Learning Objectives for Chemistry 118

 

When you finish your study of Chapter 1 you should be able to:

1. Convert numbers written in ordinary decimal notation to scientific notation and numbers in scientific notation to decimal notation.

2. Multiply, divide, add and subtract numbers written in scientific notation.

3. Use your calculator to carry out operations on numbers written in scientific notation. Refer to the manual that came with your calculator. Different models do this in different ways.

4. State the relationship of the uncertainty in a measurement to the number of significant figures in the measurement.

5. Determine the number of significant figures in any measured number.

6. Carry out addition, subtraction, multiplication and division operations on measured numbers and retain the proper number of significant figures in the answer.

7. State the base units for mass and length in the International System .

8. Explain how derived units are obtained from base units. State the derived units of area, volume, and density.

9. Write the names, symbols, and values for the SI prefixes found in table 1.2 .

10. State the SI values of the liter and angstrom which are common units encountered in chemistry.

11. State that 1 inch = 2.54 cm and 1 lb = 454 g. Other English-metric conversion factors can be looked up as needed.

12. Interconvert temperatures in the Fahrenheit, Celsius and Kelvin scales.

13. Write unit factors from statements of equality. For example the statement

12 in = 1 ft yields the unit factors 12 in/1 ft and 1 ft/12 in, both of which are equal to 1.

14. Use the unit factor method to carry out conversions from one set of units to another. It is very important that you become fluent with this method as it will be used for solving most numerical problems in the study of chemistry.

15. Be able to carry out calculations involving ratios of units such as density and concentration.

 

 

When you finish your study of chapter 2 you should be able to:

1. Discuss how the laws of conservation of mass, constant composition, and multiple proportions along with Dalton's atomic theory led to an understanding of chemical formulas by about 1860.

2. Describe in a general way the experiments which led to the discovery of the electron and the proposition of a nuclear model for the atom.

3. Define the term, isotope.

4. Given the symbol representing a particular isotope of an atom or ion, determine the number of electrons, protons and neutrons in that species.

5. Given the number of electrons, protons and neutrons in a chemical species write the symbol representing that particular isotope.

6. Describe what is meant by radioactivity and how the emission of alpha and beta particles can lead to the transmutation of elements.

7. Describe the general construction of the modern periodic table, thedifference between periods and groups (families). Distinguish among alkali metals, alkaline earth metals, halogens, noble gases, transition elements, metals, nonmetals, and metalloids.

8. Describe how molecules can be represented by molecular, structural,and condensed structural formulas.

9. Distinguish between molecules and ions. Indicate how ions are formed.

10. Distinguish between cations and anions. Given the charge on a cation or an anion, determine the total number of electrons present in that ion.

11. Be able to state the charge on simple cations and anions with a noble gas configuration.

12. State the names of simple monatomic cations and anions. Note that such anions have names that end in ide (e.g., oxide ion).

13. Memorize the names and formulas (including charge) of the polyatomic ions in tables 2.2 and 2.3.

14. Be able to state the names of binary molecular compounds or given the name of such a compound, state its formula. Learn the common names and formulas near the bottom of page 43.

15. State the names and formulas of simple binary and oxoacids.

When you finish your study of chapter 3 you should be able to:

1. Point out that the atomic mass scale used today is based on the assignment of a mass of exactly 12 amu for the isotope carbon-12.

2. Describe how the relative atomic masses (these are also called average atomic masses) of atoms found on the periodic table are determined by considering both isotopic masses and the relative abundance of the isotopes found in nature.

3. State the value of Avogadro's number to 4 significant figures and point out that it represents the number of atoms of carbon-12 in exactly 12 g of carbon-12, i.e., exactly 1 mole of carbon-12 or in general, the number of atoms of an element in a smaple whose mass in grams is numerically equal to the atomic mass of the element.

4. Use relative atomic masses, such as those found on a periodic table to calculate molecular masses and formula masses.

5. State that the mass in grams of one mole of atoms of any element, or molecules of any compound, or formula units of any salt is numerically equal to the relative atomic mass of the element, the relative molecular mass of the compound, or the relative formula mass of the salt.

