Objectives for Exam 3

Acids and Bases

· Distinguish Arrhenius, Bronsted-Lowry, and Lewis acids and bases.

· Identify substances as acting as Arrhenius, Bronsted-Lowry, and Lewis acids or bases in a chemical reaction.

· Write the formulas for conjugate acids and bases.

· Write an equation to show the dissociation of a weak acid.

· Write an equation to show how the conjugate base of a weak acid acts as a base in water.

· Write an equation to show how neutral nitrogen compounds act as bases in water.

· Explain how the strength of an acid (K_a value) effects the pH of the acid

· Use K_a for an weak acid to calculate K_b for its conjugate base

· Use K_b for an weak base to calculate K_b for its conjugate acid

· Use K_a (or pK_a) values to compare the relative strengths of acids of bases

· Given one of the following, calculate the other three: [H⁺], [OH^-], pH, and pOH

· Calculate [H⁺], [OH^-], pH, and pOH in a solution of a strong acid or base

· Calculate [H⁺], [OH^-], pH, and pOH in a solution of a weak acid or base

· Calculate the pH or pOH and percent dissociation of a weak acid or base

· Given pH for a weak acid (or base), calculate its K_a (or K_b)

· Compare the relative strength of acids based on their structure

· Calculate the pH and [ ] of species present in a polyprotic acid

· Compare the pH of salts and write equations to explain their acid/base properties

· Calculate the pH of the four types of salt solutions.

Buffers, Titrations, and Indicators

· Explain how to make a buffered solution

· Calculate the pH of a buffered solution prepared by the three methods discussed

· Calculate the pH of a buffered solution after the addition of a strong acid or base.

· Know when and how to use the Henderson-Hasselbach equation to calculate the pH of a buffer solution.

· Describe the procedure for making a buffer of a specified pH.

· Explain buffering capacity and how a buffer resists change in pH

· Calculate pH values and sketch a graph of the titration of a strong or weak acid with a strong base. and describe the major regions of the graph. Remember there are 4 regions in the titration.

· Calculate pH values and sketch a graph of the titration of a strong or weak base with a strong acid and describe the major regions of the graph. Remember there are 4 regions in the titration.

· Generate a titration graph for the titration of a polyprotic acid

· Choose the appropriate indicator for a given titration

Quantum Model

· Understand wave model of light and properties of waves

· Understand the photon model of light

· Understand the significance of Young’s double slit experiment

· Understand the significance of the photoelectric effect

· Using the equations lu = c and E = hu, calculate energy, wavelength, or frequency

· Understand de Broglie’s hypothesis and use l = h/p to calculate l , p, or v

· Differentiate between a continuous and a line (discontinous) spectra

· Know the major concepts of the Bohr model of the H atom

· Given the equation, E = - R_H (1/n²), calculate the allowed energy levels of the H atom, the energies associated with transitions between energy levels, and the frequency of light produced by given energy transitions

· Know the significance of the wave function, Y, and Y² for the Schrodinger (or wave) model of the H atom

· Compare the Bohr model of an orbit and the Schrodinger model of an orbital

· Be able to predict allowed values of the quantum numbers or knowing quantum numbers predict the type of orbital

· Apply the aufbau, principle, Hund’s rule, and Pauli exclusion principle to writing electron configurations and orbital diagrams for atoms or ions

· Define ionization energy and electron affinity

· Predict and explain periodic trends in atomic radius, ionization energy, and electron affinity in moving across a row or down a column

· Explain increase in successive ionization energies for an element

· Compare and explain the sizes of isoelectronic species