The Mole

We have talked about the mole for about 2 weeks so far. First we talked about what a mole actually is.
A mole is pretty much a huge number. It is 6.02x10^23. It was invented by Amadeo Avogardo. The number is always the same because a mole is a mole so the number never changes if you work with moles. Since the number is always the same the mass can differ. The molar mass is also shown on the periodic table. It is shown in grams. There are weird numbers above the atom like 15.9994 (O). This tells you how many grams of the particular atom equal one mole. There are also 2 conversion factors: 6.02x10^23 divided by 1mole         and        1 mole divided by 6.02x10^23. With these conversion factors you can see how many grams you need.
After we've figured out all that we've talked about how you covert from grams to mole and from mole to grams. It took us quite a while but then everybody figured it out.
If you know how many grams you have you need to divide the grams by the number of the atom that is shown on the periodic table. Then you know how many moles this amount has. If you know how many moles you have you have to multiply by the number of the atom that is said on the periodic table in order to find out how many grams this amount of mole is. If you have a compound of elements like NaF and you want to know how many grams there are in a certain amount of moles the first step you have to do is that you have to add both the number of Na and the number of F and then you can work the way I just described.
We also talked about how to find out how many percent of one atom there are in a compound. Let me give you an example. You have C5H8NO4 and you want to know how many percent of the compound is C. Then you take the mass of C5 and you divide it by the mass of the entire compound and then you multiply it by 100 in order to find out the percentage. In general you take the mass of the atom of which you want to find out the percentage (if there are like 5 of these atoms you take the number times 5) and then you divide it by the mass of the whole compound. That's the way to find out the percentage of an atom in a compound.
After that we did a little experiment about how to convert a recipe. We had the numbers of moles and grams and particles and we had to find out how much you need of everything. But for luck the conversion factors were said on the back of the paper so it wasn't too hard to figure it out.
Then there is something called empirical formula. the empirical formula shows you the ratio of how many atoms you need in a compound. There is also the molecular formula. This tells you, if you have figured out the ratio of atoms in a compound, how many of these atoms you need because you know the grams of the compound but it might differ from the actual mass of the compound. You can see that if you add the number of the compound you have and you subtract the number you got from the empirical number and then you know whether or not you need twice as much of this compound or only the half or more or less.
The last experiment we've done was a Popcorn experiment. Since I have already explained how to figure out how you can find out the percentage, we had to do it. We used a beaker, oil, cover, and kernels to make popcorn. First we put some oil in the baker and then we weighted it. Then added the kernels and weighted it again.  Then we put the cover on it. After this we put some holes in the cover. Then we heated the beaker with the kernels and the oil in it. After the kernels have pooped and turned into popcorn we waited until the beaker cooled down. Then we weighed the beaker with everything again.  Then we weighted it again too see how much water was lost. After the heating it lost 1.3 grams. This is how much water the kernels lost during the reaction. Then we took the difference between the grams of the beaker with oil and kernels and the cover and the beaker with the cover, but without kernels(3.3 grams). Then you divide the smaller mass (1.3grams) by the bigger mass (3.3grams) and divide it by 100 in orer to find out how many percent (like in this case) the popcorn lost(39%).

Conductivit lab

This week we did some experiments about ions.
We made 8 different solutions that you can see in the following picture.

 

We take a battery and a small light so we can see whether or not the solutions conduct current. 

The solutions are put in small glasses.

How you can see on the picture above all of the solutions conduct current. 

Some solutions conduct less current than others because if an atom is solved in water it can give or gain more easily electrons than if it is solid. Like NatriumChlorid Natrium it gives an electron because it has only one electron on the outer space and Chlorid gains one electron because in has seven on the outer space. Basically you can say that all the atoms that have 3 or less electrons on the outer space give their electrons in order to have a filled outer space and all the atoms that have 5 and more gain electrons until their outer space is filled. However, if an atom needs to give or gain 3 electrons it is kind of hard because the electron still wants to own the third electron and the other atom wants to get the electron. So both electrons "pull" that electron and then you have a positive or a negative charge. If an atom has 4 electrons on the outer space it it very hard to gain or give all the electrons because then there is a positive or negative charge, too. 

For me the unit about ions will not be very hard because that was one of the first things we've learned in Germany. In Germany we are still working with ions so i don't have problems with it, also because it is one of the most important themes in chemistry I think.

The next step you could do to improve your knowing about ions is to make some compounds (theoretically) and write down which atom gains electrons and which atom gives electrons. Then you should also write down if the atom is charged positively or negatively.

By Andre Simons

Light Spectra

This week we learned what light is.
Light is formed out of the energy from an electron.
You get this energy when an electron of one atom changes its energy levels by jumping from one level to the other and then back. During this process the electron contains energy which it absorbs when it goes back to its original level. This energy is called a "photon". A photon is light.
The main character of light is its wavelength. Because the energy that the electron transports differs we can see different colors.
This is why a shorter wavelength is a darker color and a higher wavelength is a lighter color. Ultraviolet which has much more energy than for instance infra red. This is why it is dangerous to go to a tanning bed. Because ultraviolet has a lot of energy is can enter your cell nucleus and cause cancer.
The frequency of the wavelength is also important The frequency says how fast the amplitude of one wave is. The unit of the frequency is Hertz. It is defined as: Times of oscillation divided by the time it takes.
On the following picture you can see some of the colors we can see. We took different elements (gases) and looked through a spectroscope and then we saw the following colors:

I learned this week that you can separate the colors we see by watching through a spectroscope and i learned that the amplitude and the wavelength is an important role in light. Some things I have learned in Germany, too.
I liked the experiments we made a lot because they were fun and it is kind of exciting what gases are made up of.
By Andre Simons

Separation Techniques

We made also another experiment. We took sand, marble hips and some iron. In order to separate iron we need a magnet and a small bag. Then we put the magnet into the bag and go over these chemicals. You can see that iron is magnetic and it is seperated from the two other chemicals.
We separate the sand from the marble chips by using a filter screen. Then we have all three chemicals separated which we mixed at the beginning of the experiment.

Chemistry Separation Techniques

Chromotorgaphy
We take some pens (red, green, black, ...) and draw on a filter paper. Then we fill some water in a petrie dash. After that we make a small hole in the filter paper and put an other small paper through the hole. Then we can see that for instance red is made out of more than one color.