Thursday, July 7, 2016

Exam Day.....yay.

Senior Science Final Exam

Nicholas Garner

                                             



1.    What was the purpose of the pancake lab?  Explain the point of the lab, why did we do it.  List and define four key terms you learned from the lab.

~The purpose of the pancake lab was to demonstrate what a homogenous mixture was. I learned that homogenous means a uniform mixture like mixing salt with water. Heterogeneous means the mixture is not uniform like when you mix pebbles and water. I learned the proper definition for a mixture. I also learned about your daughter!


2.  What is a vector?  What two attributes do vectors have?

~Vectors are lines. Vectors have both magnitude and direction. At the same time that we were learning about these in science, we were learning about them in math, so it really helped to have double the info on the topics. I learned that vectors and scalars are something that applies to life on a daily basis, we just often miss it.

3.   Complete the sig figs below:
 Indicate how many significant figures there are in each of the following measured values.
  • 246.32 (5)
  • 107.854 (6)
  • 100.3 (4)
  • 0.678 (3)
  • 1.008 (4)
  • 0.00340 (4)
  • 14.600 (3)
  • 0.0001 (4)
  • 700000 (1)
  • 350.670 (5)
  • 1.0000 (1)
  • 320001 (3)

4.    Explain what the Law of Conservation of Mass describes.  How is this important in chemistry?  Give an example.  Be sure your response proves your expertise in this question.

~The Law of Conservation of Mass states that matter can be neither created nor destroyed. Like when a piece of paper catches on fire. The paper burns into ashes that fly away. Those ashes are the same mass that the paper was before it caught fire. This is important to know and study so we can figure out where matter is reused and recycled.


5.  Discuss how force and mass are important in chemistry.  What is their significance?

~Together, force and mass equals acceleration. Acceleration tells you how fast you are going. This is important because, with it, we can track how fast asteroids are going, how much force an entity is exerting, or even how much mass something has. That is really important to know how to do when it comes to science.

6.  Explain the chemical reaction that occurred in the egg explosion?   What gas is produced and why did some eggs delay their explosion time?

~The egg explosion was an awesome combustion experiment. In it, we created hydrogen gas, that of which filled the Hindenburg. After we had filled them with gas (by sitting them on a beaker containing acid and zinc), we then took them off, set them on another beaker, and held a flame to the top of the egg. That was soon followed by a loud "pop." Some eggs (mine...) delayed because, first of all, the gas was running low within the first beaker, but also because the air was taking a while to rush in the egg and ignite.


7.  Use the example of  a trash can help explain a heterogeneous mixture vs. a homogenous mixture.  How are they similar?  How are they different?

~A trash can is a really good example of a mixture type. In a trash can, you have all kinds of bits and pieces of unwanted paper, gum, and etc. The actual trash inside of the trash can can be considered a heterogeneous mixture because everything is different within and not combined as one. In a homogenous mixture, everything would be combined such as when you pour chocolate syrup in milk.


8.  Explain how the tie dye lab related to what was studied.   Be sure to talk about cotton fibers as explained in class.

~The tie dyeing after soaking the shirts in sodium bicarbonate was a really fun experiment. The sodium bicarbonate opened up the cotton fibers in the shirts because they're usually tight and closed. Since the cotton fibers were opened and relaxed, they took hold of our colors better and came out brighter in the end. this relates to class because we have been talking about reactions all summer.


9.   Compare and contrast the similarities and differences between dependent and independent variables.  Give an example and explain the mnemonic device used to remember where to graph the variables.

~Dependent and Independent variable both work together, especially when used on graphs, to show the relations and ties within experimental data. Both independent and dependent have two different meanings. Independent is that which is changed by the scientist while dependent is that which is changed due to the independent variable. A mnemonic device we used to remember this was a simple little x and y graph that had a big "D" on the y-axis and an "I" falling from the x-axis.


10.  What is the  difference between accuracy and precision?  Why is this important in sig figs?

~Accuracy is being able to shoot arrows and has them all land where you want them to go, yet not be very precise. Precision is having the ability to shoot arrows and have them all land in the same place multiple times, though that may not be the bullseye. Really, you do not just want one of these, but both of these because they work together to give "on-point" results. This is really important in sig figs because you want your answers to be as close and accurate as possible.