Week 6 Reflective Post

Starting off this week, we dove into right into chapter 6.  The very first worksheet we did was the Thomson Model of the Atom.  This worksheet examined the experiments of J.J. Thomson, a scientist who did multiple experiments with Cathode Rays.  He did three experiments that helped him come up with his model of the atom.  After the three experiments, he concluded that the rays are made up of extremely small particles known as electrons.  He also discovered that these small particles have a negative charge.  After these experiments, he also came up with a model of the atom known as the plum pudding model, as the model kind of looks like a plum pudding.  This worksheet helped us gain a better visual of what electrons in atoms look like and they interact with other charges.
Our first lab of the week built on the the knowledge we learned from our first worksheet.  Known as the stick tape activity, we experimented with the different reactions tape has with strips of paper, aluminum foil, and other tape.  We observed that when we rip the two pieces of tape apart, the two pieces of tape gain an electrical charge,  However, the top one has a positive charge and the bottom one has a negative charge.  After putting the two pieces of tape next to the various strips of materials, we realized that like charges repel each other and opposite charges attract each other.  As most of us knew this information, this activity just built on a foundation of previous knowledge, however, it was till beneficial as it gave us specific examples of how these properties worked.
Following up the sticky tape activity and the worksheet we did with it, we went over a sticky tape post lab worksheet that reinforce our understanding of the lab and why the tapes attracted and repelled each other at certain times.
The next lab we did was an experiment to see what substances are conductors and what substances aren't conductors.  We went around and looked at 15 different substances, and tested their conductivity with our conductor stick.  Basically, if they were conductors the LED on the stick would light up,  If it didn't conduct, the stick didn't light up.  From this experiment, we discovered that all metals conduct, no matter what form they're in.  We also discovered that only a certain number of non-metals conduct and most of them only conduct if they are in a certain state, such as a liquid.  This was a very eye opening lab as we could see what elements and compounds are conductors and what aren't.  We can easily relate these concepts to our daily life.
Finally, the last lab we did was an electrolysis lab.  We attached a positive charge and a negative charge to two separate ends of a u-shaped tube that held Copper chloride.  Once we turned on the electricity, we discovered a very interesting concept.  Because the chloride was on the negatively charged side, it was attracted to the positively charged side and eventually it went all the way around the tube and evaporated.  The opposite happened for the Copper.  Because it was positively charged, it was attracted to the negatively charged side and it formed copper crystals underneath the conductor.  This electrolysis lab was extremely helpful as it demonstrated another way that positive and negative charges can be demonstrated.

Before

After

We finished off the week with the Worksheet 1 of Unit 6 which basically had us comparing ratios of ions in certain compounds.  Hopefully we will do more experiments involving conductivity and elements, as they're really fun and interesting.

Week 5 Reflective Post

This week was an interesting week, as we had two of our class hours interrupted by testing.  The first was the PSAT, which wasn't very hard, it just took up a lot of time.  On that day, which was Wednesday, we only had 20 minute classes so the class period wasn't that productive.  On Friday, we had our unit 5 test, so that took about 45 minutes and then we had the rest of the hour to do other work and study for other classes.  I thought the test went pretty well and I'm excited to get my test score back.
Earlier in the week, we went over the worksheet we did over the weekend for homework.  We did a lot of white boarding which always helps me because I can see what other groups got for answers and also how they got them.  Also, if I don't know how to do a problem, other groups explaining their whiteboards always helps me figure out the correct answer.  Earlier in the week, we also took a quiz on finding the masses and moles of certain elements.  The quiz was about a page, but it still had many meaningful problems that helped us exercise the processes and skills we had learned the week before.  Even though I got a 8/8 on it, I still learned from it because I made a few sig fig mistakes that helped me better understand the concept of sig figs and how to get them correct in the future.  I'm really happy Dr. Finnan didn't take points off on the quiz for that.  After we had taken the quiz, I for the most part felt like I had mastered the material as I did well on the quiz and I had been periodically studying for the test coming up on Friday.

Thursday (the day after the PSAT), we worked on and went over the review packet.  This packet consisted of all the different concepts and ideas we had went over that pertained to the Unit 5 Test.  It included everything from finding the amount of moles in a certain amount of grams, finding the percent composition of a compound, relative mass, and more.  It also had a problem like our Empirical Formula lab which kind of hinted that we might have a problem like that on our test.  It was overall a great practice for the test because of all the practice problems it gave us.  I felt really confident for the test after completing this packet, because I had gotten most of the answers correct.
Overall even though this week was kind of weird because we had two tests, I still felt like I learned a lot and I'm excited to enter into next weeks unit.

