Chemistry 2A Week 8 Review

     Welcome to the last blog of Chem 2A. This week in chemistry, we did a lot of experimenting. Along with having fun, we also learned a lot this week in Chemistry 2A.
     On Monday, we finished the nail lab. I thought it was really cool how the nails just got eaten away, they deteriorated. The main point to take away from this experiment is in the end, the ratio of moles of Fe, to moles of Cu, was 1 to 1.
     This is a photo of the nails before the reaction takes place. You can see the blueness of the copper 2 chloride surrounding the nails. Also, you can also see bubbles forming on the nails, hinting a reaction will occur.

 

  Also on Monday, we continued practice with balancing formulas. We completed Unit 7 Reaction Equations Worksheet 1. The biggest thing I took away from this worksheet is the even odd trick. If one side has a three, and the other side of the equation has a two, you just multiply them by each other. 2x3=6 and 3x2=6. Since atoms must be conserved, by multiplying the odd and the even, the cancel each other out, conserving the number of atoms on both sides. Something I didn't really understand was the fraction trick. I get how it ends, you multiply both side by the denominator. What I don't understand is how you figure out the fraction in the first place. I hope to clear that up next week.
     On Tuesday, we worked on word equations. The most important part of these is making sure you have everything on the correct side. The names of the compounds are given to you in the word problem, so those are not very hard to find. Always double check you have the right compound, especially for polyatomics. Nitrite is very different from Nitrate. Another item to keep in mind while doing these problems, is identifying what state the compound is in. For the most part, it's self explanatory. If it's solid sodium bicarbonate, then the sodium bicarbonate is a solid. The tricky one is if the problem says a solution of sodium bicarbonate, that means the sodium bicarbonate is aqueous. I understand this pretty well. The toughest part is setting it up correctly, and balancing it, but for the most part, I have a good understanding of  both.
     On Wednesday, we worked on the task chains. The task chains are a very helpful study tool. After sniffing some smelling salts and waking myself up, I got a good amount done in class. I have completed all of them, but the hardest one was the matching one. I still don't really understand it but I can just do the task chain again and again until I do.
     On Thursday, we conducted the Chemical Reaction Lab. This was a very interesting lab. I loved watching all the different types of reactions that happened, they were really neat.
     This was station 4. What happened here was hydrogen peroxide decomposed with yeast to form water and oxygen. This was a very cool reaction. The neatest thing was when we put a splint with the flame out, into the flask, the flame reignited. That is what's shown in the picture below.

 

     This was station 1. This was my favorite reaction. Solid magnesium combines with oxygen to form solid magnesium oxide. The coolest part of this reaction is that while the magnesium burned, ultra violet light was put off. Trust me when I say this, don't look into it. The light is beautiful but it burns.

     This picture shows the burned remains of the magnesium from the picture above. The ashes are purple because of the solution we put on them. The solution lets us know there is oxygen present because the ashes turned purple. 

 

      This is a picture from station 6. What I learned from this station is that chemical reactions give off heat. The vile itself got very hot because of the reaction happening inside. Also, enough Hydrogen gas was emitted for the Hydrogen bark to work. I find the Hydrogen bark very entertaining, and it shows the presence of Hydrogen

 

 

Overall, Thursday was a very entertaining day. I thought all the different reaction we saw were very cool. I don't understand how all of them happen, but they are cool nonetheless.

     On Friday, we worked on the Describing Chemical Reactions worksheet. In this worksheet, we balanced, and wrote word problems for the reactions we had experimented with on Thursday. This worksheet wasn't too hard. I understood most of the balancing. The hardest part was writing the word problems. You have to make sure you name the compounds correctly, distinguishing between molecular, ionic, and polyatomics. You also have to include the state the compound is in. It's like what we did on Tuesday, just backwards.

     Overall, this was a pretty good week. I understood most of what we were doing, I just need to study and practice it. I still need help with the fraction problems when balancing equations, so I hope to get that fixed. Other then that, I understand the gist of things. The atoms must be conserved when balancing chemical equations. When writing and solving word problems, one must make sure everything is on the proper side, include the state of the compound, and name them correctly. Also, burning things are fun.

