Reaction Rates and Equilibrium

Reaction Rates and Equilibrium

Today, in Chemistry, we learned about the topic of reaction rates and equilibrium. At the start of this standard, we discussed the collision theory. The collision theory dictates whether molecules have the capability to react. There are three key ideas in this collision theory. The first part of the theory states that molecules have to collide in order to react. Next, it also states that molecules have to collide in the correct or appropriate orientation. Finally, the last part of this collision theory tells us that the molecules have to collide with sufficient energy that is equal to or greater than the activation energy barrier.

 After this big idea, we learned that the reaction rate in a reaction is proportional to the number of effective collisions. There are five factors that determine the outcome of the reaction rate. These factors include temperature, concentration, surface area, pressure, and the nature of the chemicals that are involved in this reaction. We also learned that catalysts are useful for speeding up chemical reactions because they lower the activation energy, giving more molecules sufficient energy that is greater than or equal to the activation energy barrier. This standard also required us to identify the difference between chemical equilibrium and physical equilibrium . Physical equilibrium is equilibrium in a reversible reaction that does not change the identity of the substance. An example would be water in a closed system. The forward reaction rate of water (liquid water to vapor) is equal to the reverse reaction rate of water (vapor to liquid water). The same property holds for chemical equilibrium. We also learned how to perform mathematical calculations that tells us whether the equilibrium favors the products or the reactants of a reaction.  Finally, we learned that changing the pressure, concentration, or temperature, may change where the equilibrium lies. This idea was derived from Le Chatelier's Principle.

This is the mathematical computation that can show us where the equillibrium lies.
https://docs.google.com/presentation/d/1Qx09c1p7p2kNM_WwcYIrtiJAPnS2z__
hh926KYI0Ko0/edit#slide=id.g25a36e971_4_59

http://science.wonderhowto.com/how-to/classic-chemistry-colorize-colorless-liquids-with-black-magic-aka-iodine-clock-reaction-0139128/

Synthesis and Decomposition

Synthesis and Decomposition

First, we learned about the definition of a chemical change. A chemical change results when substances chemically react to produce a new compound(s). Next, we learned about  the processes of synthesis and decomposition. Synthesis is when two or more reactants react chemically to from one product. Decomposition is when one reactant splits into several compounds or substances. Synthesis and decomposition reactions are technically the same processes, and they are just flipped vice versa.  Also, we learned how to use the ember from a burning splint to determine what gases are being released.  If carbon dioxide is being released, then the ember will fade. If oxygen is released, the ember will continue glowing without exploding. If hydrogen is being released, then the ember will explode.  We also learned how to predict the products of synthesis and decomposition reactions while using phase symbols:

Phase symbols: s-solid, g-gas, l-liquid, aq- aqueous 

This is what happens when you put a splint with ember when oxygen gas is being released. http://physical-science.tripod.com/id25.html

Acids, Bases, pH, pOH, etc.

Acids and Bases

In this lesson, we learned about the definitions of acids and bases. The definitions of acids and bases are determined separately by two very different theories. The Arrhenius theory states that the acids have a low pH and that bases have a high pH on the pH scale. It states that acids have a high hydrogen concentration, whereas bases have a high hydroxide concentration. We also learned that if you add water to a base or acid, the pH of the solution will head to be neutral (7). If a substance has a neutral pH, like water, then the substance also has a neutral pOH (measures hydroxide). We also learned a formula chain that helps us find the pH, pOH, hydrogen and hydroxide concentrations of a substance or a solution. The formula chain is shown below. 

This formula chain can help us find the concentration or pH and pOH of a substance. 

We also learned that acids are sour, react best with metals, and they are slimy. Bases are not as slimy, bitter, and do not react with metals. The more acidic a solution is, the better it is at conducting electricity.

Gas Laws Reflection

Opinion on Gas Laws

This week, our chemistry class learned about gas laws. This standard covers on the topic of what is the definition of an ideal gas is. Basically, an ideal gas is a type of gas that can never be changed into any other state of matter. Although this idea was created, there is actually no ideal gas (imaginary gas) that can be found in the universe because all gases can change into different states of matter according to different atmospheric pressures and temperatures. We also learned how to use the ideal gas law equation to help solve for unknown variables including pressure, volume, number of moles, and temperature. The ideal gas law equation is in the form of: 

pV=nRT

where P is the pressure, V is the volume, N is the number of moles, R is the ideal gas constant, and T is temperature. 

This equation can also help us find relationships between two or three variables like finding how changing the pressure of a gas affects the volume of a gas.  Overall, this standard was a little confusing because some of the rules for a gas to become ideal is counter-intuitive because every gas does not follow that rule or kinetic theory.  I also cannot wait to learn more or be interested about stoichiometry since this is supposed to be the hardest subject that tortures every student. Plus I'd like a good challenge! 

