Part 2: Empirical Formulas

In Chemistry we have been working on a couple different important concepts. I recently posted Part 1 on my blog which was a blog post about percent compositions which is a helpful skill on it's own. But! The next step is Empirical Formulas. And to be honest this is one of the most fun things I have done in Chemistry. Above is a flow chart that I made to explain how to solve an empirical formula from percent compositions. On the left side the chart describes the basic steps towards solving empirical formulas, and on the right side I work an example problem to further explain exactly how this process works! This will also be posted on my Pinterest Board which can be found here:

Sierra's Pinterest Board of Awesomeness!

:)

Shameless Plug...

So...about a week ago I came up with the idea to start a board on pinterest to include the things I have been learning in Chemistry. Right now we have been focusing a lot on the mole and how it relates with percent composition and formulas. I at first thought that I would only include that information on my Pinterest Board, but I have enjoyed it so much that I think I will continue to add to the board no matter what we are studying in Chemistry. I plan to pin some of my blog posts here...but also other things I make and find that relates to what we are studying. So here you go:

http://pinterest.com/sierra135/the-mole-chemistry/

This is the link to my Mole/Chemistry in general board on Pinterest! I hope to keep this board up for the rest of the year, and who knows? Maybe beyond ;) and add stuff that is helpful in gaining a greater understanding of what we are studying!

Enjoy!

Part 1: Percent Composition

Our Friend! The Periodic Table!

Over the past few weeks we have been focusing on some pretty big ideas. Above is a scanned image of the notes I took over three big concepts that we have been working on:
1. Percent Composition
2. Empirical Formulas
3. Molecular Formulas

First we worked on Percent Composition which is probably my favorite thing we have been doing. It takes some help from our friend the periodic table. Above on the left side of the scanned image of my notes you can see the formulas C5H8NO4. And you can see the rows of numbers below each letter. What does this mean? Well to find percent composition, we first need to look at the periodic table. C is the symbol for Carbon and when we look we see that the atomic mass is 12.011. In our formula there 5 Carbons. Sooooo...12x5 is 60. Then we do the same thing for the other symbols...Hydrogen has an atomic mass of 1.0079 (Hint: I round the numbers when I add them) so, 1x8 is 8. Then we move on to Nitrogen and Oxygen. At the end of it all, as you can see above, after we add together all our numbers we end up with 146. This is an important number because we need it to find the percent compositions of each Element in this formula. In the scanned image above I found the percent composition of Carbon in this formula. How did I do this? I divided the total mass of Carbon in this formula by the total mass of all of the elements. Which looks something like this: 60/146. Which is... .4109 and so on. Moving the decimal over we find that our percent composition of Carbon in this formula is 41.1%! This can be applied to any of the elements in the formula. For example the percent composition of Oxygen in the formula is 64/146 which comes out to .4383...43.8%!

Percent Composition is probably the most simple thing (to me anyway) that we have been working on. And I have really enjoyed working with problems to find Percent Composition!

Types of Reactions Lab

This is the Prezi I created to talk about the process involved in the types of reactions lab and the information I gathered while doing the lab!

Types of Chemical Bonds

We have been talking a lot about Chemical Bonds in Chemistry...


Ionic Bond:
First we started by identifying ionic compounds, which wasn't too hard. You just have to look for a compound that includes a metal and a nonmetal. So identifying them aren't very hard. This sheet to the left is a worksheet we did to identify compounds that are either ionic, covalent, or both. After we learned about ionic bonds we moved on to covalent bonds.





Covalent Compounds:
Below on the far left is a worksheet we did in Chemistry to work on naming covalent compounds. You can see the list I wrote in. It shows all of the prefixes involved in naming the compounds. For example on number 1 you can see that it says CO2. C is the element Carbon and O is the element Oxygen. When they are together they are Carbon Dioxide because there is a 2 and the prefix for 2 is Di! Another thing that helped in naming these compounds was the chart that Mr. Ludwig gave us. It is below on the right side and was really helpful in figuring out how to go about naming a compound if I got stuck on a really hard one.

