Unit Test Reflection

Overall I think the unit test wasn't as hard as I thought it would be. Don't get me wrong, it wasn't easy but it wasn't too bad. The night before the test, I started working on the guided readings while reading Unit 3 and 19 in the text book. When I got to Chapter 19 I realized we hadn't covered some of the topics in class and I panicked. So I thoroughly read the chapter and took the practice assessments in the schoology test prep link. Thankfully there wasn't much of Chapter 19.2 on the test but I'm really glad I read it because it gave me a better understanding of the topic as a whole. Since a lot of chemistry is linked together and knowledge that you acquire is often used in later topics; I think that having done all that will definitely help me in the long run. After I had read the chapter, I went through all the practice tests on schoology and I'm REALLY glad I did that because I found that the questions on the test had similar formats which gave me a feel for what I would be seeing. After doing the tests, I marked which problems I had trouble with and went back and reviewed that in our notes and the textbook. I really like doing practice problems before tests because I have noticed that it helps me a lot. As they say, practice makes permanent; and perfect practice makes perfect. (and that's the goal)

Star log reflection

The star log project was actually very cool and I enjoyed it a lot because astronomy has always been interesting to me. I think I even wanted to be an astronomer at one point in my life. I also think that this project was a lot less stressful than the Frontier Chemistry project because I think the first project prepared us for this one. (I'm also pretty glad we don't have to do an essay for this one) I think the information was a lot easier to find and there was less stuff we had to find. I also like how we got to pick which stars we wanted to research, I think it made it a little more exciting and unique. I think I did a better job of managing my time for this project, however if I could improve I would see if it were possible to find further information about the chemical composition of each star. I used the Harvard research base for a lot of my research but it was difficult to read through the abstracts and understand the terms that they used sometimes.


Some other useful links for this project: 
http://www.umop.net/spctelem.htm
THIS one is my personal favorite because they made easy to read charts with most of the information I needed
I also used Wikipedia a lot for background information about stars and constellations

Half Life

In this unit we learned about how to calculate half lives. Half lives are the time it takes for half of a sample of atoms to decay to a stable form. For example, in the Forensic archaeology lab, we calculated half lives of the radioactive atoms in a sample. The formula for calculating half lives is listed below. Half lives can be used to trace the amount of time a sample/remain has existed. That can be used in crime scene investigations to determine how long a person has been dead. At first, when we started this section I was actually really confused and was confused especially when we were given word problems. However, the lab that we did (the forensic archaeology lab) helped me solidify my skills.

http://www.m2c3.com/chemistry/VLI/M3_Topic2/la_06_13.jpg

Useful links:
http://hyperphysics.phy-astr.gsu.edu/hbase/nuclear/halfli.html
http://www.coolmath.com/algebra/17-exponentials-logarithms/13-radioactive-decay-decibel-levels-01

Forensic Archaeology lab

In this lab, we used paper instead of radioactive molecules to get a feel for how half life works. This lab also helped us practice calculating half life and understanding what the calculations mean and why the specific formulas are used. The formula to calculate half life is: # of radioactive atoms initially/ 2^half lives. To calculate backwards to determine the original radioactive mass from the half life mass, we use the formula # of radioactive atoms*2^half lives. After calculating the data from this sample experiment, we use the collected information to apply it to the real world problem given and use the information of half life decay to determine how old in years an artifact (body) is. I think this is a good experiment that not only helps us practice calculating half life, but we also understand how half life calculations are used in the real world. I think applying acquired knowledge from lectures to real world or hands on activities really helps me understand concepts better.

Quiz

I think I did pretty good on this quiz. This unit, I am doing slightly better because I am getting more used to this class and getting more accustomed to how to study. This unit seems to consist more of the math skills that Chemistry is known for. I hope to do well in this unit because math is one of my strengths. This quiz reflects my understanding so far in this unit and I feel like I have a pretty good understanding of the material so far. I was also able to raise some of my grades in the previous objectives in the nomenclature unit. I am glad that I still remember that unit because I know that is a very important part of chemistry/this class. To prepare for the upcoming unit test, I need to practice with practice problems from schoology and from the textbook. That is how I studied for this quiz and I think it really helped. Therefore, I plan on using this study method more often.

Mass of Subatomic Particles

In today's lesson, we learned about masses of subatomic particles. First, we learned the labels of an element in a periodic table because that is what we use to determine a lot of things in this unit. (see picture below). The letters in the middle are the Element symbol, the name below is the element name, the number at the top is the atomic number (the number of protons and electrons), and the number at the bottom (usually a decimal) is the average atomic mass. Then we leaned the notation for recording different isotopes of an element. Which is done by using the element symbol and two numbers on the right (see picture below). The number on the top is the mass number and the number on the bottom is the atomic number (number of protons/electrons). The number of neutrons can be determined by subtracting the atomic mass by the number of protons. Then, we learned about calculating average masses and percent abundances of isotopes. The formula for calculating average atomic mass is (mass of one isotope)*(% abundance)+(mass of other isotope)*(%isotope). This same formula can be used to figure percent abundances when average mass and isotope masses are known.

Element on periodic table labels

picture

Isotope notation

picture

Extra resources:
calculating practice: http://www.chemteam.info/Mole/AverageAtomicWeight.html
http://blog.wsd.net/hewaite/2014/10/ 
http://ehschemcorner.blogspot.com/2012/09/the-atom-isotopic-notation.html 

Atomic Theory and Nuclear Chemistry

The notes that we took today seemed more informational than the last unit. The last unit felt like it was more of application of rules. Today, we took notes on Dalton's Atomic Theory, Law of Constant Composition, JJ Thomson, Rutherford's Gold Foil Experiment and the current Atomic Model (the cloud model). To remember each of these scientist's discoveries and importance, my friends in other chemistry classes made acronyms. Knowing those acronyms, its already easier for me to remember these scientist's roles than it would have been if I had just tried to memorize them today. The activity that we did at the end of the notes (the obscur-tainer lab) today was also fun. There was a small black dish with a shape inside and a small metal ball; and we had to roll the ball around to guess what the shape was inside. This kind of relates to how Rutherford did his Gold Foil Experiment because he used other elements (ex: the metal ball) to bounce off the gold (the shapes) to figure out unknown properties of Gold.

Gold Foil Experiment (Rutherford)

http://wps.prenhall.com/wps/media/objects/476/488316/Instructor_Resources/Chapter_04/FG04_04.JPG

Thomson's Cathode Ray experiment

                                                                                                                               http://www.physicsoftheuniverse.com/topics_quantum_atomic.html

Extra resource:
https://www.boundless.com/chemistry/textbooks/boundless-chemistry-textbook/atoms-molecules-and-ions-2/history-of-atomic-structure-32/john-dalton-and-atomic-theory-197-6138/
http://www.physicsoftheuniverse.com/topics_quantum_atomic.html

Unit 2 Pre-test

The pre-test that we took on Tuesday was really difficult. I didn't know the majority of the answers. However, on some of the questions, I was able to use prior knowledge of chemistry to make an educated guess. Also, as I continued I recognized that there was probably a pattern in the questions with the atomic masses and etc. The test also included sections where I had to read and answer questions about graphs which wasn't as hard as the rest of the test because we were able to use prior skills of reading scientific graphs.