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%).
