Yeast Beasts in Action

Pressure of the 3 tests. (acid-red, neutral-blue, base-green)

Pressure of the first 2 tests. (acid-red, neutral-blue)

Pressure of the first test. (acid-red)

Which creates the most pressure when mixed with yeast, an acid, a neutral, or a base?

Base!

What was done to get that answer:

We got 3 test tubes on a rack and labeled them A, N, and B. Then we placed 3 mL of of hydrogen peroxide into each test tube, using a dropper. The test tubes each got a similar reactant and a different reactant. In the test tube labeled A we placed an acid, in this case we used diet soda . In the test tube labeled N we but used a neutral reactant, milk. And in the test tube labeled B we placed a base, antacid.

Once this was done we placed 2 drops of the yeast suspension, water and yeast, in the first test tube, A, and placed the one hole stopper on top. We collected information for two minutes. We repeated this with the other two test tubes as well.

A:

When test A was first mixed the mixture was cloudy and had some bubble, which could have been carbonation.

N:

When test N was mixed not much happened. Then when we did the pressure test the pressure rose at about the same pace test A had. We noticed that at the end of testing it with yeast the mixture had a thick layer of bubbles on it.

B:

The air pressure rose ate the same speed as the other tests. A thin layer of bubbles formed on the top of the mixture.

Hypothesis:

If we mix an acid, a base, and a neutral reactant with yeast and see which has the most pressure, then the acid would have the most pressure. I think that the acid would create the most pressure because the soda-hydrogen peroxide mixture will break down the yeast and release the gas that is in the yeast.

Is this right?

No!

Why?

Pressure:

Acid:

Start pressure- 101.31

End pressure- 106.2

Neutral:

Start pressure- 99.48

End pressure- 104.1

Base:

Start pressure- 99.89

End pressure- 106.73

The base got the highest pressure but only by .53.

Conservation of Mass Lab Investigation

Can we make a chemical reaction?

Yes!

Hypothesis: If we mix pop rocks and soda, then the pop rocks will add carbonation to the soda and make it fizz. I think that the pop rocks and soda will have a similar reaction to vinegar and baking soda.

Was the hypothesis correct?

No!

Why?

The first test we preformed was the pop rocks and soda test. When the pop rocks were added to the soda they fizzed, but only a little. And the pop rocks did not create more carbonation in the soda. They mostly created a gas. This is why we placed a balloon over the top of the bottle. The second test was preformed the same way but instead we used baking soda and vinegar. When we put the balloon over these they created a large amount of gas. So far it sounds like the two reactions are quite similar, but they are not. The gases they released were created in different ways. The gas from the soda was not created by a chemical reaction but a physical one. The pop rocks and soda contained the CO2 gas that was released when the soda and pop rocks met. But when the second test was preformed a chemical reaction occurred, vinegar + CaHCO3 -> CO2. They created the same gas but in a different way.

Problems:

LAB TEST ONE:

When we were putting the balloon on the soda it got a hole in it. We thought we could fix the problem by plugging it with our finger, but we couldn't. So all of our gas escaped, and our balloon did not blow up like it was supposed to.

LAB TEST TWO:

There really were no problems with the second test. One problem that may be able to be classified as a problem is that when we removed the ballon from the bottle it looked like not all of the baking soda had made it into the vinegar. When we finished the test we poured the vinegar back into the graduated cylinder to see if there was more, less, or the same amount. To us it looked like there was more but that could have been because of the gas that hadn't been released already.

Investigation: Chemical Reactions & Temperature Lab

Does temperature effect chemical reactions?

Yes!

But how do we know this?

Our investigation into temperatures and chemical reactions...

Hypothesis: If we do 3 test, ice water, water at room temperature, and hot water, to see if temperature really does effect chemical reactions, then the hot water will take the least amount of time.

We did all three experiments using alka-seltzer tablets and water, the only variable that changed was the temperature of each experiment .

TEST ONE:

Test one was preformed using 266 mL of hot water. We heated the water, in a beaker, on a hot plate until the water reached the temperature of 50˚ Celsius. The we removed the beaker from the hot plate. We dropped the alka-seltzer tablet into the water and timed how long the chemical reaction lasted. The reaction lasted about 21 seconds.

TEST TWO:

Test two was done using 266 mL of water that was at room temperature. This reaction took longer. It took about 36 seconds. The temperature of the water for this test was 23.4˚ Celsius.

