Penny%For%Your%Thoughts% An%Introduction%to%Chemistry ...

Penny For Your Thoughts

Name: _______________________

An Introduction to Chemistry

Date: ________________________

Purpose: To observe a chemical transformation firsthand.

Period:_______________________

Your instructor will guide you through an experimental procedure. Be sure to pay close

attention to your instructor's directions.

This procedure uses dangerous chemicals.

Do not proceed to the next

step until instructed to do so.

Goggles are required for this lab.

You are also required to tie your hair back.

Before we begin, please answer the following questions.

List the equipment we will use in this lab:

1. ___________________________________ 5.

___________________________________

2. ___________________________________ 6.

___________________________________

3. ___________________________________ 7.

___________________________________

4. ___________________________________ 8.

___________________________________

Safety is extremely important in the chemistry lab.

In the space below, write three important safety considerations for this experiment.

1

2

3

Procedure Part 1 1. Using weigh paper, mass out 6.0 grams of zinc filings in a 150 mL beaker to cover the bottom.

(This may have

been done for you.)

2. Carefully add 15 mL of 3M sodium hydroxide (NaOH) to the same beaker. 3. Place the 150 mL beaker on a hot plate which has been set to "3".

If the liquid begins to boil, turn down the

setting on the hot plate down to "2". 4. Use your tongs to pick up the penny and place it in the beaker. If you are working in pairs, put both pennies in

and let it sit for 1--2 minutes. 5. While the penny is warming up, put 200 mL of tap water into a 250 mL beaker. 6. One the penny is coated, remove it with the tongs. Make sure your teammate uses the other set of tongs to

hold the hot beaker still while the penny is removed.

7. Put the hot penny in the 250 mL beaker, which is filled with tap water.

This serves to cool and rinse the

penny.

8. Turn the hot plate off

Part 2

1. Set up and light the Bunsen burner according to your teacher's directions.

2. Adjust the flame on the burner using the metal collar.

A blue flame is hotter than a yellow or orange flame.

3. Use your tongs to place the "silvered" penny above (not into) the flame of the Bunsen burner. (Too much heat

can warp and destroy your penny!)

4. Hold the penny in the flame only until it changes color, and no longer. Pay attention, it happens quickly

(within 10 seconds)!

5. Once the penny has changed color, place it in the beaker of water to cool.

6. Turn the flame off.

Part 3

1. Follow your instructor's directions regarding the beaker of sodium hydroxide and zinc.

2. Do a general clean up of the lab area.

3. Wash your hands with soap.

During the lab

Procedure

Observation

Place the beaker with zinc and Zinc covers the bottom of the beaker. The sodium hydroxide is a

sodium hydroxide on a hot plate and clear colorless liquid that fills the beaker about half way. During

set the hot plate to 4.

If the liquid heating, there is a slightly putrid odor and bubbles form.

begins to boil, turn the hot plate

down a little.

Use tongs to place the penny in the

heated beaker.

After a few minutes,

remove the penny with tongs.

Put the hot penny in the beaker of

cold water to cool and rinse it.

Use tongs to place the penny into

the flame of the Bunsen burner.

When the penny has changed color,

place it in the beaker of cold water

to cool again.

In the table below, briefly describe your observations of each chemical used in the experiment.

The first one has

been done for you.

Chemical

Observation

Penny

Shiny, reddish--brown, cylinder--shaped solid

Zinc

3M Sodium hydroxide

Water

After you are done

Working with the students at your table, spend a few minutes discussing descriptions of what you observed during the experiment.

Then, answer the questions individually on binder paper.

Write each question on your paper.

Use complete sentences.

1. Describe what happened to the penny during the experiment.

2. What do you think turned the penny silver? 3. What do you think happened to turn the penny gold? 4. Do you think you made real gold?

Why or why not? How could you find out?

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