Week 7 Reflection

In chemistry class this past week, we did a mini experiment involving water and ethanol in test tubes. One test tube had a designated amount of water in it while the other had ma atching amount of ethanol. Both had stoppers sealing off the top of them with narrow, straw-like tubes coming out of them. Each of the test tubes were placed in a flask of water over a heating plate. The heating plate was thne turned on and each of the liquids began to rise. As time went on, it became noticeable that the ethanol was rising more rapidly than the water was. We were then able to determine that as the liquid's volume increased, it's density decreased, which also caused the ethanol to rise faster than the water, for it was less dense. Since temperature is the measure of the energy (motion/speed) of the particles, we could then relate the speed of particles to the surrounding temperature. The average velocity of these particles all depended on the temperature, for particles do not move as rapidly at colder temperatures.

Another new idea that we were introduced to this week was the idea of pressure. Pressure is an inverse relationship of force over an object's surface area. For a steady force, the surface area must decrease in order for the pressure to increase; with a steady surface area, the amount of force must increase in order for the pressure to increase. We then came to the consensus that some of the factors that might affect gas pressure would be the number of particles, the volume of the gas, and the temperature. From there, we conducted an experiment to help us understand the relationship of pressure vs. the number of particles. We were to take a syringe and attach it to a Labquest, which would calculate how many kilopascals were being exerted throughout the experiment. A happy medium was established: 10 milliliters, which was where the pressure would be measured after each number of puffs. Each puff consisted of 4 milliliters of air and after each puff, the end of the syringe would be drawn to 10 mL to measure how the pressure was affected by more and more particles being added and taken away from the system. We then came to the conclusion that after each puff, the amount of pressure at 10 mL nearly doubled.

One of the other pressure experiments we did this week consisted of measuring pressure to see how it varied at designated mark. We first had to hook a syringe up to a Labquest's pressure sensor to help us obtain an accurate reading. If the syringe was pulled, the pressure would decrease, but if the syringe was pulled in, the pressure would increase. After obtaining our data, we noticed our graph looked a little more different than usual because it had a negative curve to it. In order for us to graph a linear function, we were informed that are volume measurements were to be inversed. This would help us equate the two things because they were now both consistently proportionate. By multiplying the temperature to the inverse of the calculated volume, we were able to obtain a more familiar graph, for pressure is inveresely relateed to volume at a constant temperature.