6. Use the term molar mass to describe the mass in grams of Avagadro's number (onemole) of atoms, molecules or other entities.

7. Carry out mole-gram calculations such as those found on page 57. Note that the unit factor method previously employed for conversions is used in doing these kind ofproblems.

8. Given the formula of a compound, calculate its percentage composition.

9. Describe what is meant by the simplest or empirical formula of a substance and, given its molecular formula, write its empirical formula.

10. Given experimental data for the composition of a compound, determine its empirical formula.

11. Given the molar mass and empirical formula of a substance, determine its true molecular formula.

12. Given the products and reactants in a chemical system, write a balanced equation representing the reaction.

13. Carry out the type of stoichiometric calculations described on pages 64 and 65.

14. Define the term, limiting reactant, and given the amounts (masses or volumes) of reactants in a chemical reaction, determine which of those reactants is the limiting reactant.

15. Calculate the theoretical yield of a reaction based on complete consumption of the limiting reagent.

16. Calculate the percentage yield of a reaction based on its theoretical and actual yields.

 

When you finish your study of chapter 4 you should be able to:

1. Define what is meant by the molarity of a solution.

2. Be able to use the molarity of a solution to calculate the number of moles of solute in a given volume of solution and the volume of solution containing a given number of moles solute.

3. Write equations describing what happens when an ionic strong electrlyte dissolves in water. Given the molar concentration of such a solution, calculate the concentration of all ions present in the solution.

4. State in a general way what sorts of ionic compounds are most likely to be water soluble.

5. Use a precipitation diagram or solubility table to write net ionic equations for precipitation reactions. Describe what is meant by spectator ions.

6. Carry out limiting reactant problems involving net ionic equations.

7. Describe what is meant by the terms acid and base.

8. Describe the difference between strong and weak acids. Memorize the names and formulas of the strong acids in table 4.1. Describe the differnce between strong and weak bases. Memorize the names and formulas of the strong bases in table 4.1

9. Write net ionic equations for acid-base neutralization reactions.

10. Carry out calculations based on net ionic acid-base reactions (titrations) as shown on page 86.

11. Describe the terms oxidation and reduction in terms of electron loss and gain.

12. Describe what is meant by the terms oxidizing agent and reducing agent.

13. Calculate the average oxidation number of an element in a chemical substance.

14. Describe the processes of oxidation and reduction in terms of change in oxidation numbers.

15. Given a balanced redox equation carry out stoichiometric calculations for that system.

  

When you finish your study of chapter 7 you should be able to:

1. State the number of valence electrons for an atom or monatomic ion of any substance.

2. Describe how a Lewis structure gives information about shared and unshared (lone pair) electrons in a substance with covalent bonds. Note that covalent bonds normally occur between atoms of nonmetallic atoms.

3. Draw Lewis structures for species which obey the so-called octet rule.

4. State what is meant by the concept of resonance. Draw resonance strutures for such molecules as sulfur dioxide or ions as the carbonate ion.

5. Calculate the formal charge of any atom in a Lewis structure. Note that formal charge is the charge an atom would have if valence electrons in bonds were distributed evenly. Further note that oxidation number is the charge an atom would have if all bonds in a molecule were ionic.

6. Draw Lewis structures for molecules which do not obey the octet rule.

7. Distinguish between the electron-pair geometry and molecular geometry of chemical species. For example, the electron-pair geometry of water is tetrahedral while its molecular geometry is bent.

8. State the electron-pair geometry for any species with two, three or four "electron pairs" around a central atom. Note that the electrons in a double or triple bond are treated as if they are a single pair of electrons.

9. State the molecular geometry for any species with two, three or four electron pairs around a central atom.

10. Describe what is meant by the term, electronegativity and describe in a general way periodic variance in electronegativity. This information is found on page 154 of your text.

11. Describe the difference between polar and nonpolar bonds. For a polar bond, state which end of the bond is more negative and which end is more positive.

12. Describe what is meant by molecular polarity. Use the shape of a molecule to determine whether it is polar or nonpolar. Note that in a nonpolar molecule, the center of positive charge is in the same location as the center of negative charge.

