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Study guide for exam 2 - Friday, October 29, 1999

TOPICS

Chapter 5

  1. Know what valence electrons are and be able to determine the number of valence electrons for main group elements

  2. be able to draw dot structures for the representative elements

  3. be able to distinguish between an ionic compound and molecule

  4. know what types of elements combine to form ionic compounds and what kinds of elements combine to form molecules

  5. know the difference between cations and anions and why these ions form from atoms

  6. know how to name ionic compounds and know the names of the ions in the notes to lecture number 11.

  7. know how to correctly form ionic compounds from cations and anions (i.e. know how to write the formula for an ionic compounds formed between an anion and cation)

  8. know what a covalent bond is and what it means to form a single, double and triple covalent bond.

  9. Be able to use electron dot structure to determine the type of covalent bonding between atoms in molecules

  10. understand what factors contribute to determining the shapes of molecules.  be able to explain why ammonia, methane, and water have the structures that they do.  Understand the role that lone pair electrons play in this shape

  11. Understand the relationships between polar covalent bonds, polar molecules and electronegativity

  12. know periodic trends in electronegativity

 

Chapter 6 (you may omit sec. 6.4 on oxidation and reduction reactions)

  1. Understand what a mole is and what is the value of Avogadro’s number

  2. know what molar mass is and be able to calculate the molar mass, atomic mass and formula mass of a substance given in the periodic table

  3. Given a mass and formula of a substance, be able to determine the number of moles of that substance.

  4. Be able to determine how many grams you have of a substance given the number of moles of that substance

  5. understand what a chemical equation is and what it means to be balanced

  6. be able to balance some simple chemical equations

  7. be able to interpret balanced chemical equations in terms of particles, moles or mass

  8. be able to perform stoichiometric calculations such as mole-mole, mole-mass, and mass-mass.

  9. Know the difference between endothermic and exothermic reactions

  10. be able to explain how changes in energy and entropy affect the favorability of reactions.

  11. understand the concept of entropy and be able to identify whether the entropy increases or decreases for a particular process.

  12. Understand the concept of free energy and spontaneous chemical reactions

  13. understand the rate of a reaction and how this is affected by temperature, catalysts and concentration.

  14. understand what activation energy is

  15. understand what is meant by the terms “reversible reaction” and “chemical equilibrium”

  16. Understand LeChatelier’s principle

STUDYING

Again – you should work as many problems as possible to test your understanding:

 Here are some additional problems to study: 

 CH5: 5.19, 5.25, 5.31, 5.37, 5.42, 5.46, 5.49, 5.51, 5.52, 5.57, 5.61, 5.63, 5.65, 5.71

CH6: 6.29, 6.37, 6.39, 6.41, 6.42, 6.43, 6.47, 6.51, 6.53, 6.57, 6.61 6.63

 The self-tests at the end of the chapters are also good to study:

FORMAT

The examination will be of similar format to exam one although there MAY be slightly more emphasis on written questions.  At least 70% of the exam will be multiple choice with approximately 20 multiple choice questions planned. 

 The written portion will likely focus on two topics 

  1. Using a variety of concepts (dot structures, octet rule, rules for molecular shape, electronegativity, bond polarity) of the class to explain why, for instance, water is a polar, bent molecule.

  2. Balancing a chemical equation