Yeast Beasts in Action

Results:

When hydrogen peroxide was added to each solution, it seemed a little lighter. This was because the hydrogen peroxide was a clear substance.

When we put the yeast in the water, it spread out on the top. It didn't really mix in very well until we stirred it. After it was stirred, the mixture was a cloudy tan that had clumps of gooey yeast in it.

All of our mixtures had a starting kPa of 96.88.

The acid solution was soda, and had the greatest activity, because the gas pressure rose the quickest and went the highest. The ending kPa was 104.7. The reaction caused a lot of bubbles to rise to the surface of the solution.

The neutral solution was milk, and actually had the least activity. This makes sense, though it contradicts our hypothesis, because neutral things tend to not get involve

d. It ended with a kPa of 99.7. The reaction produced a thin, foamy layer on top of the milk.

The base solution was antacid. Its reaction occurred faster and had larger kPa than that of the neutral solution, but slower than that of the acid. The reaction created a thick, foamy layer of bubbles above the solution. The ending kPa was 101.79.

Conclusions:

Hypothesis: The acid will produce a stronger reaction that happens quicker than the others. The base reaction will be the slowest and least powerful. The neutral reaction will be between the other two.

We rejected our hypothesis. This was because the neutral reaction had less gas pressure than the base reaction. We were quite surprised by this, but after some thought, we came to the conclusion that it was probably because neutral substances have less to react with. From this experiment, we concluded that acids released the most gas pressure because they have a corrosive nature. The yeast was thus dissolved faster and more thoroughly, releasing more gas. I think the reason we used hydrogen peroxide was because it helped to thin the solutions, and it is a weak acid. From this experiment, we learned that sometimes, comparing data to information on parts of the experiment or to things in real life can help conclusions be made. For instance, my group decided that the neutral substance was the least reactive because neutral items, countries, substances, etc. tend to not get involved/have an effect on a situation. My group encountered no errors. We had a quick, successful experiment.

Conservation of Mass Lab Investigation

Results:

Pop rocks:

Prediction: Won't inflate very much, just enough to fill it with the balloon.

The balloon inflated with CO2 (which we knew because the package says that it is processed with CO2, and we learned that this happens by injecting the pop rock solution with CO2 bubbles and letting them harden in it). The balloon inflated more than I expected, making it about the size of a baseball.

I think that different groups got different sized balloons depending on how compacted their Pop Rocks were, and on whether or not they had stretched their balloons beforehand.

This was not a chemical reaction, because it was just the Pop Rocks being dissolved and the bubbles released.

Vinegar:

This balloon inflated to the size of a small watermelon. The reaction occurred faster than before and released a lot more gas. The reaction also began instantly, the moment we put the baking soda in vinegar. We measured the amount of vinegar after the reaction, and found that there was more. However, there were still quite a lot of bubbles in the vinegar, and this may have accounted for the seemingly extra vinegar because it was extra mass.

Conclusion:

I accepted my hypothesis. This was because the mass didn't change but the gas was released. In this lab, I learned that gathering as much information as possible beforehand helps to lead to more accurate conclusions. This is because I read the lab sheet information and the back of the Pop Rocks package. My group had no problems. In fact, our lab was quite easy and went smoothly. It was a great and easy way to learn about conservation of mass.

Chemical Reactions & Heat Lab

Hypothesis

The hot temperatures will cause a fast reaction, the room temperature will cause a reaction slower than the hot temperature, but faster than the cold temperature, and the cold temperatures will cause a very slow reaction.


Results/Observations

Hot Water Test:

The water was at 24.5ºC before the test.

We heated the water to 50ºC.

We couldn't get the tongs in time to remove the beaker from heat when the water was at exactly 50ºC, so whe

n we finally removed it, the water was 55ºC.

We waited for the water to cool to 50ºC before we dropped in the tablet.

There was an inst

ant visible reaction.

The tablet dissolved in 22.4 seconds, causing the water to fizz and bubble.

After the tablet dissolved, the water was 48.9ºC.

Room Temperature Water Test:

The water started at 25.3ºC.

The reaction was slower than before, but still extremely fast.

The reaction took 36.4 seconds, and the end temperature for the water was 24.9ºC.