 

 



Chemistry 2A Week 7 Review

      Week 7 of SG Chem 2A was all about naming. Ionic, or covalent, we learned how to name them this week.
     Monday, we started with the Naming Ionic Compounds worksheet. This worksheet walked us through naming Ionic Compounds. At first I was confused because I didn't even know what a cation or anion was. I understood what a cation and anion as after Dr. Finnan did some problems on the board. After hearing the problem spoken out-loud, I realized that every ionic compound has a metal. That realization led to me realizing that the metal in the ionic compound is the cation. If the metal is the cation, the other element in the compound, the nonmetal, must be the anion. As we completed the worksheet, I began to catch on and I now understand that a cation is the metal in the compound, and the anion is the nonmetal. For the mist part, this worksheet made sense to me. The main idea I took away from it was that in order to be in existence, the compounds must have a total charge of 0. So if that involves saying it's Fe (II) and not Fe(III) then it's really important to list those factors so we know the total charge is 0.
     Also on Monday, Dr. Finnan also showed us the oxidation of copper. Dr. Finnan held a burner next to copper that was already oxidized. The heat of the burner turned the copper touching the flame into pure copper. When Dr. Finnan removed the burner, the pure copper that was made was so hot, it reacted with the oxygen in the air, causing it to oxidize.

     On Tuesday, we practiced even more naming. We completed Unit 6 Worksheet 3. This worksheet was practice on naming ionic compounds. Something new introduced in this worksheet was creating the formula given the name. This wasn't very difficult. The elements are given in the name. However, the total charge of the compound must be 0. That was a rule I learned on Monday, so I applied it to the problems on the worksheet, and it worked and it made sense. The rule of the net charge being 0 is very important and it can change the formula of the compound. For example the ionic compound silver sulfide. From the name we know the compound involves Silver, Ag, and Sulfur, S. Sulfur has a charge of 2-. Silver has a charge of 1+. The formula for this compound isn't just AgS. That would mean the net charge is 1-. The name is Ag2S. If we have two silver atoms, both with a charge of 1+, then they cancel out the Sulfur atom with a charge of 2-.

     On Wednesday, we were introduced to Polyatomic Ions. Polyatomic ions are ions with more than two elements in them. We learned about polyatomic ions in the Polyatomic ions worksheet. Every polyatomic ion has a special name. There isn't really a trick to figuring them out, you just have to memorize them. At first it was difficult to understand these. I didn't really understand that every polyatomic ion has its own name. I was confused because I was trying to separate the polyatomic ion into the elements it consisted of, to name them separately. I now understand that the polyatomic ion in the compound can't be separated, it has its own specific name. I came to this realization by looking at the formulas for some polyatomic ions. Like BaSO4. The Ba represents Barium. The SO4, is a polyatomic ion with the name sulfate. All you have to do is match the polyatomic formula in the compound with its name. You can't separate the Oxygen form the Sulfur. Together, they create the polyatomic ion sulfate. So the full name of the compound BaSO4 is Barium Sulfate. A difficult component to naming polyatomic compounds is recognizing the polyatomic ion in the compound. There isn't really a trick to this. Once you realize the compound is polyatomic, you just have to check and see what polyatomic is in the compound by looking at the elements involved in the formula.

     On Thursday, we focused on naming Molecular Compounds. We completed the Naming Molecular Compounds worksheet. Molecular compounds are between nonmetals, they have covalent bonds. The important thing to remember with naming molecular compounds is that the elements get prefixes. For example, N2O4 is Dinitrogen tetraoxide. The di represents that there are two Nitrogen and the tetra represents there are 4 Oxygen. There are some rules for naming molecular compounds. The second element always ends in -ide, for example, oxide, fluoride, iodide. Second, if the first element listed in the compound has only one atom, it doesn't need the prefix mono, it is implied that the first element has only one atom if it doesn't have a prefix. For example, CO2 is not monocarbon dioxide, it is just Carbon dioxide. Thirdly, there are never two vowels. So it's not monooxide, it's just monoxide. You drop an o. It did not take very long for me o understand this. You just match the prefix with the number of atoms. The difficult part was remembering and recognizing that the prefixes only happen in molecular compounds. Any compound with a metal is not molecular, so it does not have the prefixes.

Reviewing on how to name compounds

On this whiteboard, it is important to note the atoms versus ions. The LiClO3 compound has five atoms. 1 Li, 1 Cl, and 3 O. However, there are only 2 ions. Li and ClO3. ClO3 is the polyatomic ion Chlorate, so you can't separate it into Cl and O3, they have to be together. You can separate Lithium because it is not part of the polyatomic ion.



Prefixes for molecular compounds

     On Friday we got the review guide for Unit 6. I understood what was on there and I hope I did well on Monday's test.

     This week in science was busy. At first, naming compounds was difficult for me. I didn't understand that the net charge had to be 0. I eventually figured that out and it became much easier. Sometimes you have to change the formula to make the net charge 0 by adding an atom. The difference between covalent and ionic bonds is the metal element in an ionic bond. Covalent bonds, or molecular compounds, get prefixes, and always end in -ide. Compounds with polyatomic ions, aren't that difficult. You just match the polyatomic ion with its name on the blue sheet Dr. Finnan gave us. Those wee the main ideas from week 7 and I look forward to week 8.