SG Chem - Sixth Post

This week in chem 2 we started learning a new unit and to do this we did a lot of experiments. We did the sticky tape lab, the conductivity lab, and the "u" tube lab. I think my favorite lab was the Sticky Tape lab, which was a way for us to understand the interaction between positive, negative, and neutral charges. We started by taking two pieces of tape, placing one on top of another and then quickly pulling them apart to give them a charge. Then we hung them up next to a strip of paper and foil. We created another set of charged tape and then we tested the reaction between the hanging charged tapes (top and bottom), paper, and foil.

The hanging foil and paper before tape is charged 

The process of charging the tape
Right before separating the top and bottom pieces of tape

The hanging foil, paper, and two charged tapes
The two tapes were moving slightly because of their attraction to one another

The top tape had a positive charge while the bottom tape had a negative one. When tested against the foil, paper, and another set of top and bottom tapes we found that each tape attracted the foil, the paper and it's opposite charged tape, but it repelled against it's same charge (i.e. positive repelled positive, negative repelled negative). We also observed that when the two tapes were together, they had neither a positive nor a negative charge because they weren't attracted to anything. This must've meant that the two tapes had the same amount of electrons but when separated, the amount of electrons became uneven. We came to this theory because the two tapes (positive and negative) were now attracted to each other compared to before we put them together to create the charge. We discussed this as a class and came to the conclusion that the electrons became uneven NOT when the two tapes were pulled apart, but rather when the two tapes were put together. Somehow at that point some electrons "jumped" from one piece of tape to another, creating unbalanced amounts on each piece of tape. This is what created the attraction and repulsion between the two tapes.

I really liked this week in chem because we got to do so many things, and each class was very interesting. Something I'm still struggling with is understanding what our "u"tube lab helped us learn. I think that it's partially I'm forgetting because it's new information. I remember going over it on Friday, but because I didn't take a picture or notes, I can't remember exactly what it taught us. Another thing I don't fully understand is how you know how many electrons switch on the two tapes in the sticky tape lab. For the post lab we took notes and I have the amount of electrons switching from a three positive three negative, to a two positive four negative and I don't understand how you'd know that only one electron switches. 

I think my participation was pretty good this week. I helped with the labs, and asked my table mates questions. I think what I need to improve on is asking for help until I understand the concept, because I'll ask once or twice, but I feel bad for asking too many times, so if I don't understand I'll just leave it, which is bad because then I can't learn it. I need to work on the persistence to find the answers in a way that makes sense to me. Because of that, and the fact that some of the post lab things confused me slightly, I would rank my understanding of these week as a 6/10. 

SG Chem 2 - Fifth Blog

This week in Chem 2 we really didn't do any experiments, instead we did a lot of reviewing for the test that was this Friday. On Monday we took a quiz that measured our understanding of how to convert moles to grams, grams to moles, and moles to atoms.

On Tuesday we learned/reviewed how to find the empirical formula when we were given the amount, in grams, of certain elements. Then we learned how to find the molecular formula of the compound after we found the empirical formula. At first I didn't understand how to get the number you multiply the empirical formula by to get the molecular formula, but after going through an example I figured out how to do it. I really like doing this type of problem because the math makes sense to me.

Thursday we worked on a review sheet. It was good to go over the review guide as a class because it helped me get a better understanding of everything, while also jogging my memory on how to solve certain problems. For example this problem on the Chemistry - Unit 5 Review:

The Chemistry Unit 5 Review Question 3
It wants us to find the relative mass/mass of each different piece of hardware

This was a question based on the lesson we did the last Monday, which at this point was almost a week and a half earlier. I could remember doing this type of problem but I couldn't remember how to solve it. It was good we reviewed this because this type of problem is actual quite simple. You just have to divide the smallest mass by all the rest of the masses. So for this problem it was the washers mass divided by all the rest. For the anchor you are given the relative mass, so to find the mass you'll need to multiply that number (3.00) by the washers mass (1.74). That gets you the anchors mass.

This week I think I participated less then last week, but I think that was because there was less to participate in. I worked with my table mates on sheets given to us, and I calculated some numbers for Dr. Finnan, but I didn't take that much initiative to speak out answers with the class. I think a goal of mine will be to share more with the whole class, not just my table group.

But although I didn't participate as much as I could have, I still understood the material. The conversions made sense to me, along with (after reviewing it) the relative mass problems. What gave me some trouble was finding the molecular formula. I understood how to do it, the problem for me was remembering how to do it when I didn't have an example to follow. This was something I should have reviewed for more because I'm pretty sure I skipped a step when trying to solve it on the test. Because of this, I would rank my understanding as a 9 out of 10, because for the most part I understood the lessons this week, it was just that small piece that gave me trouble.

