Acid and Base Yeast Lab

In the acid base lab, my partner and I had hypothesized that the acid would create the best reaction because in our elephant toothpaste lab, the hydrogen peroxide had produced a large reaction with the hydrogen peroxide, which had a pH level of 2.6. We had assumed that if the lower pH of the hydrogen peroxide had caused a reaction, so would the low pH of the diet cola, which had a pH of 2.9. However, we had been proved greatly wrong. Our results are available below:

The green was the antacid (base), the blue was the skim milk (neutral), and the cola was red (acid). The acid had the greatest initial rise, but the slope soon lowered. All of the tested materials didn't have a steady rise, they all had steep slopes and some more level slopes. Our hypothesis had been proved wrong  right after we had conducted our first test and found that the neutral skim milk had produced more gas than the acid. At the end of all the tests, all of the pressure levels were on the rise, but we had to keep the time as a constant (and the lab wouldn't let us go longer), so we stopped at 2 minutes. Our group had noticed differing pressures and results from other groups. For example, one group had acid as the highest with a pressure of 140, but upon closer investigation, we discovered that the groups who we noticed differences with had added more hydrogen peroxide or more yeast than necessary. 

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 atoms at 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 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)

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:

2H2 + 2O2 → 2 H2O Which is the same as:

4 H atoms in the reactants

4 H atoms in the products

2 O atoms in the reactants

2 O atoms in the products

11. This idea is called the: Law of 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 + 1 O2 → 2 CuO

14. on the unbalanced equation there are: Reactants: Cu atoms 1/O atoms 2 → Products: Cu atoms 1/O atoms 2

15. To balance this equation, we have to add 2 molecules to the products, because this reaction doesn’t make lone oxygen atoms.

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

17. The balanced equation for this reaction is  2Cu + O2= 2CuO

This is the same thing as saying:

2 Cu atoms in the reactants

2 Cu atoms in the products

2 O atoms in the reactants

2 O atoms in the products

20. 2 KCIO3  +  2 KCI →  3 O2 21. 4Al  + 3O2  →  2Al2O3

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.) 1N2+ 3H2 →  2NH3

20. What is the balanced equation for this reaction? (Use the table to keep track of the atoms on each side.) 2 KCIO3  →  3O2+  2 KCI

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

SUMMARY

1. Chemical reactions always involve breaking bonds.
2. The Law of Conservation of Mass says that the same atoms must be present before and after the reaction.
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.

Polymer Lab Group Investigation

Joey and I set out to find if adding or subtracting glue to the original polymer we made last Tuesday would change the physical properties of the polymer. We started out like the normal ab, but we poured glue into two beakers instead of one. One beaker had 20mL and the other had 60mL. We added the same amount of borax to each of the beakers. When we mixed the glue and the borax, the beaker with the larger amount of glue mixed throughout, but the beaker with the smaller amount still had borax left in it.

Joey and I had concluded that the monomers in the glue bound to the maximum number of monomers in the borax, and the polymer formed had become fully saturated and could no longer absorb any of the borax. The extra glue polymer was more easily moldable and it resembled more of a dough or a clay, while the other one was more filmy and harder to mold. We found that the bounce of the polymer that had more glue was 2.7cm higher than the original polymer made last Tuesday. We also refrigerated the polymer, and just as it had on Friday, the bounce went up by .5cm. However, one thing that was different about the extra glue polymer was that it became misshapen in the fridge; our guess was that the extra glue had made the polymer more of a liquid than it previously was. Due to the misshaping in the fridge, it bounced all over the place during our second rebound test.

