Forces and Bonding: The Liquid Project

• To provide a long-term research project involving a number of aspects of chemical identification, structure, and reactivity
• To enhance observation skills
• To learn and reinforce techniques of synthesis, separation, and characterization
• To enhance skills of experimental design and strategy

The purpose of this project is to give you a long-term, research-like laboratory experience in chemistry. Unlike the 1-period experiments that you have performed during previous terms, this project will occupy the entire term, and will be conducted at your pace and according to your experimental decisions. Instructors will be on hand to provide help and guidance; however, the responsibility for advancing the project to a meaningful conclusion will be yours.

Before coming to lab each week, you should complete the appropriate set of Preparation Questions and hand them in at the beginning of the period, as usual. We expect that you will maintain your laboratory notebook in the same manner as in previous terms; however, the notebook will not be turned in for grading. Instead, you will be expected to submit a formal research report on your findings at the end of the term. Your laboratory grade will be based on the quality of this report, and on the Preparation Questions that you answer each week.

Description of Project You will work with a partner throughout the term. At the first lab period, you and your partner will be given a sample of a common liquid. You must then proceed, during the successive weeks of the term, to address the following project objectives:

• Identify your liquid
• Determine the physical properties of your liquid. These include
  • Color
  • Conductivity
  • Boiling point
  • Freezing point
  • Equilibrium vapor pressure at at least 3 temperatures. This will allow you to determine
    • Enthalpy of vaporization
    • Entropy of vaporization
  • Density
  • Molar mass
  • Miscibility with common liquids (water, acetone, ethanol, dichloromethane)
  • Solvating ability
• Determine the reactivity of your metal with water; with dilute (6 M) acid (e.g., HCl). This includes
  • Isolation and identification of gaseous products
  • Isolation and identification of dissolved products
  • Determine whether the dissolved product is ionic or covalent
  • Analysis of the dissolved product for chloride content to determine the oxidation state of the metal
  • Measurement of the molar enthalpy of reaction of your metal with aqueous HCl
• Determination of the Lewis acid properties of the cation of your metal. This includes
  • Determination of the pH of a 0.1 M solution of the chlorine compound of your metal
  • Study of the solubility of salts of the cation of your metal with various anions (e.g., Br-, SO₄^2-, S^2-, CO₃^2-, PO₄^3-, others)
  • Synthesis of the complex of the cation of your metal with ammonia, NH₃
  • Characterization of the ammonia complex. This includes
    • Color
    • melting point
    • Solubility in common solvents
    • infrared spectrum
    • UV-visible spectrum
    • Spectrometric Analysis of the ammonia complex
  • Structure of the ammonia complex
• Determination of the redox properties of your metal. This includes
  • Position in the activity series of metal
  • Accessible oxidation states of your metal

Preparation Questions

1. Week 1
2. Week 2
3. Week 3
4. Week 4
5. Week 5

Equipment and Materials

• assorted beakers and Erlenmeyer flasks
• Pasteur pipets/bulbs
• assorted watch glasses
• Product vials (1-dram)
• 5- and 10-mL volumetric flasks
• 1-, 2-, 5-, and 10-mL graduated pipets
• Syringe pipet pumps
• spatulas
• balances
• aspirator trap
• filtration equipment (sidearm test tubes, Buchner funnels, filter paper, funnel collars)
• Conductivity meter components (batteries, LEDs, perf-board, resistors)
• metals
• Stock NaOH solution (about 6 M)
• Stock HCl solution (about 6 M)
• conc HNO₃
• potassium hydrogen phthalate
• pH meters
• pycnometers
• 25-mL burets
• Cu(NO₃)₂.6H₂O
• Ni(C₂H₃O₂)₂.4H₂O
• Melting point capillaries
• Rock salt
• Infrared spectrometers
• Infrared sample preparation equipment
• UV-visible spectrometers
• UV-visible cuvets
• NMR spectrometer
• NMR sample preparation equipment

Safety goggles must be worn at all times in the laboratory. Avoid contact of the reagents with the skin. In the event of skin contact, flush the affected area with copious quantities of cold water.

Record all data and observations in your notebook.

Design of experiments is up to you.

Clean-up. When you have finished all of your work each week:

• Clean glassware by recommended procedures, shake off excess water, and return to the Labkit.
• Clean Pasteur pipets, graduated pipets, and vials by recommended procedures, shake off excess water, and place in the drying oven.
• Return all borrowed equipment to the instructor before leaving lab.
• Clean up your work area before leaving lab.

Dispose of all solids, liquids, and solutions in the appropriately marked waste bottles.