Foundational Level General Science Laboratory Descriptions
Chemistry 3012 Foundational Chemistry Laboratory Manual
Determining the Density of an Unknown Liquid
Students determine the density of an unknown liquid by manipulating the density of an object (the flask) that will be placed in that liquid. In order to determine the initial density of the object, students determine the mass and volume of that object. In Part 1 of the experiment, students use the mass of the flask and an initial estimate of the volume to determine how much sand needs to be added to the flask in order for the flask’s density to match that of water. Students will then add or subtract sand until the flask is suspended in the fluid, as defined by the point at which it takes more than three seconds for the flask to either rise to the top of the fluid or sink to the bottom. Once equal density is established, students will determine a more precise volume for the flask using the mass of the flask and sand along with the known density of water. In Part 2 of the experiment, students manipulate the mass of the sand in the flask, along with the precisely known volume of the flask to determine the density of an unknown liquid.
Development of the Periodic Table: Part 1
In this lab, students organize a group of cards in a logical manner. There are four variables students utilize in making their ordering choices; some variables are more helpful than others, but once complete, the grouping of cards as a whole should follow patterns. To challenge students, one of the cards has been removed. In addition to solving the overall pattern, students determine the properties of the missing card.
Development of the Periodic Table: Part 2
In Part 1, students observed how patterns in the properties of elements could be used to construct a useful table for organizing and communicating these properties. In Part 2, students experimentally determine the order in which a series of these elements should lay in the periodic table. The elements in a vertical column in the periodic table are referred to as a family or group, and their physical and chemical properties are similar, though they gradually change up and down that group. The two groups students experiment with are the alkaline earths (Group 2) and the halogens (Group 17).
In this lab, students determine the amount of energy stored in a peanut through calorimetry. To facilitate this measurement, students first build an inexpensive calorimeter, a device that is used to measure the transfer of heat energy during a chemical or physical change. The calorimeter will be fashioned from a soda can, to which you will add water. Students deduce the amount of energy transferred to the can. Assuming that all the energy absorbed by the calorimeter originated from the peanut, students calculate the amount of energy released per gram of peanut consumed (not all of the peanut will be combusted). In Part 2 of this experiment, students determine the amount of electrical energy that is required to obtain the same temperature increase they observed in Part 1. The device used will deliver power (Watts = J/second) to the heating filament. To obtain the energy that was needed to heat the filament, the duration (in seconds) of how long that power was used needs to be recorded.
Electronic transitions between energy levels give rise to the wavelengths in the atomic spectrum of hydrogen. These wavelengths are also known very accurately. Given both the energy levels and the wavelengths, it is possible to determine the actual levels associated with each wavelength. In this experiment, students make determinations of this type for the observed wavelengths in the hydrogen atomic spectrum. In Part 2, students observe and record atomic line spectra from discharge tubes located in the lab and conduct flame tests on unknown salts. Based on the observed line spectra of gaseous samples and colors of heated solid samples, students will determine the identity of the gases and solids, respectively.
Synthesis of Soap
In this experiment, students prepare soap from animal fat (lard) through saponification. Students evaluate the properties of the soap they synthesize. In part 2, they use the soap they have made and a paper boat to learn how surfactants break the surface tension of the water.
In this lab, students represent the electron domains as balloons, which will be tied together at a location that represents the central atom, and use molecular model kits to represent a variety of molecules. Students will draw Lewis structures applying rules in the proper order. They will gain practice with predicting different electron and molecular geometries and identifying resonance structures and instances of molecular polarity.
This is the capstone project of the course. Students are challenged to design a simple water filtration system given a variety of materials and chemicals that use the processes of filtration, chemical adsorption, and precipitation to purify “dirty” water. The success of the purification process is evaluated based on appearance, odor, pH, and conductivity.