Sodium Silicate Polymer Lab

In the Sodium Silicate lab, we crated a polymer by combining Sodium Silicate (Na2Si3O7in H2O) with Ethyl to create a polymer. This occurred when two oxygen atoms of silicate are replaced by ethyl with loss of water. The sodium silicate polymer had some very different attributes than the polymer formed with polyvinyl acetate. Both were white, but the sodium silicate polymer was more of a hazy, crystalline structure than the putty-like, solid white polymer previously formed. The polymer that was formed more recently (although very crumbly at first,) was firmer and had more rebound than the one formed on tuesday. The polymer formed on tuesday had an increase in rebound after being chilled, today's had less of a rebound. I think that this is because today's was more brittle from the beginning, while yesterday's had been more squishy initially, so when it chilled, it became only slightly hard and actually did something for the polymer's rebound (as compared to today, when it just made it even more hard, lessening the rebound.) Another difference between the two polymers is the firmness of the polymers. The first one made was easily molded and sculpted, but with the more recent one, you had to apply a considerable amount of pressure to make an indent if it was molded properly. One thing that the silicon and the carbon is that they both have four chemical bonds available. You could tell a chemical reaction occurred because the matter changed states from a solid to a moldable solid

The Science of Addiction

How the Brain Sends Signals
Neurons are the cells responsible for passing chemical and electrical signals along the pathways of the brain. Information from one neuron flows to another neuron across a small gap called a synapse. At the synapse, electrical signals are translated into chemical signals in order to cross the gap. Once on the other side, the signal becomes electrical again.
Brain Imaging Technologies
Two major types of brain imaging technologies are MRI (Magnetic Resonance Imaging) and PET (Positron Emission Tomography) scans. In this next section, I will explain the process for each of these technologies
Magnetic Resonance Imaging- MRI's detect changes in blood flow. When an area in the brain experiences increased activity, there is a rush of blood to that area to replenish the oxygen used by the brain cells. By tracking variations in blood flow, MRI can detect active sites in the brain. An MRI machine has a magnetic field that is useful because certain atoms resonate waves of energy when surrounded by magnets. In an MRI, the energy pulse detected is a radio wave, rather than the gamma waves that PET scanners use.
Positron Emission Tomography- Positron Emission tomography scans, or PET scans measure energy that is emitted when positrons from the radioactive material given to the patient prior the scan, collides with the electrons in the person's brain. The scan takes between half an hour and two hours to be fully completed.
Drugs and the Brain
Drugs cause major changes to synapses in the brain. They bypass the five senses and directly activate the brain's reward circuitry. Drug abuse affects the brain, to the point where the brain must adapt. One way the brain compensates is to reduce the number of dopamine receptors. As a result, after the drug abuser has come off their high from whatever drug they abused, they will need more of the drug next time they want to get high. As the brain continually adapts to the drug, other regions are affected. Brain regions responsible for judgment, learning and memory begin to physically change. Once this happens, drug-seeking behavior becomes driven by habit, almost reflex. This is how a drug user becomes transformed into one of those people you see on the meth commercials who steal from their parents.

 How Drugs Kill
Most drug overdose cases involve the use of more than one drug, also called a polydrug cocktail.
 Heroin- Heroin causes the most drug related deaths than any other drug. The majority of these deaths are caused by respiratory failure.
Alcohol-Alcohol overdoses normally occur in two ways. In the first way, alcohol causes unconsciousness by decreasing the effect of glutamate; it can also cause breathing to slow or cease. In the second, the body tries to rid itself of alcohol that has not been absorbed by vomiting.
Nicotine-Simply smoking CAN NOT lead to a nicotine overdose, but it is possible to overdose on nicotine by using combinations of products that directly provide the body with nicotine (nicotine patches, nicotine gum, etc.). Sometimes, nicotine can reach levels high enough to paralyze muscles that control breathing or cause a heart attack.
Cocaine- Cocaine can kill in a variety of ways, but the most common are heart attack, hyperthermia, and brain damage. Taking even a low dose of cocaine multiplies your chances of having a heart attack by 24!
Amphetamine, Methamphetamine, and MDMA (Ecstasy)- amphetamines increase levels of dopamine and norepinephrine. Overdose normally occur in the form of a heart attack, overheating, or brain damage.