3 Questions Blog- 5/9/14

1. What tasks have you completed recently?

Recently I have completed my US History and Chemistry end of course exams and other than taking tests or studying for them, I’ve began a section on gas laws and have so far completed notes, flipped questions, and a blog. For culinary arts, I prepared and served desserts to the staff at Mayfield and also in English, we are continuing to read and discuss A Picture of Dorian Gray and have been completing ID novels for the novel.

2. What have you learned recently?

Recently, I have spent time learning about civil rights in my history class and we have learned about gases, gas laws, and how they can be used in my chemistry class. I have learned about Parallelism in my English class and have just finished up our grammar final; in culinary I have been reviewing and studying everything from this semester in order to get a good grade on the last section of our final.

3. What are you planning on doing next?

I am planning on preparing myself for my AP test for US history this coming Thursday and I will also study 100% of my free time so I can get good grades on all my finals. Another thing is staying on top of my homework and overall just focusing on surving my last 2 weeks as a Junior at Mayfield High school. 

Airbags

The first thing you must know is that an airbag is deployed when the car decelerates very quickly, and a crash sensor releases a signal that initiates the inflation of the airbag.When the crash sensor senses the impact, its signal turns on an electrical circuit that ignites a pellet of NaN3, also known as sodium azide. This creates a reaction that produces hot nitrogen gas that fills the airbag. When the driver hits the airbag, though, the airbag has already begun deflating to create a cushion for the driver. Image

The gas laws are involved in different ways. How the airbag is inflated is due to Charles law, which states that volume and temperature are directly proportional when the pressure is constant. T1=The nitrogen gas that fills the airbag is extremely hot from the reaction, causing it to inflate; V1=Since the temperature is very hot the gas expands rapidly as well, filling the airbag; T2=While expanding, the gas cools down significantly from the temperature of the outside air; V2=The volume will decrease, deflating the bag slowly to create a cushion for impact. To solve for the amount of Nitrogen gas after inflation, you must now that when the reaction occurs the heat generated is 300 degrees Celsius or 573 K. Airbags are usually 60.0 L, the volume that the N2 fills into, and the temperature of the N2 returns to 25 degrees Celsius when the gas had fully inflated the airbag, and has begun to deflate. 

(V1)(T2)=(T1)(V2)

(60.0L)(298K)=(V)(573K)

(17880 L K)=(V)(573K)

V=31.20418 L

Airbags are essential in preventing many injuries from car accidents in our society.Airbags are continuously being developed, and perhaps in the future, scientists can create an airbag that will protect us during and after the crashes.

Sources

http://www.chemistry.wustl.edu/~edudev/LabTutorials/Airbags/airbags.html

http://www.lanl.gov/quarterly/q_sum03/airbags.shtml

Class Notes

Water Pressure

Today in class we experimented with water pressure. To begin the lab we had a funnel connected to a long tube that connected to a big jar. The jar was sealed, so there was a limit to how much water we could put in because there was the space was already filled with air. Once we filled the tube with water and no air pockets were left we started to constantly fill up the funnel as it drained. As it was filling up, the air being compressed in the jar became smaller and smaller until it could no longer fit any more water we added. So the water flow stopped once the air was to the point of being completely compressed. We performed this experiment three different times and the only difference was the height of the funnel that led to the jar from the floor: high, medium and low. When we measured the volume of water in the jar we had a total volume of 2,510.0 mL. The final water volume at each of the heights was different because as you adjusted the height of the tube leading from the funnel to the jar, was changed. The tallest height had the most pressure because the water was pouring straight into it, and for the tube at the lowest height became curved and would then have a slower water flow into the jar. In result, for example, when we had our funnel at the highest point which was 172.1 cm there was only 410.0 mL of water that the jar was able to hold because of all the pressure from the gas that was built up in the jar. As you do this lab you have to know the difference between solids, liquids and gases. Solids don’t morph into other shapes unless they are heated; have a structure that makes them much harder than liquids or gases and the molecules in a solid are tightly packed making it unable to change shape or size. Liquids are simply some elements that are liquid at room temperature and they can take the shape of whatever container they are in. Gases can move much faster and are less tightly packed than solids and once heated, they move at a much rapid pace; molecules constantly create collisions between each other.The reason in the experiment that the pressure is changing is because it is being forced into a smaller volume so once the water is being placed inside the jar the molecules from the gas are moving faster. 