Week 4 Reflective Post

Probably the biggest point of this unit is the mole.  The mole is what we've been focusing on for the past week.  We've done sample problems involving this concept and we also did a lab to further educate ourselves.  To quickly review the stuff we covered the week before, we did another worksheet with relative mass, but this time, we also introduced the mole a bit more.  As we got through the worksheet, we continued to do relative mass problems and by the end, we had related those to the mole, and had learned that there are 6.02x10^23 atoms in one mole.  This one concept is very important as it's what we focused on throughout the whole week.

To further our education on the mole, we did a worksheet that just had number problems involving the mole.  We were given a number of scenarios and from there we had to calculate relative mass using our knowledge of the mole and how it relates.  I really liked this worksheet because it helped me solidify my understanding of the mole and how it relates to relative mass.  We continued practicing our knowledge of the mole in the first couple days of the week, but during the middle of the week we started a lab.
This lab was called the Empirical Formula lab, and it mainly focused on the mole.  To start off the lab, we had to measure the mass of a beaker, and then the mass of that same beaker with a couple grams of zinc in it.  Once we had measured these out, we poured 50 mL of HCl into the beakers, and then we put them in the fume hood for the rest of the day.  The next morning we got to class and we had discovered that the reaction between the Zinc and HCl had formed a crusty like substance.  After this discovery, we heated up the substance to get rid of any excess water so we could take the final mass of the compound formed.  From this point, we calculated the masses of the two elements reacted and also how many moles were in each element.  Our final task was to find the likely whole number ratio between the two elements reacted and also to write out what we thought the chemical formula would be.  Finally, after we had done all the busy work, we wrote our data up on the white board and compared it with other groups data.  For the most part, we had gotten around the same values, but for some reason our ratio we discovered was almost 3:1, not 2:1.  Seeing this, we realized that we had made a mistake in our calculations, because every other groups ratio was 2:1.  We couldn't pinpoint the exact area of scientific error, as there were many contending spots.  Overall though, this lab taught us (in a fun way) how to discover the masses and moles of elements an compounds with just a simple amount of information.

To finish off the week, we we're given a worksheet that we were to do over the weekend.  It was another worksheet that covered moles and how to calculate them with just the given mass and formula of an object.  It was actually a very helpful worksheet as it gave us more practice and helped us solidify the concepts we learned this week.  I'm excited to keep learning and doing fun labs such as the one we did this past week.  Who doesn't like using fire in class?

Week 3 Reflective Post

After we finished Unit 4, we started on Unit 5.  So far in this unit, we've covered concepts such as relative mass and molar masses of elements.  We know that from the periodic table, elements have specific set masses.  For example, oxygen has a set mass of about 16 units and Neon has a set mass of about 20 units.  These masses also determine the relative sizes of atoms in an element.  The first worksheet we did to help model relative mass and how to calculate it was a worksheet where we had to calculate the masses of a few vials with different objects in them.  From there, we answered different questions that analyzed the specifics behind calculating relative mass and how we can apply it to modern day life.

Moving further into the worksheet, we had to do some conversions and calculating to get our answers.  Dr. J. showed us a very interesting method that is very helpful once you get the hang of it.  All you need to do is plug in the values and move around some units, and you have your answer.  One of the main things I need to remember to do is label my quantities.  I keep forgetting to label when doing the problems and then halfway through I don't know which values are which so I get very confused.  One great thing about this class is the white boarding.  When I was confused with a  couple of the problems I looked at other groups whiteboards.  This really helped me as I could see the  solving process the groups went through and how they came to my answer.  After completing some of the white boarding, I was able to go back and finish the worksheet with a better understanding of the concepts.
Further into the week, we did a second worksheet which was titled Unit 5 Worksheet 1.  Whereas the first worksheet covered just finding relative mass, this one introduced the concept of molar masses of the elements.  One of the very first questions asked us to portray how much more massive oxygen molecules are compared to Hydrogen molecules.  This was a great question to kick off the worksheet as it gave us the basic idea of how the molar masses compare.  Because the density of Oxygen gas at standard T and P is larger than the density pf Hydrogen gas at these same conditions,  You would draw the oxygen atoms much larger than the hydrogen atoms because of the density differences.  Calculating how much more massive something is was also very helpful because it provided a thoughtful visual.  We finished off the worksheet by comparing the masses of certain elements if they combined in a 1:1 ratio.  These problems helped us practice calculating the different masses and it gave us further knowledge on the reactions between elements.
Overall, these worksheets were a great way to start our journey into Unit 5.  They gave us lots of practice in converting and calculating, which is something you always want to know how to do as a scientist.  I'm excited to forage further into this unit while continuing to gain new chemistry knowledge and science knowledge in general.