Name: ______Date: ______Period: ______

Experimental Observations

Background:

Chemistry, like other sciences, is based on observation and experiment. It concentrates on the properties, composition, and structure of matter and the changes that matter undergoes. The observations and interpretations of chemical changes are basically what chemistry is all about. In this activity, you are to record your observations and decide which perceptible changes might indicate that a chemical reaction has occurred. Every chemical reaction results in the production of one or more substances (products) which are different from those present at the beginning of the reaction (reactants).

Objectives:

When you have completed this activity, you should be able to:

  1. Describe the results of mixing pairs of materials.
  2. Describe four indicators of a chemical change.
  3. Describe the purpose of an experimental control.

Materials:

Solution samples, numbered 1-4, in dropping bottles

Metal sample

Test tube rack

Test tubes

Waste beaker

Safety Information:

Goggles and aprons must be worn at all times during the experiment.

Dispose reactions with the metal in the waste beaker – not down the sink.

Mission:

There are 5 chemicals (4 solutions and 1 metal). You will observe each one individually to serve as a control. You will react two chemicals at one time and continue with a new pair until all possible combinations have been satisfied. 20 drops of solution will be used for each trial. 1 “chunk” of metal will be used for each trial.

Procedure:

As a group, write a detailed, step-by-step procedure to carry out this mission. Below are some questions to consider when creating the procedure and example of how to start off your procedure.

Questions:

  • Do you need to record the controls first or last?
  • How many drops of each solution do you need?
  • How much detail do you need?

Part 1: Controls

  1. Number five clean test tubes 1-5.
  2. Place 20 drops of Solution 1 in test tube 1. Record your observations in the control data table.
  3. ………. (you will finish writing the procedure)

Part 2: Chemical Reactions

  1. Reactions with Sample 1.
  2. Number four clean test tubes 2-5.
  3. Place approximately 20 drops of Sample 1 in test tubes 2-5.
  4. Place approximately 20 drops of Sample 2 to tube 2 and shake gently.
  5. Record your observations in Data Table 2 after each reaction.
  6. Repeat by adding Sample 3 to the test tube 3.
  7. …………(you will finish writing the procedure)

NOTE: Above are just examples of how you can write your procedure. If you want to change the wording, you may, but just remember that it must be clear about what you are trying to accomplish.

Data Table

You will create 2 different data tables for this lab. One will be a control data table where you will record your observations before reacting with any other sample. The other will be where you record the observations when you reach two solutions together. Below are some questions to consider when creating data tables.

Questions

  • How will you represent what you are reacting?
  • Do you need a title?

Analysis

As a group, after you have done the experiment, answer the following in complete sentences. Remember, if you do not agree with your group, you may submit your own lab report.

  1. Which pairs of materials produced a chemical reaction?
  2. What evidence do you have that chemical reactions took place? (Describe the four indicators for chemical change)
  3. What was the purpose of setting up the controls in Part 1?

Turn In

In this order, turn in the analysis, procedure, and data table. All group member’s name must be on the document. All documents will be turned in via OneDrive through Office 365.