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Sources:

Class Experiment

Class Results/ Discussion

Who Cares About Titration?

Titration is an analytical technique in which one can calculate the concentration of a solute in a solution, or in other words a process in which one solution is added to another solution to where it will react under conditions in which the volume can be measured. Titration is usually associated with acid-base reactions but can also involve other types of reactions as well. Why and how can titration be used to determine the concentration of anything. Concentration=molarity; molarity measures concentration. By adding a substance with a known molarity and known volume to something with an unknown molarity and known volume, it is possible to figure out the molarity of the the unknown with the following equation: (M1)(V1) = (M2)(V2).We performed a lab that required us to do exactly that. In order to know how much of the known to add, we put phenolphthalein in the unknown, it turns colorless in acidic solutions and pink in basic solutions.

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Now to determine the concentration of an antacid tablet composed of magnesium bicarbonate you have to use an acid such as Hydrochloric Acid. Now based on my understanding of titration and with help from my online sources, you can follow the steps to titrate Magnesium bicarbonate.

1. Clean, rinse, and fill a buret with HCl solution. Record the molarity of the HCl and the initial HCl volume reading from the buret .

2. Weigh the antacid tablet the and record the mass.

3. Transfer it to a clean 250 mL Erlenmeyer flask.

4. Add distilled water to the flask and swirl the flask to help dissolve the antacid. Make sure to dissolve it completely.

5. Add 3 to 4 drops of phenolphthalein indicator to the flask, and titrate the base solution to a phenolphthalein endpoint. Record the final HCl volume (+0.02 mL).

6. Repeat this analysis on two other brands of antacid tablets.

Sources:

http://www.chem.latech.edu/~deddy/chem104/104Antacid.htm

Lab Results/ Class Notes

Cool Chemical Reactions

This blog is going to be about the article on the 10 most amazing Chemical Reactions. I am going to explain which chemical reaction is an actual chemical reaction and which one is not because not every member of the list is an actual chemical reaction. Then I will provide balanced chemical equations for the actual chemical reactions, including the type of reaction involved which is decomposition, combustion, etc. Finally I will choose my favorite chemical reaction from the author’s list and why I liked it over the others.

1.The chemical reaction beginning at the bottom of the list is a chemical reaction due to a change in color but this doesn’t help when color changes are also present in both chemical and physical changes. We can’t figure out a chemical equation because there weren’t any specific chemicals given.

2. The next reaction going up the list is also a chemical reaction due to its smoke and fire which would cause this chemical reaction to be a single replacement metathesis and is also redox: Fe2O3 + 2Al = Al2O3 + 2Fe

3. This reaction which includes superfluid helium isn’t a chemical reaction, because phase changes, like gas to liquid, aren’t chemical changes.

4. In this reaction there isn’t two chemicals involved just the sulfur hexaflouride which results in this also not being a chemical change.

5. In this next reaction, superabsorbent polymers (also known as hydrogels) is not a chemical reaction because the water would remain water when soaked up and the hydrogels would remain the same as well.

6. This also is not a chemical reaction because sodium acetate remains the same even t

7. This isn’t a chemical reaction either due to the fact that there is no indicator other than the change in temperature; there was no gas produced or color change.

8. This is a chemical reaction because gas is produced due to the fact that something is burning. This is known as a combustion reaction as well with a balanced equation of 6KClO3 + C6H12O6 = 6KCl + 6H2O + 6CO2 + 3O2

9. This is also a chemical reaction because again there is something burning which in this case is the magnesium and that shows it is a chemical reaction because gas is produced. This is known as a single replacement metathesis with a balanced equation of 2Mg + CO2 = 2MgO + C

10. This is also a chemical reaction that is again similar to reactions 8 and 9. There is clearly a gas being produced and something new is being created which indicates that it is indeed a chemical reaction. This is also synthesis and redox with a balanced equation of  2Na + Cl2 = 2NaCl.

