Review Topics and Practice Evaluation Questions

These are the topics a student should know fairly well in order to skip Chemistry 122 and enter directly into Chemistry 123 or 128. The more difficult topics are marked with an asterisk. When examining each of these topics you should ask yourself: Could I quickly review this material and feel comfortable using it when needed? If the answers are mostly "yes," then you likely belong in Chemistry 123 or 128.

  • Measurements
    • Units
    • Significant figures
    • Use of exponents and logarithms
    • Temperature scales and interconversion
    • Density
    • Classification of matter (elements, compounds and mixtures)
  • Atomic Theory
    • Concepts of atoms, molecules, elements, and ions
    • Introductory concepts in atomic composition (protons, neutrons, electrons and isotopes)
  • Stoichiometry
    • Atomic and molecular weights
    • Moles
    • Percent composition of formulas *
    • Formulas of compounds
    • Balancing chemical equations
    • Calculation of amounts of reactants and products
    • Limiting reactant
    • Percent yield *
  • Gases
    • The measurement of pressure
    • The ideal gas law PV = nRT
    • Dalton's law of partial pressures *
  • Solutions
    • Composition of solutions (molarity, percent by weight or percent by volume*)
    • Net ionic equations and aqueous solutions

Here are two practice evaluation problems to give you an idea of some of the types of questions you will be asked on the self-administered evaluation. We expect you to use a chemistry textbook, a calculator, scrap paper, etc., to work on these.

  1. Flavor chemists think that the characteristic "green herbaceous vegetative" aroma of Cabernet Sauvignon wine arises from the chemical 2-methoxi-3-(2-methylpropyl)-pyrazine, with chemical formula C9H14ON2. In wine there are two molecules of C9H14ON2 for every 10 trillion (1013) molecules of water (H20, density = 1 g/mL). Assuming that wine is mostly water (i.e. 1.00 liter of wine can be considered 1.00 liter of water), estimate:

    a) The number of molecules of 2-methoxi-3-(2-methylpropyl)-pyrazine in 1.00 L of wine
    b) The mass of 2-methoxi-3-(2-methylpropyl)-pyrazine in 1.00 L of wine

    answers: a) 6.68 x 1012 molecules; b) 1.84 x 10-9 g

  2. An organic chemist anticipates synthesizing 75.0 mmol of banana oil (C7H14O2) and needs to know the following information:

    a) What is the mass of 75.0 mmol of banana oil?
    b) Given that its density is 0.876 g/mL, what is the volume of 75.0 mmol of banana oil?

    answers: a) 9.75 g; b) 11.13 mL