SG Chem 2 - Fourth Blog

This week in Chem 2 we were introduced to a new unit of measurement that is used often in chemistry. This new unit is called a mole and can represents 6.022 x 10^23 atoms/particles. We were also reminded of that fact that atoms combine in simple, whole-number ratios. We learned/re-learned  these two things separately but then later in the week we were able to bring both pieces of information together to solve certain problems that were given to us.

For example, on Monday we learned the basic concept of what a mole was. We completed a sheet that started us out with units of measurement that we already knew, such as a dozen eggs. Then, after solving problems with the dozen eggs the sheet applied what we knew about that to teach us how to calculate things with moles.

On Wednesday and Thursday we did a lab the involved combining zinc and chlorine. We combined the two elements then slowly evaporated the water (that was brought into the reaction through heating) away to get just the combination of zinc chlorine. By doing this we found that the mass ratio was approximately a 2:1 ratio. Each table, no matter how much zinc chloride they had, got the same ratio.

The zinc and the 3M HCl before combining

The Zinc and 3M HCl chemically reacting once combined

The chemical product of the combination of zinc and 3M HCl to form zinc chlorine
(Being put on ring stand to heat away any water)

The chemical product of zinc chloride when heated to get rid of the water

We took the information from the Monday worksheets and the results from the lab on Wednesday/Thursday to complete Unit 5 Worksheet 2 with sample containers. This sheet involved finding the amount of moles or atoms in a certain amount of a given element. For example it asked us how many moles of table sugar were in bottle two (sugar in bottle 2 = 118.6g). Because we know that 1 mole is the elements atomic mass (from the sheets on Monday) and that atoms/elements combine in whole number ratios (from our lab) we were able to calculate the amount of moles in each elements. We could even go farther and find the amount of atoms in the in the given element based on how many moles there were because 1 mole is 6.022 x 10^23.

I think this week I participated more in class. I took leading rolls in our lab that we did and I worked on asking my table mates for help when I didn't understand things. I also am trying to help my friends in the other chem 2 class (fifth hour) who are confused on things that I understand.

I think I definitely understand this unit and the things that we did in class a lot better than anything we did in unit four. That being said, I still need to work on the calculation problems. I understand the simple ones and I understand the concept of bringing down the unit so they can cancel out. What's hard for me is when the problem starts giving a lot of details with a lot of different units and lots of numbers. For example the last few questions that were on the homework sheet. They give a lot of detail and I'm unsure of how to know which ones to use and how to use them. Because of this I would rank my understanding of this week as an 8/10. 

SG Chem 2 Third Blog - 10/02/15

This week in Chem 2a we reviewed and finished up Unit 4 and then started learning Unit 5. On Monday and Tuesday we did a lot of white boarding, mainly consisting of two review sheets.

Review Board A

Review Board B

For many of the questions, the table groups were not able to come up with a single answer that we all understood as correct. For those questions, we decided to have class discussions to help us find and understand the right answers. For example, question three asked us to draw a mixture and a compound of CO2. The table group with board A drew the mix of CO2 as single carbon and oxygen particles (both monatomic), while the table group with board B drew the mixture as one carbon particle (monatomic) with two oxygen particles bonded together, creating a diatomic. Every other group had some variation of either board A or B. The question we had to figure out was, "Which one was correct?" This had rather a simple answer. After some discussion and help from Dr. J we found that oxygen was a diatomic and therefore board B was correct in having two oxygens combined together. 

Although this discussion was a brief one, it helped remind me that oxygen was diatomic and I was able to remember that on the test. The thing I forgot was that there was multiple elements that are diatomic so on the test I forgot to mark hydrogen as a diatomic. But now I understand what I did wrong and I'll be able to fix that mistake in the future.

Wednesday was our test day. I felt okay about it, but the hardest part for me was getting the right definitions of a mixture, compound, element, pure substance, etc. I studied them but I only memorized a definition I had written on a sheet, I didn't really understand the difference between them. This came to hurt me when taking the test because those specific definitions were not on the test and therefore I was rather confused and unsure of what was correct. 

On both Thursday and Friday we started up Unit 5. We started with a sheet called "Relative Mass" which dealt with finding the mass of different items (washers, hex nuts, and bolts) inside a container. We weighed the entire thing, box and all, then subtracted the mass of the box from each item to get the weight of the items by themselves. Then with that information we could find the mass of a single washer, hex nut, or bolt. By knowing the mass of each individual item we could then solve problems and answer questions about it, which is what we did. The main idea from this lab was that you can count the amount of items in a container (bag, box, etc.) by weighing. So far I think I'm going to like this unit better than Unit 4 mainly because the math makes sense to me.