My favorite chemical reaction had to be the Potassium Chlorate and Candy Reaction (Number 8) because it is a very dramatic display of a chemical reaction! It was mentioned that it was a disinfectant and included in fireworks and explosives. It really caught my attention because I didn’t realize how the combination of a simple piece of candy and some potassium chlorate could cause such an explosive and electrifying reaction. “When potassium chlorate is heated to melting point, any item added to it will cause a rapid disintegration in the form of an explosion”.

Sources:

Top 10 Amazing Chemical Reactions

Top 10 Amazing Chemical Reactions Article

3 Questions Blog- 4/25/2014

1. What tasks have you completed recently?

Recently, I have studied for and taken the ACT a couple of weeks ago and finally received my results of a 25 overall for my first time. In English, I have taken a vocabulary final and I have finished writing a personal narrative essay on my passion as a cheerleaders. Also for English, I have been continuing to read The Picture of Dorian Gray and have completed many ID writings and discussions to have a further understanding of the book. In chemistry, we have been practicing a lot with net ionic equations, oxidation, and reduction equations which I’ve completed notes and worksheets on in order to prepare for the upcoming test. In culinary, I have recently prepared and served an Italian themed luncheon for the staff as part of my culinary final. 

2. What have you learned recently?

I have learned that by the end of the year we are all just tired of school and start to slack off but then more and more work is being crammed and piled in at the very end of the semesters. I have stressed myself out recently trying to stay on top of everything so I have learned that you need to stay on top no matter what because as it nears the end of the school year there isn’t much you can do to save your grade anymore.

3. What are you planning on doing next?

I am planning on trying to become more organized and to pay attention as much as I can now that it is at the end of the school year. This is a time of stress and racing to get things turned in and I am going to study for all upcoming tests especially my AP US history test coming up in a few weeks.

 

Solutions Mini Lab

Today in chemistry we made solutions out of sugar/water and salt/water. A solution is known as a homogeneous mixture of two or more pure substances. These next two compounds make up the solution and that would be solute and solvents: A solute is what is being dissolved, and a solvent is what is dissolving the solute. For example, to make a solution of salt water, you would take salt, which would be the solute, and water, which would be the solvent. The solvent is usually in the most abundance and the solute is in the least. For our experiment we created a solution of salt water and a solution of sugar which made the water the solute and the salt and sugar the solvents. Just by looking at our solutions there was no way to tell which one was which so in order to figure this out we had go back to the basics and work our way up. We began with the clarification that salt which is NaCl was indeed an ionic compound while the sugar sucrose which is C12H22O11, was not an ionic compound. We used a light bulb with metal prongs attached to it and stuck the prongs into the solutions, to find that saltwater conducted and made the light bulb glow but the sugar water or the deionized water didn’t conduct the electricity to light the bulb.

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We hypothesized that the salt itself must break down into individual Na+ and Cl ions which would explain why it would conduct electricity if the current was passed through it. This also showed that the sugar water and deionized water wouldn’t conduct electricity. This experiment introduced us to electrolytes and nonelectrolytes. Electrolytes are known as substances that dissociates into ions when dissolved in water and nonelectolytes are substances that dissolve but don’t dissociate into ions when it does so.

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The above picture shows that you can create a particle diagram of a sodium chloride solution and a sugar solution. The sodium chloride solution would have water surrounding it evenly and due to opposites attract the water has a partial charge so the hydrogen will be facing the Cl but will be turned away from the Na because hydrogen is positive. The sugar solution will have the hydrogen facing away from the molecules because of the partial charge and will also have water surrounding a bunch of molecules.

Sources:

Class Experiment

Lab Notebook/Results

In class Discussion