Unit 2

There are three topics in Unit 2.  The first one, aqueous reactions and solution stoichiometry, takes a closer look at homogeneous mixtures (solutions), with a focus on solutions in water.  The way these solutions react in water is one focus, while quantitative calculations involving concentrations of solutions and stoichiometry in solution reactions is the other.

In the second topic, we will look at gases.  Our study of gases will include gas laws, which relate various properties of gases and describe the behavior of gases, and kinetic molecular theory, which provides a conceptual description on what gases look like at the atomic and molecular level and explains the predictions made by the gas laws.

The unit will end with the topic of thermochemistry, which is the study of the energy involved in chemical processes.  Our look at thermochemistry will include how energy is related to chemical reactions and various ways to calculate the energy involved in physical and chemical changes.

Unit 2 Learning Objectives

Aqueous Reactions and Solution Stoichiometry

  1. Write equations to show ion formation from electrolytes when they ionize or dissociate.
  2. Differentiate between the terms acid and base, strong acid and weak acid.
  3. Define and identify substances as strong, weak and non electrolytes.
  4. Identify the common strong acids and bases.
  5. Given the chemical formula of any atom, ion, or compound listed in the “”Formula and Nomenclature”” handout, give the name and vice versa.
  6. Calculate molarity, solution volume, or number of moles of solute, given any two of these quantities.
  7. Calculate the concentration of ions present for the solutions of strong electrolytes.
  8. Solve problems involving dilution of solutions.
  9. Use solubility rules to predict the water solubility of salts.
  10. Knowing the solubility rules, predict whether a precipitation reaction will occur.
  11. Write balanced molecular, complete ionic and/or net ionic equations.
  12. Define and identify end point, Stoichiometric point, standard solution and indicator.
  13. Calculate the mass of a substance produced or used in precipitation or  neutralization reaction.
  14. Identify a chemical reaction as dissociation, combination, decomposition, combustion, neutralization, single replacements, or double replacement.
  15. Given the reactants and the reaction type (dissociation, combination, decomposition, combustion or neutralization, single replacement, double replacement), predict the products and then balance the equation. (See the Chemical Reaction Handout.)

Gases

  1. Describe how a barometer can be used to measure gas pressure.
  2. Convert among various units of pressure, including torr, atmosphere, mm of Hg and Pascals.
  3. Solve problems relating to Boyle’s Law, Charles’ Law, the combined gas law, and Avogadro’s Law.
  4. Solve problems using to ideal gas law.
  5. Know the value of STP.
  6. Starting with the ideal gas law, derive a relationship that includes molar mass and gas density and then solve problems using it.
  7. Given temperature and pressure, convert between molar mass and gas density.
  8. Solve problems involving Dalton’s Law of Partial Pressures.
  9. Using a balanced chemical equation, convert from a given mass, moles or volume of one gas to mass, moles or volume of another.
  10. Calculate the mass of a reactant given the total volume, pressure and temperature of a gas collected over water.
  11. Describe the relationship between temperature, average velocity, and kinetic energy.
  12. List and explain the principle points of the kinetic molecular theory of gases and describe the major factors responsible for real gases deviating from ideal gas behavior.
  13. State Graham’s Law and use it to solve problems.
  14. Explain the origin of the correction terms to P and V which appear in Van der Waals equation.

Thermochemistry

  1. Define the terms energy, work, kinetic energy, potential energy, power, system, surroundings, state function, and enthalpy.
  2. State and apply the first law of thermodynamics.
  3. Relate changes in enthalpy to changes in internal energy.
  4. Given the change in enthalpy for a reaction, calculate the heat transferred for a given amount of reactant.
  5. Using the relationship: q = Sp Ht x m x ΔT, determine the values of one of the variables given the values of the others.
  6. Solve calorimetry problems using heat gain equals heat loss and q = Sp Ht x m x ΔT.
  7. Calculate DH for a process given ΔH values for processes that can be combined (Hess’ Law) to yield the process of interest.
  8. Calculate the change in enthalpy for a reaction given the standard free energy of formation of reactants and products.
  9. Write equations that represent the standard enthalpy of formation of a substance.
  10. List the major sources of energy on which humankind must depend and discuss the likely availability of these sources in the future.

Unit 2 Topics

Study these in order:

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