Chem 121
Exam 2 Study Guide
For this exam, you may have notes and equations written on ONE side of a 4 x 6 index card. You will be turning your notecard in with your exam.
You will need a calculator.
Lab 3 and the end of Chapter 4:
 Shapes of Molecules: o Be able to draw an electron dot structure for a molecule and use VSEPR theory to determine the shape of a molecule for a molecule that has 2-4 electron groups (i.e. linear, trigonal planar, bent, tetrahedral, trigonal pyramidal). You do not need to memorize names of things with 5+ electron groups.
Chapter 5: Chemical Reactions and Quantities
 Be able to identify physical versus chemical changes
 Be able to balance a chemical equation and understand/apply the law of conservation of matter
 Be able to identify combination, decomposition and replacement reactions
 Know what makes a reaction Redox , be able to identify what ion/element is oxidized and what ion/element is reduced , and be able to write the oxidation and reduction equations
 Know how to convert between moles, grams and atoms, and be conversant with the molar mass of both elements and compounds
 Be able to use mol-mol factors (aka stoichiometry ) to determine how much of a product will be formed from a given amount of reactant (or how much reactant is needed to generate a given amount of product)
 Be able to calculate a % yield
 Be able to determine what the limiting reactant in a reaction will be
Chapter 6: Energy and Matter
 Know the difference between potential and kinetic energy
 Know the difference between endothermic and exothermic reactions and understand the relationship between those and 
H rxn
 Understand activation energy
 Understand and be able to identify the parts of an energy vs. progress of reaction plot (like those on page 223)
 Know the definition of specific heat and how to calculate it, and how to use it to determine the heat needed or released during a temperature change
 Know how a calorimeter is used to determine the amount of calories in food
 Know the different kinds of attractive intermolecular forces, and their strengths, and how these relate to different states of matter.

 Know the names for the different changes of state, and know during which phase changes heat is absorbed and during which heat is released
 Be able to use  H fusion and  H vaporization
to calculate the heat released or absorbed during a phase change
 Understand the different parts of a heating/cooling curve
Chapter 8: Solutions
 Know basic solution terminology: solute, solvent, solution, concentration, saturated, unsaturated, hydration, etc.
 Be able to use the “like dissolves like” role to determine whether or not a solute will dissolve in a given solvent
 Know the difference between how an electrolyte vs. a nonlectrolyte dissolves and know how to determine equivalents (and use equivalents to determine what solution will be the strongest electrolyte)
 Given the table from page 301, be able to determine which ionic salts will be soluble in water and predict what the precipitate will be in a given solution (as on page 302)
 Be conversant with the following ways of calculating concentration: mass percent, volume percent, mass volume percent, and Molarity
 Be able to use the c
1 v
1
= c
2 v
2
formula to calculate concentrations or volumes when solutions are dilluted
Labs 4-6 will not be explicitly covered on the exam. However, a basic familiarity with the concepts presented in these labs is expected (i.e. you should have an understanding of how you calculated the molar mass of CO
2
, identifying different types of reactions, solution stoichiometry). You do not need to know anything about the ideal gas law for this exam.
The following information will be provided if you need it:
*the periodic table from the inside cover of your book
*1 cal = 4.184 Joules
*Specific heat of any compound (including water)
* 
H of reaction, fusion or vaporization for any problem concerning those
*Table 8.3 (solubility of salts in water)
Anything else is fair game (i.e. will not be provided ), including:
*Avogadro’s Number
*Converting between Celsius and Kelvin
*Converting between different kinds of metric units