Chemical Names and Formulas

One of the major things we have been working on this quarter is writing out the formulas for compounds and being able to identify the name of compound by it's formula. I had a lot of trouble with this at first, but once i got the hang of it it became really easy and actually pretty fun!

This first sheet is an activity that we did to help us with naming compounds and writing out formulas. This helped me a lot. There is a lot of confusion when it comes to some of them at first but it really helped to use a  "cheat sheet" Mr. Ludwig gave us that basically listed some different elements and their number of protons or electrons and how they can combine to make a compound! 

Below is a test I took in Chemistry that shows my ability in naming and identifying names and formulas of compounds. I only missed one question on this test!

Ionic Compound Lab

Ionic Compound Lab:

Pre-Lab:
1. Read the entire procedure. Identify the variables. List any conditions that must be kept constant.
-In this experiment I think that the amount of Magnesium must be kept constant. And we must make sure we get a correct mass value before we burn the Magnesium and a correct mass after it is burnt. 
2. Write the electron configuration of the magnesium atom.
-The electron configuration is 1s2 2s2 2p6 3s2
     a. Based on this configuration, will magnesium lose or gain electrons to become a magnesium ion?
I think that magnesium will lose electrons to become a magnesium ion.
     b. Write the electron configuration of the magnesium ion.
-The electron configuration of the magnesium ion is 1s2 2s2 2p6.
     c. The magnesium ion has an electron configuration like that of which noble gas?
-The magnesium ion has an electron configuration like that of Neon.
3. Repeat question 2 for oxygen and nitrogen.
-The electron configuration of the oxygen atom is 1s2 2s2 2p4.
-I think that Oxygen will gain electrons to a  oxygen ion because it has six valence electrons.                  - The electron configuration of the oxygen ion is 1s2 2s2 2p6.
-The electron configuration of the Nitrogen atom is 1s2 2s2 2p3.
4. Prepare your data table.
5. In your data table, which mass values will be measured directly? Which mass values will be calculated?
-The mass values that will be measured directly are the masses of the empty crucible, the mass of the the crucible with the Magnesium in it before heat, and then the mass of the the crucible with Magnesium in it after heat. The masses that will be calculated are the mass of the Magnesium before heat and then the mass of the the Magnesium Product at the end of the experiment. 
6. Explain what must be done to calculate each mass value that is not measure directly. 
-To calculate the masses that aren't measure directly we will have to subtract the mass of the empty crucible from the mass of the crucible and the magnesium. And then subtract the mass of the empty crucible from the mass of the crucible and magnesium after heat. 

What we used:

Magnesium Ribbon
Crucible
Ring stand and ring
Clay Triangle
Laboratory Burner
Stirring Rod
Crucible Tongs
Centigram Tongs
Centigram Balance
10-mL Beaker
Distilled Water
Conductivity Tester

Procedure:
1. We set up our area. We put the ring on the ring stand and placed the clay triangle on the ring.
2. We measured out the mass of the crucible and wrote it down.
3. We used a ruler to measure out 25 cm of magnesium ribbon. And then rolled the Magnesium into a ball. We placed the ball into the crucible and recorded the mass of the crucible and Magnesium.
4. We put the crucible on the clay ring, and turned on the gas for the burner.
5. Mr. Ludwig lit the flame, and we placed the crucible over the flame.
6. We waited for the Magnesium to burn.
7. After it had burned we turned off the flame and left the Magnesium to cool.
8. After it had cooled we measured the mass of the crucible and Magnesium product and wrote it down.
9. Then we dumped the Magnesium Product into a beaker with 20 mL of distilled water.
10. We then tested the Conductivity of the solution and recorded it.

Analyze and Conclude:

Click Here! For my Conclusion!