Labs for General Chemistry II

INTRODUCTORY MATERIAL

Periodic Table

Tables of Physical Data

LABORATORIES

Emission and Absorption
- Purpose
  
  To determine the identities of ions in two solutions of unknown composition by comparing the colors they produce in flame tests with colors produced by solutions of known composition...
- Goals
  
  To gain practice using a Bunsen burner...
- Introduction
  
  When many people hear the word radiation, their first thought is something radioactive. However, a scientist thinks about energy moving through space in a series of waves called electromagnetic (EM) radiation or radiant energy...
- Equipment
  
  1 Bunsen burner, 1 Nichrome wire loop, 1 30 mL beaker, 1 spot plate, 1 grease pencil, 1 deionized water squirt bottle, 1 MicroLab spectrophotometer
- Reagents
  
  15 mL 3 M HCl(aq), 5 drops each known salt solution (0.1 M), 5 drops each unknown salt solution (0.1 M), Sample vials of...
- Part A Lab Procedure
  
  Obtain a wire loop and a spot plate from the set-up area. Using a grease pencil, label the wells on the spot plate with the formulas of the solutions you will be testing...
- Part B Lab Procedure
  
  Make sure that the MicroLab interface is connected to the computer and that the power is turned on. When the power is on, a green light appears in the "o" of MicroLab on the left of the instrument...
- Worksheet
  
  You will use a hard copy of this worksheet to enter data as you work through the experiment. Print the worksheet and bring it with you to the lab.
Freezing Point Depression
- Purpose
  
  To predict and measure the freezing point depression caused by a solute in a solvent.
- Goals
  
  To learn to accurately measure a freezing point depression for a solution...
- Introduction
  
  A solution is a homogeneous mixture of two or more substances. For the common two-component solution, the substance present in the major proportion is called the solvent and that in the minor proportion is called the solute...
- Equipment
  
  1 crystallization dish, 1 100 mL graduated cylinder, 1 30 mL beaker, 1 digital thermometer, 1 tongs, 1 spatula, 1 hot plate
- Reagents
  
  ~9 g stearic acid, ~2 g lauric acid
- Lab Procedure
  
  Prepare a hot water bath in your crystallization dish by heating about 85 mL of tap water on your hot plate (~1/2 filled)...
- Worksheet
  
  You will use a hard copy of this worksheet to enter data as you work through the experiment in lab. Print the worksheet and bring it with you to the lab.
Measuring Enthalpy Changes
- Purpose
  
  To observe changes in enthalpy in chemical processes.
- Goals
  
  To identify exothermic and endothermic processes...
- Introduction
  
  Chemical processes occur spontaneously when they lower the free energy of the system. The free energy at constant temperature and pressure is the Gibbs free energy,...
- Equipment
  
  1 30 mL beaker, 1 100 mL beaker, 1 10 mL graduated cylinder, 1 digital thermometer, 4 small test tubes,...
- Reagents
  
  ~2 g CaCl₂(s, anhydrous), ~2 g NH₄NO₃(s), 1 mL 1 M NaOH(aq),...
- Lab Procedure
  
  Use a spoon-type spatula to dispense anhydrous solid CaCl₂ into a dry 30 mL beaker...
- Worksheet
  
  You will use a hard copy of this worksheet to enter data as you work through the experiment. Print the worksheet and bring it with you to the lab.
Determinations of an Equilibrium Constant
- Purpose
  
  To determine the equilibrium constant for the reaction...
- Goals
  
  To gain more practice using a pipet properly...
- Introduction
  
  A typical chemical equation has the following form:
  aA + bB → cC + dD.
  This form of the equation assumes that the reaction proceeds completely to products...
- Equipment
  
  1 MicroLab spectrophotometer, 1 MicroLab spectrophotometer instruction sheet, 6 vials, 3 serological pipets, 1 pipet bulb, 3 30 mL beakers for reagents, 6 13 × 100 mm test tubes for mixtures...
- Reagents
  
  ~10 mL 0.100 M Fe(NO₃)₃ in 0.2 M HNO₃, ~10 mL 5.00 × 10^-4M NaSCN in 0.2 M HNO₃, ~15 mL 0.002 M Fe(NO₃)₃ in 0.2 M HNO₃...
- Lab Procedure
  
