Hydrolysis LabSetup

Tahoma Jr. High8th Grade ScienceMaple Valley, WA

2,000 years ago, the Greeks (who were very smart and curious about Nature) would just observe and discuss possible logical

reasons why Nature was what it was.

They didn’t do actual experiments really – because they thought their reasons were good ones since the

evidence was obvious.

The Sun and Moon and stars obviously go around the Earth, right?

You can see that yourself, right?!

They thought that all matter (stuff) in the Universe was made of only Four Earth Elements:

earth (dirt)*can’t grow plants

without it

air*you can feel

wind push you

fire*is obviously

there and changes things

water*water comes out of you when you sweat, out of

grapes, apples, etc.

It’s “obvious” that all things you see can be made in different

combinations of these four Earth Elements, right??

Here’s the Greeks’ first Periodic Table of the Elements

Get it – the four Earth Elements?!

Well, we’re going to do a “simple” experiment that proves them wrong – and that just sitting around

thinking about things isn’t good enough!

You HAVE to do controlled EXPERIMENTS

(though it would have been hard for them to do what we’re going to do because electricity hadn’t

been “discovered” yet!!)

Hydrolysis

hydro = water

lysis = splitting

What is the chemical formula for water?

That’s right! H20

The formula H2O means there are two hydrogen atoms for each oxygen atom.

How can we prove this?

Let’s add some energy to break the bonds holding the hydrogens and oxygen together.

HYPOTHESIS:

IF electricity is used to break water (H2O) apart, THEN one bubble of the gases

produced will be twice as big as the other bubble BECAUSE the formula H2O shows that there are two hydrogen atoms for

every one oxygen atom.

Procedure:1. Fill beaker 1/2 full of water 2. Fill test tubes completely full of water3.Put finger over end of test tube and turn it upside downinto beaker, making sure that no air enters the test tube(a very small bubble is OK). Do same with other test tube. Tubes without bubbles are one good Controlled Variable.

Procedure (cont’d):4.Place the electrodes into the water and gently put the filled test tube over the exposed end of the electrode. Do this with the second electrode and tube as well.

Procedure (cont’d):

5.Connect the red clip from the battery eliminator to one of the electrodes and the black to the other.Use the cardboard to avoid the clips contacting each other!

Procedure (cont’d):

6. Slide the switch on the battery eliminator to 12V and polarity switch up (although this doesn’t really matter).

Don’t plug in!!

Voltage Switch(polarity switchis on this side too.

Also, if you have a switch on the back for 120V or 240V, put it on 120V

(other countries often use 240V)

Procedure (cont’d):

7.Put the setup on the counter and call teacher to add acid. Only after your teacher checks your setup and has added acid will they tell you “OK, plug it in.”

Procedure (cont’d):8. Occasionally agitate the water in the beaker with pipette to keep the gas production at its peak. Observe the end of the electrodes and see if anything is happening.9. When one of the tubes becomes full of gas, unplug the battery eliminator.

After you record Results/DataCLEAN UP and RETURN YOUR EQUIPMENT

…then finish the Conclusion, Evaluation and New Question

as you think you should.

K-W-L(we want to see what you “KNOW”)

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