• UNL
• Arts & Sciences
• Department of Chemistry
• Resource Center
• Chem 109 Lab Connections

Department of Chemistry

Chem 109 Lab Connections

1. Microsoft Internet Explorer will open ".DOC" files inside the browser. Therefore, MSIE users should save .DOC files to your own computer, then open them with Microsoft Word.
2. Non-Microsoft browsers will probably open .DOC files using Word if Word is installed on your computer.
   ".DOC" files require Microsoft Word.
   ".PDF" files work similarly but require Adobe Acrobat Reader.

Week 1:

The lab session this week has three goals. First, we want you to be familiar with all the specific, unique safety concerns with doing chemistry experiments. UNL chemistry does enjoy a good safety record, so pay close attention to the safety procedures and rules. Secondly, this session is where you conduct an inventory of your supplies. You are responsible for the glassware and other supplies checked out to you, so make sure your assigned lab cabinet has all the required materials. Then we will have you conduct a short experiment where we look at the differences between chemical and physical changes.

Week 2: Becoming a Scientific Detective

As you perform this investigation be sure to reinforce your understanding of chemical and physical properties. Also, note that compounds may be separated from each other if they have been previously mixed together. Separating mixtures can sometimes be a fairly straightforward procedure. However, separating a compound into its elements is not so easy.

In part two of the investigation you get to make a couple of interesting substances and investigate their properties.

Week 3: Density

When performing this week's experiment on density, think about what kind of property density is. Is it an intensive or extensive property? Is it a chemical or physical property?

When collecting your data, pay attention to significant figures. Do you remember the rules about zeros? Many things we discuss in lecture are important for a good laboratory experience. Be thinking about these things as you further your understanding of density.

Week 4: Recycling Aluminumfor Aluminum Scrap

In lab this week, you will be using aqueous solutions of strong bases and strong acids. Think about what properties these substances have and how they react with the aluminum you will be using. Also, think about precipitation and how and why it occurs in this experiment. There are many sequential reactions that you will carry out this week. You should be able to understand them and note the detailed manner of how they are balanced. You will be calculating theoretical and percent yields. The end of chapter four can help you with these calculations. This week you will be synthesizing a useful chemical product (alum) from scraps of used aluminum. Chemical reactions are a form of "atomic recycling." This is exactly what we have been doing in lecture when we balance an equation and use staring amounts to predict the amount of product we could.

Week 5: How Antacids Work in the Stomach

One of the major classifications of chemical reactions is the acid-base reaction. You will experiment with the antacid-stomach acid reaction. Pay careful attention to the overall scheme of the reactions. For example:

Acid + base = salt + water
Acid + carbonate = carbon dioxide + other

You will also be applying the concept of molarity to some of the solutions in this lab.

Week 6: Chemical Reactions (Quiz 1)

As you have been studying chemical reactions in lecture, you will now apply that theory by actually doing, in the lab, redox, acid-base, and precipitation reactions. Pay particular attention to the type of reaction and the particular clues that go with it.

Week 7: Molar Mass of Butane

This week we are gathering the experimental data for the the PV=nRT equation. You will get the opportunity to see that the mathematical representations do have an experimental basis. What if you have trapped a known number of grams of an unknown gas in a known volume (use L) at a known temperature (use K) with a known pressure (use atm)? Can you determine the molar mass? Note how we discussed this in lecture. (The unknown gas is butane..... how many grams are in a mole?)

Week 8: Water Analysis

In lab this week you will be performing a titration using a known concentration of EDTA on a sample of water that you WILL BE BRINGING to lab to determine the concentration of ions in your sample, such as Ca+ and Mg2+. To determine the concentrations of ions in your water you will be employing the process of titration. Titration is a useful method for determining small concentrations in an aqueous sample by its reaction with another added agent of known amount until the equivalence point is indicated by an appropriate indicator. REMEMBER that there is a difference between end point and equivalence point. Which of these will you be using when you do your calculations?

Week 9: Hess' Law

This week in lab you have the opportunity to apply what you have learned about thermodynamics in particular Hess's law, specific heat, and calorimetery. Remember in lecture how heat absorbed or released by a system can be calculated as; q=mass*specific heat*
Also, recall how a series of reactions and their enthalpies can be manipulated to obtain the enthalpy of a target reaction.
The way that is connects to lecture is that you will make your own calorimeter and do a series of actual thermo chemical experiments.

Week 10: Patterns of Periodicity

In lab this week you will gather experimental evidence of periodic trends. One of the trends deals with solubility, you will compare group II (2) metals and the solubility of their ions be able to explain the trends you see. The other trend is one we covered in class on October 19th dealing with metal and nonmetal oxides, use your class notes to help answer lab questions about the metal and nonmetal oxides.

Week 11: Modeling and Chromatography

For this week's lab you will perform a common type of chromatography called Thin Layer Chromatography or TLC to explain polar properties of various compounds.

Week 12: Aspirin Week 1 (Quiz 2)

During the first week of this lab you will synthesize aspirin. Salicylic acid and acetic anhydride will be the reactants but will also serve as a catalyst. A catalyst increases the rate of the reaction but is not consumed during the reaction. The initial product will be impure. In order to purify the aspirin crystals, a recrystallization process will be performed.

Week 13: Aspirin Week 2

This week you will finish the Aspirin lab that you started last week. The primary goal being to use titration to determine the synthesized aspirin's purity.

Week 14: Practical (Aspirin Report Due)

Week 15: CHECK-OUT

Back to top