CHEMISTRY ACTIVITIES

Times listed for each lab activity are approximate times. Times include set-up/take down of equipment and discussion of data collected. Lengthy labs can be spread over several days.

Quantitative Analysis of Vitamin C in Food and Drink - Students use a known concentration of vitamin C (vitamin C tablets or ascorbic acid) to prepare a serial dilution. A spectrophotometer is used to prepare and absorption curve (standard curve) and students use their graph to identify the amount of vitamin C in an unknown. Time 60-70 minutes.

Vitamin C analysis of food and drink- A quantitative analysis - Students use a known concentration of vitamin C (250 mg vitamin C tablets) to prepare serial dilutions and then use both the spectrophotometer and iodine titration to develop standard curves. Students use these standard curves to determine the amount of vitamin C in unknowns.

Time 60-90 minutes, depending on whether one or both analyses are done.

Seeing the unseen - Radioactive particles and rays - Use of a cloud chamber (requires dry ice) to visualize alpha, beta, and gamma emission from a radioactive source. Time 45-50 minutes.

Nuclear medicine lab - Use of the radiation monitor to scan the head of a mock patient to locate a brain tumor. Students use the monitor to search for a "hot spot" created by absorption of a radioisotope into the tumor. Time - 30 minutes.

Investigating energy levels of hydrogen - Balmer series- Use of the spectroscope to calculate the wavelengths of the bright-line spectrum produced by hydrogen. Time 50-60 minutes.

Exploring Light - Students use spectrometers to investigate emission, absorption, and continuous spectra. Light sources include an incandescent bulb, fluorescent tube, and elemental spectra tubes (H2, He, and Ne). Time 50-60 minutes.

Stellar Spectroscopy - This lab demonstrates one application of spectroscopy. Students are provided the Balmer lines of hydrogen from the spectra of a star. The wavelengths observed in the star are compared to the wavelengths produced by a hydrogen gas discharge tube observed through a spectroscope in lab. The differences in wavelengths are used to calculate the radial velocity of the star. Time 45-50 minutes.

Criminalistics (Forensic Science) - A Powerpoint program takes students through a mock crime scene, including diagrams of the crime scene, police reports, suspect interviews, etc. Evidence that has been collected at the crime scene is then analyzed by students. Once students have analyzed all of the evidence, they file an arrest warrant against one or more of the suspects. Evidence analyses include hair analysis, fingerprint analysis, blood typing, DNA fingerprinting, drug testing using thin-layer chromatography, pill analysis using a PDR, and liquid analysis using a gas chromatograph. This is an excellent lab for a combined chemistry/biology/physics group of students. Time - 3-4 hours. There is no written lab for this activity.

LAB ACTIVITIES USING VERNIER LAB PRO SENSORS (from the Vernier manual Chemistrywith Computers.)

Experiment # and title:

• Endothermic and exothermic reactions - Use of the temperature probe to measure temperature changes when various chemicals are added to water. Time 45-50 minutes.
• Freezing and melting of water - Use of the temperature probe to measure the freezing/melting temperature of water. Time 45-50 minutes.
• Another look at freezing temperature - Use of the temperature probe to measure the freezing point depression of two different chemicals. Time 45-50 minutes.
• Heat of fusion for ice - Use of the temperature probe to determine the energy required to melt one gram of ice. Time 50-60 minutes.
• Find the relationship: An exercise in graphing analysis - This activity contains 25 problems where students use Logger Pro to graph a variety of mathematical relationships. This is a good lab to teach students how to make and interpret graphs. Time 50-60 minutes.
• Boyle’s Law: Pressure-volume relationship in gases - Use of the gas pressure sensor and a 20-mL syringe to discover the relationship between pressure and volume of gases. Time 30-40 minutes.
• Pressure-temperature relationship in gases - Use of the gas pressure sensor to discover the relationship between pressure and temperature of gases (Charles’s Law). Time 40-50 minutes.
• Evaporationand intermolecular attractions - Use of the temperature probe to measure the rate of evaporation of various liquids and relate the rate of evaporation to the strength of intermolecular forces of attraction. Time 45-50 minutes.
• Vapor Pressure of Liquids - Use of the gas pressure sensor and temperature probe to investigate the relationship between vapor pressure of a liquid and its temperature. Time 50-60 minutes.
• Determining the concentration of a solution: Beer’s law - Use of the Vernier colorimeter (this lab can also be done with the Genesys 20 spectrophotometers) and NiSO4 solution to develop a standard curve and to then use the graph to determine the concentration of an unknown concentration of NiSO4. Food coloring can also be used for this lab. Time 50-60 minutes.
• Effect of temperature on solubility of a salt - Use of the temperature probe to determine the effect of temperature on the amount of solute that will dissolve in water. Time 45-50 minutes.
• Properties of solutions: Electrolytes and nonelectrolytes - Use of the conductivity probe to observe the behavior of ionic compounds, molecular compounds, and molecular acids in aqueous solutions. Schools must provide the chemicals for this lab. Time 45-50 minutes.
• Conductivity of solutions: The effect of concentration - Use of the conductivity probe to study the effect of increasing the concentration of an ionic compound on conductivity. Time 45-50 minutes.
• Using freezing point depression to find molecular weight - Use of the temperature probe and the formula DT = Kf m to find the molecular weight of benzoic acid. Time 45-50 minutes.
• Energy content of foods - Use of the temperature probe and a simple calorimeter (Styrofoam cup) to measure the energy released (in kJ/g) as various foods are burned. Should be done in a well-ventilated classroom. Time - 50-60 minutes
• Energy content of fuels -Similar to #16 only using fuels such as paraffin wax and ethanol.