Cold Water Test:

We put about 6 ice cubes in the water, and stirred for 60 seconds.

The water lowered to exactly 1ºC. When we dropped the tablet in, the reaction took place extremely slowly. The temperature rose to 1.4ºC, then dropped to 1.3ºC by the end of the reaction.

The reaction took 2 minutes 8 seconds.

Conclusion

My hypothesis was correct, and I accepted it completely. My hypothesis worked because the hot water caused the reaction to finish far faster than the reaction for the cold water. The part of the hypothesis referring to the room temperature was correct, too, because it was faster than the cold temperature but slower than that of the hot temperature. I learned that it is very important to read directions carefully and thoroughly because of one problem we ran into. The problem was that we took the probe out to let the alka-seltzer dissolve in the hot water test. We didn't realize it until the moment we finished the hot water test, and then we put the probe in the water to get that temperature. This could definitely skew results based off of the temperatures.

ChemThink; Chemical Reactions

1. Reactants
2. Products
3. Chemical Change
4. Rearrangement
5. Breaking; forming
6. Atoms
7. Missing; new atoms
8. Rearrange the bonds
9. 2 atoms of H; 2 atoms of O; 1 molecule of H2O; 1 atom of O
10. 2 atoms of H2; 1 atom of O2 ; 2 molecules H2O

# of atoms in Reactants; Element; # of atoms in Products
4; H; 4
2; O; 2

11. Law of Conservation of Mass

12. mass; atoms

13. 2 Cu; 1 O2; 2 CuO

14. Reactants: Cu atoms, 1; O atoms, 2

Products: Cu atoms, 1; O atoms, 1

15. one CuO; oxygen

16. O; Cu; Cu

17. 2 Cu; 1 O2; 2CuO

#Cu atoms 2= #Cu atoms 2

# O atoms 2= # O atoms 2

18. 1 molecule CH4; 2 molecules O2; 2 molecules H2O; 1 molecule CO2

19. 1 molecule N2; 3 molecules H2; 2 molecules NH3

20. 2 molecules KClO3; 2 molecules KCl; 3 molecules O2

21. 2 atoms Al; 3 molecules O2; 2 molecules Al2O3

Summary:

1) breaking chemical bonds; forming new ones; or both.

2) present before and after the reaction.

3) coefficients; atoms

Polymer Lab Group Investigation

State the Problem:
Will adding extra borax or using less affect the rebound of the polymer?

Hypothesis:
One teaspoon of borax will leave the glue somewhat sticky and unformed. Adding extra borax will make no difference because the water will be saturated.

Materials:

40 mL white glue (polyvinyl acetate)
525 mL water
1 stirring rod
1 500 mL beaker (we used a 600 mL beaker)
1 200 mL beaker (we used a 250 mL beaker)
1 graduated cylinder
4 tsp. borax (hydrated sodium borate)

Procedures:

Begin by gathering the necessary materials. Measure 400 mL of water into the large beaker. Be very exact when measuring. Add one teaspoon of borax to the liquid and stir until the water is saturated and the most of the powder has dissolved. Set this beaker aside. Place 40 mL of glue into the small beaker. Next, slowly and carefully measure 25 mL of the borax solution into the graduated cylinder. Pour this part of the solution into the glue while a lab partner stirs continuously. If the solution is not stirred continuously, the experiment may not be as successful. Stop stirring when most of the water has been absorbed into the glue.

Test the rebound of the polymer. Drop it from 30 cm five times and record the average rebound height.

Repeat the process with a new polymer, but the same beaker of borax solution. Add three more teaspoons of borax into it, for a total of four teaspoons. Conduct the same tests.

Results/Observations:
The first polymer was very sticky. It left a lot of extra solution in the beaker, and it didn't bounce well. It's rebound was 7 cm. One thing we noticed was that as it dried, it became a little less sticky.

The second polymer was a mess at first. It was really tight and hard in some spots, and still plain glue in others. After we placed it in the solution again, it became far more evenly solidified, and worked very well. However, this one also left a lot of extra solution in its beaker. It had a rebound of 11.6 cm when we tested it.