Heating Curves

Heating Curves

Adding sugar to water makes the water freeze faster (lower boiling point)
Link: http://www.123rf.com/photo_7903331_a-glass-of-water-with-sugar.html

Yesterday in our chemistry class, we conducted an experiment to observe the boiling and melting points of four different substances: water, water with sugar, saltwater, and water with sugar and salt added. Due to the differences in polarities, these substances caused a significant difference in the boiling and melting points of the substance. It turns out that adding salt to water results in the highest boiling point and melting point, and adding sugar to water results in the lowest boiling point and lowest melting point. Plain freshwater has the second highest boiling point and melting point, and sugar and salt water has the third highest boiling and melting point. We also had to graph our heating curves, and we predicted that as time increases, the temperature of the substance would undergo an exponential growth. At first it did undergo the process of exponential growth; however, when the substance reached its boiling point, the temperature started to stabilize. In actuality, the heat is actually stabilizing the electrons. This is why we add salt to sidewalks to keep the water from turning into snow. If we were to add sugar, it might make the water freeze sooner than the amount of time it takes for that of regular freshwater. As stated our graph compared to other data shows that this substance has the lowest boiling point, meaning that it will make the water freeze faster.  

Credibility of Sources

Dihydrogen Monoxide is "Harmful"

Recently, our chemistry teacher has talked about determining which types of sources are reliable. In order to master this concept, he made us read this article claiming that there is a chemical, known as "dihydrogen monoxide", that can be very dangerous. According to this article, contact with this chemical can cause genetic mutations, affect protein cells, and damaging neurotransmitters, which is the main component of signals that are used in our nervous system. Due to this claim, this website recognizes dihydrogen monoxide as a carcinogenic substance, meaning that this chemical causes cancer. It is also claimed that one drop that we consume of this chemical could lead to immediate death. This substance or chemical can also cause tissue damage, soil erosion, and it was claim to be present in cancerous tumors as well. Also, this chemical was claimed to be used in nuclear power plants. It was claimed to be used as a bio terrorist weapon during World War II, and the article claims that it has been used by other terrorist organizations, including the al-Qaeda. This article tells us to watch for symptoms if we consume too much of this chemical. Symptoms include: excessive urination and sweating, vomiting, nausea, bloated feeling. Although this article says that dihydrogen monoxide is harmful; however, this chemical is the same thing as the chemical for water. In my point of view, this article is totally unreliable and built on lies. The reason as to why this is not factual is because of the fact that we consume a large amount of water everyday, yet we do not experience any of these symptoms stated in this article. We use water in our everyday lives, but we do not experience the detrimental health effects that are predicted by this article. Overall, this article is not a credible source. 

Dihydrogen monoxide, or water, is claimed by an unreliable article to be a "harmful" substance.
Link: http://www.clintonhealth.org/boilwaterorders.html

Diatoms From Space" Speculation

Diatoms Came From Space

In the United Kingdom, a research was carried out on the last day of July this year. Scientists tried to take samples of the composition of our stratosphere, which is the second layer in our atmosphere.The stratosphere is about 25 kilometers to 27 kilometers above sea level. In order to perform this task, scientists came up with a way to take samples of the stratosphere by launching sterile electron microscopes to collect samples of aerosols in the atmosphere. Greater than 25 km, the microscopic stubs revealed that there is a presence of diatoms. Diatoms are tiny, microscopic plant organisms that are unicellular, meaning that they have only one cell. Scientists are starting to come up with a theory that explains how the diatoms are present in Earth. They think that these diatoms originated from outer space, and the diatoms eventually reached Earth by the transport of a comet. 

They were able to perform this experiment during the Perseid meteor shower that took place in the middle of July. As a result, there are two possible ways about the origin of the diatoms that are found in our stratosphere. The diatoms either came from the surface of the Earth, or it was going from the opposite direction, meaning that it was falling from space. However, the only way for diatoms to reach the surface of the Earth is that if it travels, by force, from a violent volcano explosion. There is more evidence that supports that diatoms came from space because a similar discovery was found in the eastern country of Sri Lanka. Scientist reported possible presence of diatomic creatures found on a meteorite that fell in that particular area. If diatoms were to come from space, this would mean that we would have a direct evidence of extraterrestrial life. This is very important because if we have a direct evidence of extraterrestrial life, then we can conclude that we are not the only type of living things in the universe. Also, it may spark up the process of panspermia, which is the idea that all life on Earth originated from space.

However, there is an article that supports the idea of panspermia and the idea that these plant-like diatoms came from space. It states that if the diatom were to come from the comet, it would not be clean of rock or other matter. This supports the point that diatoms do not have an extraterrestrial origin because if it came from the comet, it should have the opposite appearance. This article claims that the only reason that scientists are saying that diatoms are extraterrestrial forms of life is because that these scientists did not have any other special reason that these organisms could have came from Earth. Basically, scientists use this theory as a variable that represents something unknown (where did diatoms come from?).

This is a microscopic, zoomed image of a diatom that is found in the stratosphere. Many scientists theorized that it has  extraterrestrial origins.
Link: http://www.theblaze.com/stories/2013/09/19/scientists-very-very-confident-theyve-found-extraterrestrial-life-see-what-it-looks-like/