Time - 50-60 minutes.

• Additivity of heats of reaction: Hess’s Law - Use of the temperature probe and a simple calorimeter to measure the heat released by three chemical reactions and to observe the concept of additivity of heats of reaction. Schools must provide the chemicals for this lab. Time 50-60 minutes.
• Heat of combustion: Magnesium - Use of the temperature probe and a simple calorimeter (Styrofoam cup) to determine a heat of reaction that would be difficult to obtain by direct measurement. Time 45-50 minutes.
• Chemical equilibrium: Finding a constant, Kc- Use of the Vernier colorimeter to determine the equilibrium constant for the reaction Fe+3(aq) + SCN-1(aq)ßà FeSCN+2(aq) Time 50-60 minutes.
• Household acids and bases - Use of the pH probe, pH paper, and red cabbage juice to measure the pH of common substances such as vinegar, ammonia, detergent, and baking soda. Time 50-60 minutes.
• Acid rain - Students produce four acids, carbonic, nitrous, nitric, and sulfurous. Students use the pH probe to measure the change in pH as these acids are produced in water solution. This would be an excellent lab for an environmental science unit in biology, earth science, or in an environmental science class. Schools must provide the chemicals for this lab. Time 50-60 minutes.
• Titration curves of strong and weak acids and bases - Use of the pH sensor and burettes to combine acid and base combinations and measure pH changes as the solution reaches its equivalence point. Schools must provide the chemicals for this lab. Time 50-60 minutes.
• Acid-Base titration - Use of the pH sensor and burettes to determine the unknown concentration of a solution of HCl. Time 45-50 minutes.
• Titration of a diprotic acid: Identifying an unkown - Use of the pH probe and burettes to identify an unknown diprotic acid by finding its molecular weight. Unknown acids include oxalic, malonic, maleic, malic, and tartaric. Schools must provide the chemicals for this lab. Time 50-60 minutes.
• Using conductivity to find an equivalence end point - Use of the conductivity probe and burettes to monitor conductivity during the reaction between sulfuric acid and barium hydroxide in order to determine the equivalence point. Schools must provide the chemicals for this lab. Time 50-60 minutes.

28. Establishing a table of reduction potentials: Micro-Voltaic cells - Use of the voltage probe to establish the reduction potentials of five unknown metals relative to an arbitrarily chosen metal by measuring the potential difference between various pairs of half-cells.

Time 50-60 minutes.

LAB ACTIVITIES USING THE VERNIER RADIATION MONITOR (from the Vernier manual Nuclear Radiation with Computers and Calculators.)

All of the radiation labs use radiation sources that are safe for students. The alpha source is

Polonium-210, the beta source is Strontium-90, and the gamma source is Cobalt-60.

Experiment # and title:

• Alpha, beta, and gamma - Students use the radiation monitor to measure the effect of shielding on the various types of radiation. Shielding materials include such materials as paper, cloth, cardboard, tin, and lead.
• Distance and radiation - Students use the radiation monitor to measure the effect of distance on the various types of radiation. Students then prepare graphs of their data.

Note: Labs 1 and 2 can be done simultaneously in 50-60 minutes.

6. Radiation shielding - Students use layers of cardboard and a radiation monitor to measure the amount of beta radiation absorbed by the cardboard. Time 30-40 minutes.