Conclusions:

I accepted my the first part of my hypothesis, because the polymer did just that: it was a sticky mess. However, I rejected the second part of my hypothesis, because the second polymer was actually a little bit slimy/squishier than the polymer from the class lab we did using these materials. The extra borax didn't dissolve into the water because it was saturated, and I think it made a difference because there was a lot of borax floating in the water. There were a lot of problems with our lab. For instance, we started by quickly rewriting our lab because we couldn't get the milk we needed for our original lab from the school. Another problem was being slowed down by the low glue supply. We went through six bottles to get enough glue for both polymers, because there was so little left in each bottle! We also were a little bit anxious to test the polymers, and we had to return them to the solution after we pulled them out because they hadn't been in long enough. This really messed us up, and I've learned to be very patient in labs, because the results can often depend on it. I've also learned that sometimes plans need to be changed, so I should always have a backup plan and be flexible.

Sodium Silicate Polymer Lab

State the Problem:
What is a sodium silicate polymer?

Hypothesis:
The polymer will become a hard, translucent, bouncy ball.

Results/Observations:
The sodium silicate was syrupy as it was being poured into the beaker.
When we poured the alcohol into the sodium silicate, there was an immediate reaction. That portion of the mixture became slightly cloudy and thicker. When we began to stir it, the surface became like a thin layer of rubber, stretchy and breaking as too much tension was put on it. The mixture became jelly-like for a moment, then soon became somewhat granulated in texture. Eventually, the stirring made the mixture become a clump of wet, grayish-clear granules. I removed the clump from the beaker and started to compress it. I noticed that the ball dripped extra liquid, which helped it to solidify. As it dried/solidified, it became stickier and smoother. It was actually fairly difficult to compress, as it was much tougher than the polymer we created on Tuesday. Finally, we had a sphere of white-gray polymer. We conducted the rebound test on it, meaning we dropped it 5 different times from 30 cm, and the average height was 19.2 cm. However, when we cooled it for about 15 minutes and conduced the same test, its average was only 17.6 cm. It also felt heavier and harder after being cooled.

Questions:
What characteristics are similar between your two types of polymers you have made? Differences?
-Similarities I spotted between the two polymers are that they were both fairly bouncy, whitish, and moldable. However, one was stretchy while the second was firmer, and the chemical reaction was faster the second time than the first.

Most commercial polymers are carbon based. What similar properties do silicon and carbon share that may contribute to their abilities to polymerize?
-They both can give up or take in 4 electrons, which gives them an incredible ability to bond.

Plastics are made of organic (carbon based) polymers. What similarity does the the silicone polymer share with the plastics?
-I actually had a very difficult time finding this answer....I can really only find differences. I suppose one similarity would be their formation because of the ability to bond easily.

How did you know that a chemical reaction had taken place when the when the two liquids were mixed?
-The reaction could be seen instantly when the sodium silicate turned cloudy in response to the ethyl alcohol being added. It also changed textures/consistency as I stirred.

How could you find out what liquid was pressed out of the mass of crumbled solid as you formed the ball?
-You could use certain chemicals and procedures to separate certain "ingredients" in the liquid, much like the way we isolated the DNA of a strawberry in a previous lab.

Compare your ball with those of the other members of class. How many properties can you compare?
-My group had an average rebound of 19.2 cm, whereas Brad and Luke had a 20 cm average. When we chilled ours, we had a 17.6 cm average, and Brad and Luke still had a 20 cm average. Their polymer was definitely larger than ours, and in the words of Jackson, theirs was more "chunky and lumpy." However, ours bounced higher when we compared them later. Our ball was also more translucent.


Conclusions:

I accepted my hypothesis, because it was actually almost perfect. When we molded the polymer, it formed a tough, semi-translucent ball with a high rebound. I really enjoyed watching the chemical reaction. I've said it before, but I really love this kind of science. I've learned that sometimes you'll work with dangerous chemicals and you have to be very cautious and completely follow directions. For instance, I was very careful not to touch the sodium silicate. I was curious as to what would happen if I did, but the instructions clearly stated not to touch it. This helps success to come about in labs. The lab was actually fairly easy, and my group didn't come across any problems.