Dry Ice Experiments

Bright Light

You will need:

• welders goggles for the person lighting the magnesium.
• heavy gloves of leather or fabric--not plastic or rubber.
• magnesium ribbon about 12 inches or 30 cm long crumpled into a ball.
• 2 dry ice blocks about 8 inches square and 3 inches thick.
• propane torch or bunsen burner to light the magnesium

Procedure

1. Note: Remove anything that burns from the area and put the ice on a non-combustible surface like a road.

   Do not look directly at the light unless you are wearing dark colored welders glasses because the ultraviolet light will destroy your vision.

   Wear the gloves for the rest of the procedure.

   Put on eye protection.

   Scoop out a 1 inch deep and 2 inch wide depression in the middle of both dry ice blocks.

   Put the magnesium ball into one depression and set it on fire.

   Place the other piece of dry ice on top of the burning magnesium with the depression facing downward and above the magnesium.

You can purchase magnesium from many supply houses. Dry ice can be purchased at welding supply stores. Other places can be determined by calling emergency services or your utility company.

Magnesium reacts with the carbon dioxide gas to form carbon (black specks) and magnesium oxide (a white powder).

2 Mg_(s) + CO_{2 (g)} ----> C_(s) + 2 MgO_(s)

Eudiometer

A eudiometer is used to measure the volume of a gas by displacement; in our case without an explosion. I made a large eudiometer out of a plexiglass cylinder 12 inches in diameter and glued plexiglass squares on each end. One hole was placed in the top square that could be sealed with a large stopper. At the base of the cylinder about one inch up on the side was another hole that could be sealed with a large stopper. Calibrate the eudiometer. Also needed was an aquarium that will hold the eudiometer. With this device I could measure a mole of gas.

1. Do this experiment outside.
2. Immerse the unstoppered eudiometer into an aquarium half filled with water.
3. Stopper the bottom hole in the eudiometer and fill the eudiometer with water to the top.
4. While wearing gloves put one mole by weight of dry ice quickly into the eudiometer and stopper the top hole. Immediately unstopper the bottom hole.
5. Measure the amount of gas produced after all the dry ice disappears

CO₂ Gas Demonstrations--

wear gloves:

• Half fill a plastic shoebox or bowl, etc. with water. In the shoebox or bowl turn a beaker or baby food jar upside down that is filled with water so no air is inside. Toss a small piece of dry ice into the water and cover it with the opening of the beaker or jar.

• Put a small amount of dry ice into a balloon and watch it expand.

• Put some dry ice into a trough and pour the gas onto a candle flame.

• Mix liquid soap with warm water and then drop in dry ice.

• Accurately weigh a one liter bottle to the nearest 1/100th gram. Subtact the weight of air (1.29 grams) from the bottle weight. Put some dry ice into the bottle and when it is all disappeared reweigh the bottle. Determine the molecular weight based on this experiment.

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