Semester 2 Exam Review Notes

Unit 7: Nuclear Chemistry

• Know how to write out specific element names using its mass number (e.g., Carbon-12).
• Know the charges of up and down quarks.
• Know the penetrative power of the three major types of radiation (alpha, beta, gamma).
• Understand how alpha decay works.
• Be able to solve half-life problems.

Unit 8: Electronic Structure

• Know the number of orbitals in sublevels (s, p, d, f) and principal energy levels (n=1, 2, 3, …).
• Know the number of electrons in sublevels and principal energy levels (maximum 2 electrons per orbital).
• Know how to write electron configurations (e.g., $1s^22s^22p^6$) and orbital notations of elements.

Unit 9: Chemical Bonding

• Understand the major characteristics of metallic, ionic, and covalent bonds:
  • Metallic: Electron delocalization, conductivity.
  • Ionic: Electrostatic attraction between ions, formation of crystal lattices.
  • Covalent: Sharing of electrons between atoms.
• Be able to classify a bond as ionic, polar covalent, or nonpolar covalent by using electronegativity differences.
• Be able to calculate the percent ionic character of a bond.
• Be able to use the NAS (Needs, Available, Shared) system to draw Lewis structures of covalent compounds.
• Be able to identify the molecular structure of a compound based on VSEPR theory:
  • Linear
  • Bent
  • Tetrahedral
  • Trigonal Planar
  • Trigonal Pyramidal

Unit 10: Thermochemistry

• What is the definition of work, energy, temperature, and heat?
• Know that energy is released in an exothermic reaction and energy is absorbed in an endothermic reaction.
• Know that energy is released when bonds form and energy is absorbed when bonds break.
• Know how to use the equation $E = m \cdot C_p \cdot \Delta T$:
  • E = Energy (heat) transferred
  • m = mass
  • $C_p$ = specific heat capacity
  • $\Delta T$ = change in temperature
• Know how to solve Hess’ Law problems (calculating enthalpy changes of reactions using known enthalpy changes of other reactions).

Unit 11: Solutions and Equilibrium

• How do you find molarity, moles, or liters, given two of the variables?
• Understand how to manipulate a chemical reaction to favor either the forward or reverse reaction, according to Le Chatelier’s principle.
• How do temperature and pressure affect chemical equation equilibrium?
• Can you identify if a reaction is exothermic or endothermic by looking at the effect of heating or cooling the reaction?
• How do you write equilibrium constant equations? Can you solve for an unknown variable?

Unit 12: Acids and Bases

• Know what hydroxide ($OH^-$) and hydronium ($H_3O^+$) ions are.
• Know how to dissociate ionic compounds (e.g., $MgCl_2$ becomes $Mg^{2+}$ and $2Cl^-$-).
• Be able to solve for pH, pOH, [H+], and [OH-] when given one of the values.
• Know how the pH scale works and how it goes up by 10x per pH level (logarithmic scale).
• Be able to identify the acid, base, conjugate acid, and conjugate base in a chemical reaction.
• Know what it means when pure water is neutral at pH 7.
• Know how the concentration of hydrogen and hydronium affects pH level.

Unit 13: Organic Chemistry

• What are the characteristics of alkanes, alkenes, and alkynes? What are the general chemical formulas?
  • Alkanes: Single bonds, general formula $C<em>nH</em>{2n+2}$
  • Alkenes: At least one double bond, general formula $C<em>nH</em>{2n}$
  • Alkynes: At least one triple bond, general formula $C<em>nH</em>{2n-2}$
• Know how to name organic chemical structures (IUPAC nomenclature).
• Know how to draw the structure from its structural formula.

Equations Provided:

• $Molarity = \frac{Moles}{Liters}$
• $1 Liter = 1000 mL$
• $K_c = \frac{[Products]}{[Reactants]}$
  • Coefficients become exponents in the equilibrium expression.
• $pH + pOH = 14$
• $[H^+][OH^-] = 1.0 \times 10^{-14}$
• $pH = -log[H^+]$
• $pOH = -log[OH^-]$
• $[H^+] = 10^{-pH}$
• $[OH^-] = 10^{-pOH}$