Part I — Physical Change
Obtain a nichrome wire from the lab cart. Note its physical appearance. Get a Bunsen burner from the lab cabinet. Take it apart and note the following parts: barrel, carburetor, gas control, and base. In your lab book draw and label the parts of a Bunsen burner. Put the burner back together and light it.

Place the nichrome wire (which should be about fifteen centimeters long) in the flame and note whether or not it glows. Using the wire, determine where the hottest portion of the flame is. Can you find a cone of gas within the flame that is not yet on fire?

Place a piece of copper metal in the flame of the burner for a couple of minutes. Note its physical appearance before and after heating.

Part II — Chemical Change
Hereafter you will be using labware from your lab drawer. In order for the experiments to work correctly your labware must always be clean and dry before being used in an experiment. Also take great care to use only the chemicals called for in an experiment.

A. Reaction of Magnesium. Weigh a crucible and lid to the nearest hundredth of a gram, add about a quarter gram of magnesium metal to the crucible, and weigh again. Support the crucible on a clay triangle and place the lid on the crucible at an angle so that the magnesium is exposed to the air. Heat gently until the bright glowing of the metal no longer is evident. Cool the crucible and lid for five minutes and weigh again. If the magnesium metal fails to glow, heat it more strongly. Use a table such as the following to record your data in your lab book (left-hand page).

B. Percent Composition. Use your data from the reaction of magnesium, and the calculations outlined in the following table, to determine the percent composition of magnesium oxide (MgO) prepared in A above.

C. Dehydration. Carefully weigh a clean, dry evaporating dish. Add about two to three grams of the blue colored chemical and weigh again. Heat the chemical until a uniform color appears, cool and weigh again. Heat a second time for a few minutes and cool and reweigh. A constant mass indicates that the removal of “water of hydration” is complete. Calculate the percent water in your sample, following the steps in the following table.

Part I — Physical Change
Draw a diagram of the Bunsen burner flame and use it to answer the first two questions.

1. The hottest portion of the flame is located where?
2. The cone of gas not on fire is located where?
3. Have the physical properties of the wire changed?
4. Did the copper metal undergo a chemical or physical change, or both?

Part II — Chemical Change
A. Reaction of Magnesium

1. Explain the fact that the mass of the product was more than the mass of the reactant Mg.
2. What pieces of evidence demonstrate that the Mg has undergone a chemical change?

C. Dehydration

1. Explain the change in the mass of the substance during heating.
2. Was the change chemical or physical, or both? Why?

Finally, obtain the actual percents of magnesium and oxygen in magnesium oxide, and the percent water in your hydrate, and calculate your percent errors.