Department of Chemistry
There are several parts to this lab. The objective of Part I, which is the prelab assignment, is to use a software program to gather information about a variety of periodic trends from a database. The objectives of Parts II and III are to observe the acid-base properties of several elemental oxides and the oxidizing ability of the elemental halides, respectively. Then, based on the observations and data collected, the periodic trends for the periods and groups investigated will be determined.
In Part I, the program "KC Discoverer" will be used to plot several periodic properties as a function of group and/or period to see what the trend is among the elements on the periodic table. Based on the results of the database searches, you will answer questions and sketch plots on the pre-lab report worksheet.
In Part II, the acid-base indicators phenolphthalein and bromothymol blue will be used to test the acid-base properties of several elemental oxides (such as the brown NO2 gas in the beaker shown above). Based on the findings, the periodic and group trends for acidity and basicity will be determined.
In Part III, the oxidizing ability of the elemental halides will be determined. By reacting chlorine (Cl2) with ions of the other halides (bromide, Br-, and iodide, I-) the ability of Cl2 to oxidize Br- and I- will be determined. The reaction between bromine and iodide will also be observed. Based on the observations of each halide's ability to oxidize or reduce the others, the trend within the group will be determined.