Chemical Reactions Combustion Demonstration

This afternoon we witnessed three demonstrations regarding combustion. To begin, we saw how heat reacted with ethanol. What our teacher, Miss Leland, did was to put roughly 20ml of ethanol into a two liter soda bottle, and mixed it around so the ethanol coated the bottle, and the rest of the ethanol became a gas. After a while, she opened the lid and poured out the excess ethanol, and set the cup back down on a table. She proceeded to light a flame over the lip of the bottle. Suddenly, a flame lept about the inside of the bottle, consuming the ethanol instantly. After the combustion, several tablespoons of water were left over. This was a prime example of an exothermic reaction, which is when heat is generated off of the bottle. This reaction was one that separated the water, from the carbon dioxide.

She also conducted a test containing baking soda and vinegar. When placed together in a flask, they immediately start to foam. The top was quickly covered, as to contain the gas inside the flask. After removing the cover, she put the mouth of the flask towards two lit candles, and they blew out immediately. This was due to the carbon monoxide that was created had stifled the oxygen around the flame, and a flame needs oxygen to survive.

The last test was using pool acid. When pool acid and since were added to a beaker, and a flame was placed near it, the mixture would combust, and stay alive for roughly ten seconds, before our instructor added even more zinc, which caused the flame to leap up again for a short while. This experiment lasted the longest of all of our tests, and in my opinion, was the most amusing. Something about the zinc and pool acid caused a flame to be sustained for a short while. This shows how certain chemicals react with heat in different ways.

Chemistry Reactions and Heat Lab

Questions:
How does heat create chemical reactions?

Hypothesis:
Heat will accelerate chemical reactions due to the energy transferred, making the atoms more excited.

Results:
Cody and I took an alka-seltzer tablet and put it into water of three temperaters. First, our hot water test. When we placed the tablet into hot water, the fizz that it was created was instant, and fast. The temperature was 50 degrees Celcious, and the time it took to dissolve was roughly 25.19 seconds.

The room temperature lab was slightly different.  This time, when the tablet was inserted, it took a little bit longer to disolve, clocking in at 33.67 seconds. This could be because the water was not as warm, therefore not transferring the energy that makes the molecules more excited. The reaction happened slower, and longer.

The final test we conducted was the cold water test, which involved placing a tablet into a cup of water with ice. The temperature was about .5 degrees celcious. When the tablet fell in, my lab partner and I knew it would be quite different from the tests before. This test lasted a whole 2.33.53 minutes. We predict this was becuase when hot water sped up the resuts, the cold water slowed them down.

In conclusion, my hypothesis was correct. In hot water, the reaction was faster. In cold water, the reaction was slower.

This is an average graph, showing how the higher the temperature, the shorter the time it took for the tablet to disslve. The colder the temperature, the longer it took for the tablet to dissolve.

Freezing and Melting Water

Freezing and Melting of Water

Hypothesis:  If the probe is put into the ice water and then warm water, we will obtain a freezing and melting point, the melting point being higher than the freezing point. The freezing point should be roughly 0 degrees Celsius, and the melting point should be roughly 5 degrees Celsius.

To start, my partner and I had started with a 600 mL  beaker, filled roughly one third of the way with ice. We also added roughly five tablespoons of salt. We added a temperature probe, and added it to the ice water. We calculated the mean, median, and minimum and maximum temperatures. After recording the freezing point of water, we let the thermometer thaw out a little, then we calculated the melting point of water. It would be seen that the freezing point of water was about .5 degrees Celsius.

This is an image of our freezing water data after fifteen minutes. At first, we added the probe o the water. The stats read as follows : Mean- .5645. Median- .5895. Minimum temp- .3113. Maximum temp- .6426. Those are the results for the freezing test. All of our data, for both the cold and warm water test, is recorded here.

The above is an image including the freezing point and melting point. One of our mistakes, however, was that my group mis-labeled our points, so please disregard that information. What is labeled as the freezing point it actually the melting point, and vice versa. Our melting point turned out to be roughly 4.7 degrees Celsius.

In conclusion, my hypothesis was correct. The freezing point was just above 0 degrees Celsius, and the melting point was just below 5 degrees Celsius. If I was to change the experiment in any way, I would spend a little more time with more advanced settings of Logger Pro, so  I could be more exact on my scientific results.

Greatest Discoveries in Chemistry

Chemistry has made many scientific break throughs in it’s time. It has helped humankind better understand ourselves, and the world around us. Chemistry covers anything form the oxygen that surrounds us, to how a specific molecule can form a ring to create an element.

Starting with the atomic theory, with John Dalton, the range of knowledge in chemistry has only grown. John Dalton had the notion that perhaps gasses were made of more than one atom. Also on the subject of air, in addition to the four main elements of air, water, earth, and fire, Da Vinci thought that perhaps air was two elements, oxygen and air.

Another scientist by the name of Fredric Voire artificially made urea. Urea is normally produced by a human kidney, but when Voire was successful, he had opened the door to countless other artificial makings. This showed that you can create specimens like that from natural resources, chemically.

Most scientists had already experimented with atomic structures, but they were stumped on a certain element. Kekule had then discovered that some elements can form into rings, instead of the classical chain shape. This helped discover many other elements.

One of the most famous tools for science is called the Periodic table of Elements. This is a chart that lists all of the elements, their mass, and their number of protons and neutrons. It all started when a physics teacher was trying to think of a more efficient way to teach his students all of the elements. He created a card for each of the elements, and started randomly grouping them. Soon, he began to notice patterns in the elements. Then, he finally found the correct formation. He was even able to predict where new elements, that hadn’t even been discovered, would go.

Another of the great chemistry discoveries is one found by Dimitri Mendevelium. He had discovered that electricity can transform chemicals. He had at first, successfully transform pot ash into potassium. This discovery lead to the creation of aluminum, L.E.D. lights and displays, solar panels, and even rechargeable batteries. Many more creations have been made from electricity's transformations.

Robert Bunsen was the scientist who realized that atoms had unique signatures of light. It all started when he created the spectroscope, a device consisting of multiple telescopes. He would then place atoms in a prism, and when he looked through the telescope, it revealed a gradient of color with specific patterns etched vertically into them. It was from then they were able to trace what elements were in atoms.

All of these discoveries helped shape what our world is today. Without these discoveries, modern science could be non-existent.