TEST THREE:

In test three we added ice to 133 mL of water, instead of the 266 mL used in the other two tests. In this test the reaction lasted for about 1 minute and 58 seconds. The temperature was 1.9˚ Celsius in the beginning and by the end it had dropped down to .3˚ Celsius.

OBSERVATIONS:

In the first test the alka-seltzer did not sink; in the second test the alka-seltzer bounced around from the surface of the water to the bottom of the water and back up, and in the third test the alka-seltzer sank and did not rise back up to the surface until it was almost fully dissolved.

The fact that the colder the water the longer the reaction, or the slower the reaction, and the hotter water had a faster reaction proves that temperature does in fact play a role in chemical reactions.

The video to this is on my website, it is labeled Investigation Lab Video. Enjoy :-)

ChemThink: Chemical Reactions

CHEMICAL REACTIONS TUTORIAL QUESTIONS:

1. Starting materials in a chemical reaction are called reactants.

2. The ending materials in a chemical reaction are called products.

3. The arrow indicates a chemical change has taken place.

4. All reactions have one thing in common: there is a rearrangement of chemical bonds.

5. Chemical reactions always involve breaking old bonds, forming new bonds, or both.

6. In all reactions we still have all of the at the atoms in the end that we had at the start.

7. In every reaction there can never be any missing atoms or new atoms.

8. Chemical reactions only rearrange the bonds in the atoms that are already there.

9. Let’s represent a reaction on paper. For example, hydrogen gas (H2) reacts with oxygen gas (O2) to form water

(H2O):

H2 + O2H2O

If we use only the atoms shown, we’d have 2 atoms of H and 2 atoms of O as reactants. This would make 1 molecule of H2O, but we’d have 1 atom of O leftover. However, this reaction only makes H2O.

Remember: reactions are not limited to 1 molecule each of reactants. We can use as many as we need to balance the chemical equation.

A balanced chemical reaction shows:

a) What atoms are present before (in the reactants) and after (in the products)

All

b) How many of each reactant and product is present before and after.

The same number.

10. So to make

H2O from oxygen gas and hydrogen gas, the balanced equation would be:

2 H2 + 1 O2  2 H2O

Which is the same as:

# of atoms in Reactants Element # of atoms in Products

4 H 2

2 O 1

11. This idea is called the Law of the Conversation of Mass

12. There must be the same reactants and the same number of atoms before the reaction (in the reactants) and after the reaction (in the products).

13. What is the balanced equation for this reaction? 1 Cu + 7 O2  1 CuO14.

In the unbalanced equation there are:

Reactants  Products

Cu atoms 1 Cu atoms 1

O atoms 14 O atoms 14

15. To balance this equation, we have to add ______ molecules to the products, because this reaction doesn’t make lone _____ atoms.

16. When we added a molecule of CuO, now the number of _____ atoms is balanced but the number of ____ atoms don’t match. Now we have to add more _____ atoms to the reactants.

17. The balanced equation for this reaction is

2 Cu + 1 O2  2 CuO

This is the same thing as saying:

Reactants  Products

# Cu atoms 2 = # Cu atoms 2

# O atoms 2 = # O atoms 2

18. What is the balanced equation for this reaction? (Use the table to keep track of the atoms on each side.) 1 CH4 + 2 O2  2 H2O + 1 CO2

19. What is the balanced equation for this reaction? (Use the table to keep track of the atoms on each side.) 1 N2 + 3 H2  2 NH3

# of atoms in Reactants

20. What is the balanced equation for this reaction? (Use the table to keep track of the atoms on each side.) 2 KClO3  2 KCl + 3 O2

21. What is the balanced equation for this reaction? (Use the table to keep track of the atoms on each side.) 4 Al + 3 O2  2 Al2O3

SUMMARY:

Chemical reactions always involve breaking bonds, making bonds, or both.

The Law of Conservation of Mass says that the same atoms must be present before and after the reaction.

To balance a chemical equation, you change the coefficients in front of each substance until there are the same number of each type of each atom in both reactants and products.

