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LARN 168 C42D4

Study for the summative assessment on chapter 20 test on Oxidation-Reduction Reactions that is to be given on your next school day that our class meets.  Today is day 168.  Study for your test which is scheduled for school day 169!  If your class does not meet on day 169, today’s home learning activities are listed under day 169 and on day 169 your home learning activities are those listed below.

Start the following in class:

1.  Go to http://www.phschool.com/webcodes10/index.cfm?wcprefix=cda&wcsuffix=1200&area=view and take an online formative test for chapter 20, Oxidation-Reduction Reactions.  Then click on the Score My Test button and study anything that you do not yet understand.

2.a.  Review and study your notes, and your journal reflections. Study your learning log, your Cornell Notes, and anything that was misunderstood on the Chapter 20 Study Guides, Chapter 20 Section Reviews, Chapter 20 Oxidation-Reduction Reactions [Formative] Test A, and other work sheets which you now have checked using green ink.  Look up anything that you still don’t understand in your text, glossary, vocabulary study sheets, class notes, or come to help class if you need help.

2.b.  Examine this chapter’s learning objectives, one by one. 

Are you able to demonstrate your understanding or mastery of each of this chapter’s learning objectives?  

  1. Describe at least four different ways of defining oxidation.
  2. Describe at least four different ways of defining reduction.
  3. Describe what makes a reducing agent a reducing agent.
  4. Describe what makes an oxidizing agent an oxidizing agent.
  5. Correctly assign oxidation numbers to the atoms in uncombined elements, ionic species, and in covalent and ionic compounds.
  6. Correctly classify a given reaction as either being or not being an oxidation-reduction reaction.
  7. Correctly identify the reduction half reaction, oxidation half reaction, the initial state oxidizing agent, the initial state reducing agent for an oxidation-reduction reaction.
  8. Use oxidation numbers that you correctly assign to each atom shown in a chemical expression to aid in balancing that chemical expression that expresses a chemical reaction that occurs in either neutral, acidic, or basic media, and show your work for the entire process including a check for the chemical expressions charge and mass balance.
  9. Show all the work involved in applying the single atom oxidation number method for balancing chemical expressions. Be able to
    1. Correctly copy the formula and phase of each reactant and product in the unbalanced chemical expression onto the paper and then draw a short line segment above each atom’s element symbol in each given formula.
    2. Use the rules for assigning oxidation numbers to assign and record the oxidation number for a single atom of each element present in each substance or species on the short line segment drawn above the atom’s elemental symbol in each reactant and product formula, .
    3. If the expression to be balanced represents an oxidation-reduction (redox) process, write a reduction half reaction for a single atom of each substance being reduced and, underneath it, write an oxidation half reaction for a single atom of each substance being oxidized.
    4. Multiply the half reactions by appropriate multipliers such that the total increase in oxidation number is equal to the total decrease in oxidation number, and then use the resulting ratio of the number of atoms that are reduced to the number of atoms that are oxidized simultaneously to select appropriate coefficients to balance those reduced and oxidized atoms in the chemical expression.
    5. Compute and record the total charge of all the initial state species and compute and record the total charge of all of the final state species, that is, do a charge balance (T check).
    6. In acidic solution, add the necessary number of H+(aq) ions to the side of the chemical expression that needs more positive charge to bring it into charge balance.
    7. In basic solution, add the necessary number of OH –(aq) ions to the side of the chemical expression that needs more negative charge to bring it into charge balance.
    8. Perform a mass balance (another T check) to check that the total number of each kind of atom is the same in the final state as in the initial state.
    9. Bring the hydrogen or oxygen atoms back into balance by adding H2O(l) to the side of the expression that needs more hydrogen or oxygen atoms to bring the expression into mass balance.

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.  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.
  3. What have you learned from the formative assessment of each learning objective?