  A spectrophotometer will be set up in your work area...
- Worksheet
  
  You will use a hard copy of this worksheet to enter data as you work through the experiment in lab. Print the worksheet and bring it with you to the lab.
Equilibrium and Le Châtelier's Principle
- Purpose
  
  To observe systems at equilibrium, and to determine what happens when stresses are applied to such systems.
- Goals
  
  To observe the effect on equilibrium of adding or removing products and reactants...
- Introduction
  
  Many chemical systems are considered to be reversible...
- Equipment
  
  2 30 mL beakers, 1 100 mL beaker, 1 ceramic spot plate, 2 glass stir rods, 1 hot plate, 1 250 mL beaker for waste collection, 1 deionized water squirt bottle
- Reagents
  
  ~3 mL 0.010 M Fe(NO₃)₃, ~1 mL 0.10 M Fe(NO₃)₃, ~1 mL 0.05 M NaSCN...
- Lab Procedure
  
  In five wells on a ceramic spot plate, place 2 drops of 0.05 M NaSCN (sodium thiocyanate), 2 drops of 0.01 M Fe(NO₃)₃ solution, and 3 drops of deionized water...
- Worksheet
  
  You will use a hard copy of this worksheet to enter data as you work through the experiment. Print the worksheet and bring it with you to the lab.
Mixtures of Acids and Bases
- Purpose
  
  To investigate the resulting pH's of different mixtures of acid and base solutions.
- Goals
  
  To calculate the pH of pure acid and base solutions...
- Introduction
  
  Brønsted acids are defined as proton donors. When placed in water, Brønsted acids (HA) donate a proton to water to produce the conjugate base of the acid (A^-) and a hydronium ion (H3O⁺) according to the following reaction...
- Equipment
  
  1 25 × 150 mm test tube, 1 400 mL beaker (to hold the test tube), 1 glass stir rod, 1 10 mL graduated cylinder, 1 100 mL beaker, 2 30 mL beakers, 1 MicroLab interface, 1 MicroLab pH measurement instruction sheet...
- Reagents
  
  ~60 mL 0.1 M NaOH, 10 mL 0.1 M HCl, 10 mL 0.1 M NH₄Cl, 10 mL 0.1 M NaC₂H₃O₂, ~15 mL pH 4.00 buffer, ~15 mL pH 7.00 buffer, ~15 mL pH 10.00 buffer
- Lab Procedure
  
  In this experiment, you will be using pH electrodes connected to the MicroLab interface...
- Worksheet
  
  You will use a hard copy of this worksheet to enter data as you work through the experiment in lab. Print the worksheet and bring it with you to the lab.
Buffers
- Purpose
  
  To prepare buffers and measure the pH of each, and to prepare a buffer at a specific pH.
- Goals
  
  To learn to prepare buffers by both the direct and indirect methods...
- Introduction
  
  In dilute aqueous solutions, weak acids are slightly dissociated...
- Equipment
  
  2 30 mL beakers, 2 100 mL volumetric flasks, 1 10.0 mL volumetric pipet, 1 pipet bulb, 1 50 mL graduated cylinder, 1 10 mL graduated cylinder, 1 50 mL beaker, 1 100 mL beaker, 1 glass stir rod, 1 MicroLab interface, 1 MicroLab pH measurement instruction sheet, 1 pH electrode in pH 7.00 buffer...
- Reagents
  
  ~10 mL 6.0 M acetic acid (HC₂H₃O₂), <10 g solid sodium acetate trihydrate (NaC₂H₃O₂ · 3 H₂O), ~25 mL 1.0 M NaOH, 3 g solid Na₂HPO₄ · 7 H₂O, TBD solid NaH₂PO₄ · H₂O or solid Na₃PO₄ · 12 H₂O...
- Lab Procedure
  
  In this experiment, you will be using pH electrodes connected to the MicroLab interface...
- Worksheet
  
  You will use a hard copy of this worksheet to enter data as you work through the experiment in lab. Print the worksheet and bring it with you to the lab.
Titration Curves
- Purpose
  
  To determine the equivalence points of two titrations from plots of pH versus mL of titrant added.
- Goals
  
  To gain experience performing acid-base titrations with a pH meter...
- Introduction
  
  A titration is an analytical procedure in which a reaction is run under carefully controlled conditions...
- Equipment
  
