Sg Chemistry Blog of week 10/19

Sg Chem 2 reflection paper

Obi Ilozor 3rd hour

In this week in Sg chemistry class, we learned a lot about unit 6. I think that the concept of chapter 6 is conductivity and it has been confirmed all throughout the week. I think another big concept is electrical charge and that was proven when we took two days to carry out and white board a "tape" lab. In this tape lab, we stuck different objects to tape and other objects and ripped them apart. Then we saw if they attracted or repelled. We also did a lab where we put an electrical device to different substances and observed whether they conducted electricity. We could tell whether they conducted electricity or not by seeing if the light  on the device lit up. Overall, it was a pretty long week of new concepts that were hard to grasp at first, but as time went on, they became easier and easier to understand.

Our first lab was a tape lab when and we conducted it while our supervisor was gone. Fortunately, there were no problems. Since there are no current pictures of this lab, here is a picture of what is happening in the tape lab. There was a demonstration in our class as well about how balloons collect negative charges from objects and stick to other objects. The same thing happened in the tape lab. The concept learned from this lab is that electrons can transfer from object to object. That is how objects become charged.

These pictures below depict one of our most recent labs where we commuted to another supervisors lab and conducted an experiment. We put an electrical detective device to different solutions that lit up when it was touched. We found that metal solutions conducted electricity even if it was dissolved in a solution. Just like this molten metal shown below, even though it wasn't a conventional hard metal, it still conducted electricity. Solutions like liquid sulfur and hard sulfur and this solution that I have yet to identify, did not conduct electricity because the light on the device did not light up. Overall, this was my favorite lab but the solution names, that may pop up on the test, are the most confusing part.

The last lab that we actually conducted today was very peculiar. We hooked up a U-tube with graphite rods and electricity in a blue solution mixed with water and some metal alloy. We didn't finish the lab but results were evident. The graphite rod started transforming into something like rust, and its was reddish brown. We will observe the rest of the results on Monday but here is a picture of the lab with my colleague in it as well.

Overall, I believe this week was a really good and long introduction to chapter 6. 

Sg Chemistry 2 blog of week 10/12

Sg Chem 2 reflection paper

Obi Ilozor 3rd hour

In this week of Sg Chemistry, we took 2 assessments and reviewed what we learned in the previous week. The only new concept that we learned about was the molecular formula and empirical formula. We reviewed conversions from moles to number of atoms, grams to moles, grams to number of atoms, and vice versa for all of these examples. We learned about relative mass  We also learned about diatomic atoms where they double in mass in a gaseous state. Finally, we learned about element composition in a compound. On Friday, we began chapter 6 with a discussion about what keeps atoms together and how H2O was separated by the electrolosis contraption. 

First, we reviewed relative mass in a worksheet. We were told to look back to our old relative mass lab with washers, nails, and hexes. All of the materials were measured relative to the mass of the lightest object which was the washer. We did this lab to relate to all elements whose masses are relative to hydrogen which is the smallest element on the periodic table

On friday, we discussed how the electrolosis machine worked. No real answer was given to us yet but I theorize that what keeps compounds together are electrical bonds. It has something to do with magnetism and what particles attract others. When water is put into the elctrolosis machine, a current is sent through it. The electrical current somehow breaks the electrical bonds by maybe reversing an elements polarity but whatever it does, it breaks the compounds into two different elements and then separates them.

Second, we reviewed the conversions for moles, number of atoms, and mass. It is a fairly simple concept where if you want to convert something to another, you must put the unit that will cancel out on the bottom and the unit you want on the top. One important thing is that you cannot skip moles in the conversion of mass to number of atoms and vice-versa. You must go through the middle man. 

Third, we learned about the empirical formula and molecular formula. The empirical formula is the most simple formula of a compound such as H2O. A molecular formula is a variation of the empirical formula except it is not the most simple. Such a formula, relative to the one presented previously in the paragraph, could be H6O3. It just has to maintain the same ratio. You can calculate a lot of problems using these two formulas. The mass to mole conversion is used in these problems and then you are supposed to eyeball the ratio at which these elements combine at.

Fourth, we learned about percent composition of an element by mass. This was by far the easiest concept and it just used simple division to see how much of an element is in a compound. In the case of H20, oxygen has a 33 percent element composition in that compound. As you can see, it is very simple.

This chapter was a fun chapter and to me, it was much easier than chapter four. The hardest concept of this chapter was the mole to gram coversion factors and those weren't even that hard. Overall, I liked this chapter the most out of all of them so far. Thanks for reading

blog of week 10/5/15

Sg Chem 2 reflection paper

Obi Ilozor 3rd hour

These two weeks in Sg Chem 2, we did a fair amount of activities and labs. We entered unit 5 with a relative mass lab and a lot of worksheets. Our focus is learning about how atoms and elements interact in fixed ratios but also about the mole, which is a new a complicated term that we focused on. We were also starting to uncover the emperical rule. 

A mole is like a grouping of units. A dozen is twelve, a couple is two, but a mole is 6.022(10^23). Its a monumental number. If we had a mole of basket balls, it would definitely reach the moon and back several times. That is to tell you how small atoms are. The only way we can measure them on a feasible scale is to use this mole system. It is actually called Avagardo's number as well.

We also did activities like the relative mass labs. We did many worksheets of which we white-boarded. It proved that we can count by weighing and massing objects and substances before and after their reactions. This is key in the conversion process to find how many moles an object holds. 

    

As a class, we did a lab involving zinc and chloride. We put a fixed amount of zinc in a beaker, weighed it, and then added a fixed amount of hydrochloride. We let it sit for a day and then came back to it. It was then heated with a Bunson burner and massed after it cooled down. Here are the class results. My table in particular ran into a problem. Our burner during the reaction, stopped burning because the pipeline connected to the gas, fell off. It took quite a while to get the burner up and running again. That is one error that could have affected our results. By massing the end product and the before product, we can tell what happened during the reaction. From what we weigh, we can tell how many moles are in a substance and what it consists of. The most confusing part of this lab is the calculations that you have to make. With this lab came a worksheet that we completed. We were given problems that gave us the mass of a substance and we were to calculate how many moles this substance contained. It took me quite a while to get the hang of things and even still, the concept is hazy to me. 

This blog covers two weeks of material and this was from the previous week. We were still reviewing the law of multiple proportions and how atoms react with other atoms at fixed mass ratios. We did worksheets on this concept and we also had a test. There is no haziness in this concept.

In that same week(two weeks ago) we also learned how to find the ratios of atoms inside a compound just by weighing them. This is very useful because if we were to count manually, we wouldn't get anything done within our short life span. Weighing is pretty much the concept of what we have been doing so far. It is one of the most important parts of chemistry.