation Numbers and notice how the unknown oxidation number of an atom for which there is no standard assignment rule exists (such as the S atom in BaSO4) is determined by assigning the oxidation number to the other atom(s) for which there is a rule first, finding the subtotal(s) of charge for that/those atoms and writing it/them above the oxidation number(s) for that/those atom(s).  Then by using the idea that the total of all the subtotals of oxidation numbers will equal the total charge shown on the whole formula unit, the value of the unknown oxidation number for the atom can be determined by simple arithmetic.  Use the setup the document entitled  How to Assign Oxidation Numbers .  On p. 634, do
  • I20-1a 

   ___         ___              __  __           —- subtotal of charge

  ___         ___               __  __          —- oxidation number

2 Na(s)  +  S(s)  —–>   Na2S(s) .

  • I20-1b 

  ___         ___                     __  __         —- subtotal of charge

  ___         ___                     __  __        —- oxidation number

4 Al(s) + 3 O2(g) —–>    2 Al2O3(s)

  • In the Section Assessment 20.1 on page 638, read, analyze, describe and explain practice problems I20-3 (In chapter 20, problem 3), I20-4, I20-5, I20-6, I20-7a and b only, I20-8a and b only.  Use the setup similar to that shown above and identical to that given on the Introduction to Oxidation and Reduction flipchart to show your work.

After you have finished responding to the formative assessment questions and problems, check page R100 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.  Write down any question that you still have so that you can ask about it in class.  In the margin of your notebook page, circle the number of formative assessment questions do not have a suggested response given and check your response with that of your classmates when you come to class.

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

  1.  According to the textbook’s authors, the rusting process in moist conditions is a sequence of two oxidation-reduction chemical reactions (p.636).  During rusting elemental iron, Fe(s), corrodes in the presence of oxygen, O2(g), and water, H2O(l), in a sequence of two oxidation-reduction reactions.
    1. Leave two lines of empty space [for a title and for use in our next day’s learning journal] and on the third line write the first of two chemical equations that the text’s authors use to describe the process of elemental iron corroding in the presence of oxygen, O2(g), and water, H2O(l).
    2. Then skip four more lines, and on the seventh line write a chemical equation that describes the second step of the corrosion process that occurs in the presence of oxygen,O2(g), and water, H2O(l).  Write the chemical equation in such a way that the arrow between the initial and final states in this equation is positioned below the arrow in the first written equation.
    3. To obtain the net chemical equation for the rusting of iron, use the following instructions to add the two equations that the textbook authors give for the corrosion of iron in moist conditions and that you have written down.
  2. 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.  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.
  3. Review the SI prefixes and their meanings until you can readily explain the meaning of each listed SI prefix as a numerical multiplier.