  1 MicroLab interface, 1 MicroLab pH measurement instruction sheet, 1 pH electrode in pH 7.00 buffer, 2 30 mL beakers, 2 50 mL beakers, 1 250 mL beaker, 1 100 mL graduated cylinder, 1 20.00 mL volumetric pipet, 1 pipet bulb, 1 magnetic stir plate, 1 magnetic stir bar, 1 25 mL buret, 1 ring stand...
- Reagents
  
  ~25 mL 0.20 M potassium hydrogen phthalate (KHP), ~30 mL 0.20 M sodium hydroxide (NaOH), 3 drops phenolphthalein solution, ~25 mL 0.10 M sodium carbonate (Na₂CO₃), ~30 mL 0.20 M hydrochloric acid (HCl), 3 drops methyl orange solution, ~15 mL pH 4.00 buffer...
- Lab Procedure
  
  In this experiment, you will be using pH electrodes connected to the MicroLab interface...
- Worksheet
  
  You will use a hard copy of this worksheet to enter data as you work through the experiment in lab. Print the worksheet and bring it with you to the lab.
Solubility Product Constants
- Purpose
  
  To measure the solubility product constant (K_sp) of copper (II) iodate, Cu(IO₃)₂.
- Goals
  
  To measure the molar solubility of a sparingly soluble salt in water...
- Introduction
  
  In previous introductory chemistry courses, you learned some basic solubility rules that are useful in determining if an ionic solid will dissolve in water...
- Equipment
  
  15 13 × 100 mm test tubes, 5 stoppers, 1 test tube rack, 1 spatula, 1 glass stir rod, 1 MicroLab spectrophotometer, 1 MicroLab spectrophotometer instruction sheet, 6 vials...
- Reagents
  
  ~0.25 g solid Cu(IO₃)₂, ~5 mL 5.0 × 10^-4 M Cu(NO₃)₂, ~10 mL 1.0 × 10^-3 M Cu(NO₃)₂, ~10 mL 5.0 × 10-3 M Cu(NO₃)₂, ~5 mL 1.0 × 10^-2 M Cu(NO₃)₂, ~5 mL 5.0 × 10^-3 M KIO₃...
- Lab Procedure
  
  A spectrophotometer will be set up in your work area. Make sure it is plugged in and allow it to warm up...
- Worksheet
  
  You will use a hard copy of this worksheet to enter data as you work through the experiment in lab. Print the worksheet and bring it with you to the lab.
Qualitative Analysis II
- Purpose
  
  To develop a separation scheme and confirmatory tests for Fe³⁺, Ba²⁺, and Ag⁺ cations, and to use it to identify the ions in a sample of unknown composition.
- Goals
  
  To explore solubilities and reactivities of different metal ions...
- Introduction
  
  Qualitative analysis is the process by which components of mixtures are separated and identified...
- Equipment
  
  6 small test tudes, 1 test tube rack, 1 test tube brush, 3 glass stirring rods...
- Reagents
  
  In dropper bottles: 0.10 M Fe(NO₃)₃, 0.10 M Ba(NO₃)₂, 0.10 M AgNO₃...
- Lab Procedure
  
  In a 4 × 6 plastic well plate, prepare a three by three grid of cation solutions and confirmatory reagents...
- Worksheet
  
  You will use a hard copy of this worksheet to enter data as you work through the experiment. Print the worksheet and bring it with you to the lab.
Electrochemical Cells
- Purpose
  
  To see how changes in concentration and pH affect the potential in an electrochemical cell, and confirm the Nernst equation.
- Goals
  
  To examine how standard reduction potentials are measured...
- Introduction
  
  A galvanic cell is an electrochemical cell in which the spontaneous electrochemical reaction proceeds, that is, ΔG for the reaction is negative...
- Equipment
  
  1 MicroLab interface, 1 voltmeter alligator clip leads, 1 400 mL beaker for rinsings, 1 100 mL beaker, 1 salt bridge assembly, 1 hand-held pH meter, 1 deionized water squirt bottle, 1 eye dropper
- Reagents
  
  100 mL 0.1 M Zn(NO₃)₂ (in covered plastic container), 100 mL 0.1 M Cu(NO₃)₂ (in covered plastic container), 100 mL 0.1 M AgNO₃ (in covered plastic container)...
- Lab Procedure
  
  Open the MicroLab program. Make sure the alligator clip leads are connected to the interface...
- Worksheet
  
  You will use a hard copy of this worksheet to enter data as you work through the experiment in lab. Print the worksheet and bring it with you to the lab.