Polymer Lab Group Investigations

Our first lab was creating a plastic using styrofoam, acetone (we used nail polish remover), and food coloring. The experiment started off great! The styrofoam was dissolving in the acetone like it was supposed to, but it started to take a while for the pieces to dissolve. So we decided to start our next experiment, but we kept an eye on the first and sometimes one of us would work on it while the other worked on the second experiment. This experiment was our first attempt at creating a bouncy ball. The ingredients were like the fi

rst experiment we did with creating a polymer, that test was 8 days ago, the only thing that changed was we added cornstarch.

Now to go more in depth:
Bouncy Ball: Can we create a bouncy ball?
Hypothesis: If we add cornstarch to a lab we have already preformed, the What is a Polymer Lab, then the ball will be bouncier then the first. We think that the cornstarch will act as a tighter bonding agent. The borax will first bond the monomers, then the cornstarch will act like a strengthener to the borax. Making the bond between the monomers stronger and tighter giving more of a bounce.

Observations and other: For this test when we were mixing the

"Borax solution with the glue and cornstarch we added the food coloring, instead of adding it straight to the "Borax solution". We also, did not let the mixture of borax solution, glue, and corn starch

sit for 10-15 seconds like the procedures said we were supposed to. This could of had a great on our first attempt to create a bouncy ball and why it was such a failure. Not only did this test not bounce but it also didn't even look like a ball.

Our second test went a little better. Borax was accidentally added into the glue without, when borax solution should have been added. We got most of it out, but I think that might have been the reason test two didn't bounce. Once we got most of the borax out of the glue we added the borax solution. When the mixture was mixed and molded we tried bouncing it. It didn't bounce. But it did mold easier and hold it shape better then the first attempt. (Attempt one on top-Attempt two on bottom)

Making plastic: Can we make plastic?

Hypothesis: We’re using nail polish remover which is diluted acetone, so we’re hoping that the Styrofoam will still dissolve. However, we’re afraid that it won’t, and that we can’t let the rest of the liquid evaporate out of the nail polish remover and leave more concentrated acetone behind because we’ve found from our research that acetone evaporates fairly quickly. To be honest, we think the Styrofoam (even if we break it up into tiny, little balls) will just float around at the top. * sigh * However, if it works, we don’t want to wait 12 hours for it to harden, so we’ve found that chilling a polymer makes it more brittle, and because brittle things are not malleable, we think that by chilling it (and risking shattering) that it will harden faster.

Observations and other:

In the beginning the styrofoam melted in the acetone. Throughout the whole experiment more styrofoam was added when some/most of the styrofoam already in it was melted. The plastic didn't harden and we are not sure of the out come yet. We are letting the experiment sit overnight and will check in on it tomorrow. I will write about what happened (if anything happens) when we see it tomorrow and I get the chance.

Sodium Silicate Lab

Can we form a sodium silicate polymer?

If the two liquids, sodium silicate solution and ethyl alcohol, are combined, then they will form form a solid polymer that bounces higher than the polyvinyl acetate polymer we formed two days ago.

The polyvinyl acetate polymer was made when glue and a solution formed of borax and water was added.

These polymers were both smooth, but the polyvinyl acetate was softer. It was easier to mold, but would change it's shape back, close to it's original form. However, the sodium silicate polymer was harder to mold, it was crumbly and did not like to be shaped, but it would hold the form that it was given. Unlike the polyvinyl acetate it did not adhere to itself easily, the polyvinyl acetate would willingly stick to itself when the sodium silicate had to be pressed into itself to stick there. The silicon ball bounced higher than the polyvinyl acetate.

Both plastics and this silicon polymer are hard and smooth. Just like plastic this silicon polymer would stay in shape unless forced to take on a different shape. Like when you step on a plastic depending on how hard it is it might crumple under the force your foot is using to press it down, this happened in a similar way when we used our hands to mold the silicon and force it into shape.

When the two liquids were mixed, the mixture became first became cloudy and then as we started to mix them together they quickly hardened and became clumps. Then when we pressed it a liquid came out of the ball. I think that it might have been the ethyl alcohol because it was thin and clear, unlike the sodium silicate solution that was thicker and a little cloudy. Our ball seemed to be grayer then those of the other groups in the class. This could simply be because something that it touched was dirty, like the table or our hands.

We had a couple of problems such as when we went back to the fridge to get our ball someone had taken it, so we decided to do tests with the new ball. Once we were finished our first ball was found and we had to wait another 10 minutes while the ball cooled in the fridge and them had to preform the second test all over again.