When you finish your study of section 9.3 you should be able to:

1. State the properties of molecular substances.

2. Describe how boiling (and melting) points are related to the strength of intermolecular forces.

3. Describe what is meant by dispersion forces and indicate their relationship to molecular structure.

4. Describe how dipole forces operate between polar molecules.

5. Describe the conditions required for hydrogen bonding to occur.

6. Given the formula of a molecular substance, state which type of intermolecular forces should be the most important in determining the physical behavior of that substance.

 

When you finish your study of chapter 12 you should be able to:

1. Describe what is meant by the partial pressure of a gas.

2. Point out that for a system at equilibrium, the forward and reverse reactions are taking place at the same rate.

3. Write the equilibrium constant expression for a general system involving only gases.

4. Describe how the value of the equilibrium constant changes as the coefficients of the balnced equation change.

5. Describe how the equilibrium constant for a reaction that can be expressed as the sum of two or more reactions is the product of the equilibrium constants for the individual reactions.

6. Write the equilibrium constant expression for a heterogeneous reaction system.

7. Given initial and equilibrium partial pressure, calculate the value of the equilibrium onstant. This may involve the use of a table such as is found on page 330. This type of table is extremely useful. Be sure that you understand its construction.

8. Describe the difference between the equilibrium constant, K, and the reaction quotient, Q. Describe how the relative values of the two can tell you whether or not a system is in a state of equilibrium, and if it is not, what changes the system must undergo in order to establish a state of equilibrium.

9. Given the value of the equilibrium constant and initial partial pressures, calculate equilibrium partial pressures.

10. State Le Chatelier's principle and indicate the effect of adding or removing products or reactants, compressing or expanding the system, and changing the temperature on the position of equilibrium.

When you finish your study of chapter 13 you should be able to:

1. State the Bronsted-Lowry definitions of acids and bases, and given an acid-base reaction equation, pick out the acid, base, conjugate acid, and conjugate base.

2. Describe what is meant by an amphoteric species.

3. Write the equation for the self ionization of water and the ion product constant expression for water. Memorize its value at 25 degrees.

4. Define what is meant by pH and pOH. Describe the pH and pOH of acidic, basic, and neutral solutions.

5. Given either hydronium (hydrogen) ion concentration, hydroxide ion concentration, pH or pOH of an aqueous solution, calculate the other three values.

6. Given the concentration of a strong acid or base, calculate its hydrogen and hydroxide ion concentrations and its pH or pOH.

7. Recognize that weak acids are either molecules containing ionizable hydrogen atoms or certain cations. Acidic cations can be viewed as hydrogen ion donors if they are bonded to water molecules in an aqueous solution. Recognize that the conjugate bases of weak acids are weak bases.

8. Write the form of the acid equilibrium constant, Ka, for a weak acid.

9. Note that as acids get weaker, the value of their Ka decreases. Also note that as they get weaker, the value of Kb for their conjugate base increases; that is, their conjugate bases get stronger. This type of information is summarized in tables such as table 13.2.

10. Calculate the hydrogen ion concentration and pH, pOH, or hydroxide concentration of an aqueous weak monoprotic acid solution given the concentration of the acid.

11. Recognize that weak bases are either molecules capable of accepting hydrogen ions or certain anions (the conjugate bases of weak acids).

12. Write the form of the base equilibrium constant, Kb, for a weak base.

13. Calculate the hydroxide ion concentration and pH, pOH, or hydrogen ion concentration of an aqueous weak base solution given the concentration of the base.

14. State whether a particular cation should be a weak acid or a spectator. State whether a particular anion should be a weak base or a spectator. (Note that few anions may be amphoteric)

15. State whether an aqueous solution of a given salt should be acidic, basic, or neutral.

When you finish your study of chapter 14 you should be able to:

1. Define the properties of a buffer.

2. Calculate the hydrogen ion concentration in a buffer solution.

3. Choose a buffer system that would be appropriate to maintain a particular pH.

4. Describe how the buffer capacity of a particular buffer is related to its composition.

5. Describe how an acid-base indicator functions. Note that its color changes when the pH of a system in which it is present is approximately equal to the pKa of the indicator.

