During the Yeast Beasts in Action Lab investigation I did not know what to expect. We were trying to figure out the highest pressure change that occurred in the test tubes once the yeast was added. We used diet soda as the acid, skim milk as the neutral and antacid as the base. The combination is 3mL of hydrogen peroxide, 3mL of the mixture and two drops of yeast. There was never a noticeable physical change in the combination after being shaken, but the pressure did rise. My hypothesis was right, but I was surprised. I thought that if the yeast was added to the mixture then the mixtures pressure would rise. I was right, but I thought that the acid’s pressure would have gone way beyond the bases pressure. But it was a real close tie between all of them. I did expect the neutral mixture to lack in pressure. The acid had the highest pressure at 101.71 pKa, while the neutral mixture had the lowest at 99.36 pKa. The bases pressure was at 101.35 pKa. The reason that acid had the highest pressure is became yeasts are microorganisms. They break down the hydrogen peroxide into oxygen gas and water. Acids produce more oxygen gas then neutral and base mixtures. The oxygen gas causes the pressure. I conclude that acid produce more pressure than bases and neutrals. Some problems that may have occurred might have been caused by distraction and miss measurements.
Wednesday, March 23, 2011
Thursday, March 17, 2011
Sodium Silicate Investigation
In this lab experiment we tested the conservation of mass. We did this using Pop Rocks (the candy), a full bottle of soda, two balloons, vinegar and baking soda. My hypothesis was proven to be correct. I had predicted that both of the experience would expand the balloon with air to point of which it was full. But not to the point of which it would not be able to hold it and break. The combination of Pop Rocks and carbonated liquid resulted carbon being releases and expanding the balloon. This reaction occurred because Pop Rocks are carbonated candy. When they melt the 600 PSI bubbles of gas are released. We did have to speed the process along by shaking the soda bottle. This probably increased the speed of the reaction because more carbon from the soda was released. The vinegar and baking soda turned out to be reactants in a chemical reaction. What happened was the acetic acid combined with the sodium bicarbonate created carbonic acid. It's categorized as a double replacement action. This test made the balloon expand even more than the Pop Rocks did. The first attempt was a fail because the balloon was releasing air. If we had stretchier balloons I feel the experiment would have gone better. Also, the balloons were incapable of holding the entire packet of Pop Rocks! Another variable that differed between groups is the type of soda each team used.
Tuesday, March 15, 2011
Chemical Reactions and Temperature Lab Investigation
In this experiment we were testing how temperature effects chemical reactions. My hypothesis was correct, if the temperature was higher then the reaction would occur quicker than it would if the temperature was cooler. The variables tested were room temperature water, chilled water and heated water.
The room temperature was 74.8 Fahrenheit. When the Alkine seltzer tablet was introduced to the water it fizzed immediately. As it grew smaller it rose to the top, I feel this had no relevance, but after thirty-six seconds the reaction concluded. The only peices of the tablet that was left were flakes that remained at the surface of the water. The water temperature dropped .7 degrees Fahrenheit.
The chilled water was just 133mL of water with three ice cubes. The temperature was at 58 degrees Fahrenheit. The tablet took one minute and eleven seconds to dissolve. The temperature was then had risen .2 degrees Fahrenheit. It had completely dissolved the water was clear.
The heated water was at fifty degrees celsius. The tablet dissolved very fast. It only took 21.1 seconds. The water was full of tiny, little bubbles. The temperature had dropped .3 degrees Celsius.
For a chemical reaction to take place the reactants have to make physical contact with each other. I conclude that heat controls the frequency of these encounters. Meaning it also has control of the rate that the products are formed at. By increasing the heat, the rate of the chemical reaction is also increased. A chemical reaction at a higher temperature delivers more energy into the reactants and increases the reaction rate by causing more collisions between particles. I do not believe any mistakes were made that could have changed the results.
Friday, March 11, 2011
Chem Think; Chemical Reactions
Liora Fiksel
BULGRIN Integrated Physical Science
a) Go to www.chemthink.com. Log in using your user name and password. (If you forgot, you need to WAIT
QUIETLY until your teacher is done introducing the lesson)
b) Scroll to C H E M I C A L R E A C T I O NS then the tutorial under the Chemical Reactions menu.
c) Complete the tutorial. As you complete the tutorial, write down the answers to the questions below.
d) Once you have successfully completed the tutorial and this worksheet, complete the Q uestion Set.
C H E M I C A L R E A C T I O NS T U T O R I A L Q U EST I O NS :
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 rearragngement of bonds.
5. Chemical reactions always involve breaking bonds, forming bonds, or both.
6. In all reactions we still have all of the same atoms at the end that we had at the start.
7. In every reaction there can never be any atoms or new atoms missing when the reaction is over.
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 3 of atoms of O as reactants. This would make water 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 balancethe chemical equation.
A balanced chemical reaction shows:
a) What atoms are present before (in the reactants) and after (in the products)
b) How many of each reactant and product is present before and after.
10. So to make H2O from oxygen gas and hydrogen gas, the balanced equation would be:
__2__ H2+___O2=__2__H2O
Which is the same as:
11. This idea is called the conservation of mass.
12. There must be the same mass 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?
__2__ Cu + _____ O2 __2__ CuO
14. In the unbalanced equation there are:
Reactants
Cu atoms _2____
O atoms _2____
Products
Cu atoms __2____
O atoms __2____
15. To balance this equation, we have to add _2_ molecules to the products, because this reaction doesn’t make
lone __2___ atoms.
16. When we added a molecule of CuO, now the number of __CU___ atoms is balanced but the number of _Oxygen___ atoms don’t match. Now we have to add more __CU___ atoms to the reactants.
