Popcorn Lab

Popcorn Lab on Prezi

Unknown/Mole Lab

Mole Lab!


Tenchita, Timmy, Serena and I had a lot of fun in this lab just because we felt like really scientists. We were told to figure out the atomic mass given only the number of moles. We weighed each cup to find out the grams and then took the number of grams divided by the number of moles to get the atomic mass. Given the atomic mass we find out what the element was. 


Avogrado's number - (6.0221367 x 10^23).



Data
Sample.             Number of moles.        Grams.           Atomic mass.      Element
     A.                            .163                     6.53             40.061                 Ca
     B.                            .910                    24.51            26.934                  Al
    C.                             .160                     9.44             59                       CO
     D.                            .258                    53.90           208.9                     Bi
     E.                            .220                    14.26           64.81                    Zn 
     F.                             .756                    49.26           65.158                 Zn
     G.                            .492                     28.66           58.25                  Ni
     H.                             .430                    89.16           207.349              Pb
     I.                               .381                    21.28            55.85                Fe
     J.                             .259                     30.70           118.53               Sn

Hydrate Lab

Although I wasn't here for the lab Timmy, Serena, and Tenchita are nice enough to let me use their data to do a write up about this experiment. They chose to do the experiment involving epsom salt. They put the epsom salt in a test tube and weighed it before any other experimentation. The weight before heating the salt was 4.07 grams. They then heated the salt (telling me that Kandace almost killed them a couple times with matches and the gas). While heating the tablets turned white which they then let cool. After letting the flaming salt cool they weighed it after, noting that it weighed 3.66 grams. They then added water, learning that the crystals turned back to blue.
By subtracting the weight after heating from the weight before heating, we discovered that the crystal only had about 10% water. This is different from the expected percentage because of crystals that got stuck in the tube and crystals that were still blue.
The formula for the crystals is CuSO4 5H20. After multiplying the total CuSO4 mass by 5 parts water, I learned that the total water mass is 90 grams while the total mass was 249.6 grams. After dividing the 90 grams by the 249.6 grams, we discovered that the expected mass was 36%.

Calculations

Moles!
No not the animals, more like the number of moles in an element how the amount of moles needed for a compound.
One mole equals 6.02x10^23 atoms.
So, how do you find how many grams per mole an element has? For example, the element Bromine has a mass of approximately 79.9 so it is 79.9 grams/mol. Now, looking at a compound such as K2O. Potassium has a mass of 39.098 and Oxygen has a mass of 15.9994. Since there are two potassium atoms, we have to multiply the 39.098 by 2 and then add the 15.9994. The final answer is 94.196 K2O. This means there are two potassium atoms for every one oxygen atom, but I'll get into that a little bit later.
Looking at a more complex compound such as C14H18N2O5, it's easier to find the measurement of moles in the compound. First you must calculate the grams per mole, which turns out to be 294. Then you take the mass of the smallest element, which is 225 grams. Divide the 225 by the 294 to get the answer. C14H18N2O5 is .765 of a mole.

Percent of Composition
Let's find the percent of composition of Carbon in an artificial sweetener. The compound is C5H8NO4. To get the percent of composition one has to divide the mass of the total Carbon by the total weight of the compound. Carbon has a 12.0107 mass, but there are 5 atoms of Carbon, so the total mass is 60.055. The total weight of the sweetener is 146.1212. 60.055/146.1212 is approximately 41%. So, Carbon is 41% of the artificial sweetener compound.

The Empirical Formula
The Empirical Formula helps a scientist (or student) determine the compound that is put in front of them based on the given weights. For example, when 2.34 grams of Nitrogen and 5.34 grams of Oxygen are put in front of you, by dividing by the weight we find out that there are .167 moles of Nitrogen and .333 moles of Oxygen. Take the .167 and divide it by .167(the least amount of moles) and do the same for .333 which rounds out to 1 to 2. So, the ratio is one to two. But, that could mean that the compound is NO2 or N2O4. The fact that the compound weighed 93grams was given. Through multiplication, it is found that the compound is N2O4 (Dinitrogren Tetroxide)

Naming Molecular Compounds and Types of Chemical Bonds

Naming Molecular Compounds and Types of Chemical Bonding on Prezi

Compound Names and Formulas

Naming Compounds is fairly easy when Mr. Ludwig gives you a handy dandy chart to look off of. Basically, all you have to do is find the formula and match it with the name.
For example:
NaF
Na= Sodium
F=Flourine
So the compound name is Sodium Flouride. (ions end in -ide)

Things can soon get more complicated like with the compound
Mn(NO3)3
The outside 3, goes to the top of the Mn, so it's Mn3. Mn3 = Manganese(II)
The only formula left is NO3 which is Phophate.
This equation is Manganese(II) Phosphate.

Now, when turning names into formulas the same rule applies: LOOK AT THE CHART!
The name potassium flouride is easily turned into KF after looking at the chart, but the names can get more difficult. When looking at Ammonium Sulfate, we see that they charge of the ions don't equal. Ammonium is NH4+, while sulfate is SO4^2. The positive 2 charge is moved over to the ammonium in order for the equations to equal out. This turns the equation into (NH4)2SO4.
These basic principles continue to apply as we went through the 24 problems on the paper.

Why is Gold our Currency?

While listening to the podcast and looking at the periodic table I realized there are numerous reasons why Gold is our currency and why other elements on the table would not work.

Gold Coins

Hydrogen, and Helium through Rn would leak away because they are a gas.

Lithium wouldn't work because it is very flammable, so flammable in fact that it has the possibility to burn through concrete.

A lot of other elements on the table are reactive, meaning they can combine with other elements or corrode. 

The actinides wouldn't work because they are extremely radioactive. 

Silicon(a key ingredient in sand) is too light and way too common, as well as copper. 

Osmium on the other hand is found in meteorites, meaning they are way too rare.
Silver has a different issue. It tarnishes easily. Once the silver tarnishes you can wipe away the tarnish but that is also wiping away part of the silver at the same time, therefore losing some of it's value.
Paladium and Rodium didn't appear til after our currency was created, meaning they couldn't be suggested as our currency.
Platinum has an extremely high melting point, making it too difficult to mold into the shapes of coins or other shapes. Also, platinum looks like numerous other metals, meaning the currency could be easily replicated.
So, this means gold is our only choice. It never corrodes, it's solid, it wont kill you because it's not radioactive, it's rare but not too rare, it's easy to melt, it's obtainable, and most of all it's testable. There is a simple test involving a pumice, a black stone, and a little bit of acid. The smudge left determines the purity of the gold, but does not ruin the metal. This test dates back to Ancient Greece.
Overall I think Gold was the smart choice for our currency.

(Here is the podcast that I used as the basis of this blog, borrowed from Mr. Ludwig who got it from npr)