6. Describe the general features of acid-base titration curves.

 

When you finish your study of the kinetic theory of gases (section 5.6) and chapter 11 you should be able to:

1. State the general assumptions of the kinetic theory.

2. Describe in a nonmathematical way what happens to the speed and kinetic energies of molecules as their temperature changes.

3. Describe what is meant by the average, instantaneous, and initial rates of a chemical reaction and indicate how one might determine them given experimental data.

4. Relate the rate of formation for a particular product to the rates of formation of other products and the rates of consumption of reactants in a chemical reaction.

5. Describe how experimental data can lead to the writing of a rate law expression.

6. Describe how integrated rate law expressions give information about the

relationship of reactant concentrations and time.

7. Describe the relationship of the rate constant and the half-life for a first order reaction.

8. Describe how a reaction mechanism can be viewed as a series of elementary steps which add up to the overall chemical process under study.

9. Determine which species are intermediates in a reaction mechanism.

10. Determine which species are catalysts in a reaction mechanism.

11. Describe what is meant by the rate determining step of a mechanism and show how a particular mechanism may or may not be consistent with a particular experimentally determined rate law expression.

12. Describe what is meant by a chain reaction and differentiate among initiation, propagation and termination steps in the mechanism.

13. Describe the dependence of the rate constant on temperature and activation energy.

14. Describe what is meant by activation energy.

15. Describe what factors are included in the Arrhenius coefficient, A.

16. Describe what is meant by a transition state.

17. Determine the activation energy and the energy change for a reaction using a transition state diagram such as figure 11.8.

18. Draw a reaction pathway for a catalyzed reaction on a transition state diagram.

19. Distinguish between homogeneous and heterogeneous catalysts and give an example of each.

 

When you finish your study of chapters 8 and 17 you should be able to:

1. Describe what are meant by heat capacity, molar heat capacity andspecific heat capacity, and given information about the temperature change of a material or system calculate each.

2. Recognize that heat lost by a system is equal to heat gained by its surroundings and apply this concept to calorimetric calculations.

3. Describe what is meant by enthalpy and note that it is a state property.

4. Distinguish between endothermic and exothermic reactions in terms of the enthalpy changes of both system and surroundings.

5. Given the ethalpy change for a chemical process, calculate the enthalpy change for the reaction of any amount of reactant or the production of any amount of product that is part of that process. (See examples 8.4-8.7)

6. Combine two or more chemical equations to give a desired equation and combine the enthalpy changes for each of those reactions to obtain the desired enthalpy change--that is, apply

Hess's Law. (See example 8.7)

7. Describe what is meant by standard state and formation.

8. Use standard enthalpies of formation to calculate the enthalpy change for a desired chemical reaction.

9. Describe what is meant by bond enthalpies and use them to determine the enthalpy change for a desired chemical reaction.

10. State the first law of thermodynamics in terms of heat and work.

11. Determine the energy change of a system in terms of heat lost or gained by the system and work done on or by the system.

12. State the relationship of energy change and enthalpy change for a system.

13. Note that exothermic reactions are generally, but not always spontaneous, and that endothermic reactions may be spontaneous.

14. Describe what is meant by entropy and what its relationship to disorder is.

15. State the third law of thermodynamics and show how standard molar entropies can be used to determine the entropy change for a chemical reaction.

16. State the second law of thermodynamics and indicate the relationship of entropy change to spontaneity of chemical reactions.

17. Describe what is meant by Gibbs free energy and its relationship to the spontaneity of chemical reactions.

18. Given the entropy and enthalpy changes for a system calculate the free energy change and indicate whether the system should undergo a spontaneous change.

19. Use standard molar free energy values to calculate the free energy change for a chemical reaction.

20. Determine for both positive and negative values of entropy change and enthalpy change whether a chemical reaction should be spontaneous or nonspontaneous, indicate whether temperature changes should affect that spontaneity, and, if so, in what way. (see section 17.5)

22. Note the relationship of standard free energy change and the value of the equilibrium constant.