17. The balanced equation for this reaction is
Cu+O2=2 CuO
This is the same thing as saying:
Reactants
# 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.)
CH4+2O2=2H2O+CO2
19. What is the balanced equation for this reaction? (Use the table to keep track of the atoms on each side.)
N2+3 H2=2 NH3
20. What is the balanced equation for this reaction? (Use the table to keep track of the atoms on each side.)
2 KCIO3= 2 KCI+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
SU M M A R Y
1) Chemical reactions always involve breaking bonds, forming bonds, or both.
2) The Law of Conservation of Mass says that the same atoms must be in the reactants and in the products.
3)To balance a chemical equation, you change the coefficients in front of each substance until there are the same number of each type of atom in both reactants and products
BULGRIN Integrated Physical Science
a) Go to www.chemthink.com. Log in using your user name and password. (If you forgot, you need to WAIT
QUIETLY until your teacher is done introducing the lesson)
b) Scroll to C H E M I C A L R E A C T I O NS then the tutorial under the Chemical Reactions menu.
c) Complete the tutorial. As you complete the tutorial, write down the answers to the questions below.
d) Once you have successfully completed the tutorial and this worksheet, complete the Q uestion Set.
C H E M I C A L R E A C T I O NS T U T O R I A L Q U EST I O NS :
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 rearragngement of bonds.
5. Chemical reactions always involve breaking bonds, forming bonds, or both.
6. In all reactions we still have all of the same atoms at the end that we had at the start.
7. In every reaction there can never be any atoms or new atoms missing when the reaction is over.
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 3 of atoms of O as reactants. This would make water 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 balancethe chemical equation.
A balanced chemical reaction shows:
a) What atoms are present before (in the reactants) and after (in the products)
b) How many of each reactant and product is present before and after.
10. So to make H2O from oxygen gas and hydrogen gas, the balanced equation would be:
__2__ H2+___O2=__2__H2O
Which is the same as:
| # of atoms in reactants | elements | # of atoms in products |
| 4 | H | 4 |
| 2 | O | 2 |
11. This idea is called the conservation of mass.
12. There must be the same mass 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?
__2__ Cu + _____ O2 __2__ CuO
14. In the unbalanced equation there are:
Reactants
Cu atoms _2____
O atoms _2____
Products
Cu atoms __2____
O atoms __2____
15. To balance this equation, we have to add _2_ molecules to the products, because this reaction doesn’t make
lone __2___ atoms.
16. When we added a molecule of CuO, now the number of __CU___ atoms is balanced but the number of _Oxygen___ atoms don’t match. Now we have to add more __CU___ atoms to the reactants.
17. The balanced equation for this reaction is
Cu+O2=2 CuO
This is the same thing as saying:
Reactants
# 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.)
CH4+2O2=2H2O+CO2
| # of atoms in reactants | Element | #of atoms in Products |
| 1 | C | 1 |
| 4 | H | 2 |
| 2 | O | 3 |
19. What is the balanced equation for this reaction? (Use the table to keep track of the atoms on each side.)
N2+3 H2=2 NH3
| # of atoms in reactants | Element | #of atoms in Products |
| 2 | N | 1 |
| 2 | H | 3 |
20. What is the balanced equation for this reaction? (Use the table to keep track of the atoms on each side.)
2 KCIO3= 2 KCI+3 O2
| # of atoms in reactants | Element | # of atoms in prodcts |
| 1 | K | 1 |
| 1 | CI | 1 |
| 3 | O | 2 |
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
| # of atoms in reactants | Element | # of atoms in products |
| 1 | Al | 2 |
| 2 | O | 3 |
SU M M A R Y
1) Chemical reactions always involve breaking bonds, forming bonds, or both.
2) The Law of Conservation of Mass says that the same atoms must be in the reactants and in the products.
3)To balance a chemical equation, you change the coefficients in front of each substance until there are the same number of each type of atom in both reactants and products
Wednesday, March 9, 2011
Glue Polymer Lab Investigation-New variable
This lab investigation did surprise me. I thought if we doubled the borax solution then it would not bounce. I was right, but not for the same reasons. I thought that if more borax was added it would become slimy and liquid-like but it became thick and sticky. What I figured out was that the borax solution was cold, adding it to the glue creates a cold, thick, sticky, flexible and a not bouncy polymer. Six minutes later, when it warmed up to room temperature it was capable of bouncing up to six centimeters! The texture was much duller, or not as sticky. The refrigerated polymer was really sticky, more sticky than when it was first made. Yet it did bounce higher than when it was just made. It bounced 2 cm. A variable that might have changed the results was that we did not have enough time to keep it in the fridge the full amount of time. In the process, when actually combining the components another variable occurred. The polymer became saturated and did not accept the full amount of borax.
Comparing this polymer with the first one with half the amount of borax we can tell that borax is the main component to cause it to bounce. That and the temperature. Polymer #1 had a duller texture, bounced higher, and even higher when refrigerated. That confuses me because when polymer #2 was colder then when it was originally was made, it bounced 2 cm compared to 0 cm. What I thought caused this was the sticky consistency. When it was bounce it stuck to the table, but when it was not as sticky it had a chance to rebound.
Comparing this polymer with the first one with half the amount of borax we can tell that borax is the main component to cause it to bounce. That and the temperature. Polymer #1 had a duller texture, bounced higher, and even higher when refrigerated. That confuses me because when polymer #2 was colder then when it was originally was made, it bounced 2 cm compared to 0 cm. What I thought caused this was the sticky consistency. When it was bounce it stuck to the table, but when it was not as sticky it had a chance to rebound.
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