Chemistry Entry 5

Simple mass & mole problems.

Two problems I initially had difficulty with.

Our class began the week with reviewing our homework we had been assigned over the weekend. These problems consisted of calculations involving moles, various elements,  and the masses of assorted objects. Each problem varied in that you were given a specific amount of information, but each time the given information was divergent, so the unknowns had to be solved differently than usual. Sometimes more than enough information was given, so the reader had to be able to understand exactly what was being asked, and had to know exactly was was needed and what wasn't to solve the problem. Personally, I had a lot of difficulty in solving problems such as these, mainly because whenever I see something given that is unneeded, I fail to grasp the fact that the information is irrelevant to the question. This is partly due to me still learning about the material and that I am collecting more knowledge about how to solve these types of problems, but I also need to get over the mental roadblock I have in terms of problems like these. What really helped me begin to figure out how to tell which information was needed or not, was white boarding the homework as a class. I heard all of the input from my fellow peers and the various ways they went about solving the homework, and was happy to overhear that I wasn't the only student struggling with this. Solving out difficult problems such as these always seems to cause a light bulb to go off in my brain, and everything seems to click all it once. I would love to continue white boarding out problems as a class, as this learning style really seems to stimulate my learning abilities.

Solving for the empirical formula.

Finding the empirical AND molecular formula's.

Our next task was a worksheet involving Empirical and Molecular Formulas. I learned that the main difference between these two is that empirical means "based on experimental data", and the molecular formula is simply a formula giving the number of atoms of each of the elements present in one molecule of a specific compound. To solve one of these types of problems, you have to be given the grams of the specific elements, and have a periodic table present so as to find the atomic number of the given elements. Once located, for each element, you multiply the given mass of the element by 1 mole, which is then divided by the elements atomic number. Once you have solved that, you compare the numbers between the elements, and whichever is smallest, you divide all them by that amount. The approximated answer of this is simply the amount of the elements present in the empirical formula equation. If you're then instructed to find the molecular formula, all you have to do is add up the atomic numbers of the given elements, and then divide that number by the molar mass of the compound.

I'm a dingbat!!

The rest of the week consisted of a quick quiz and then studying for our test on Friday. The quiz seemed easy to me when I took it, but as it turns out, I made a really stupid which earned me the title of a "Ding Bat." I accidentally had multiplied an O, mistaking it for a 0 while it actually stood for oxygen. I somehow over looked this incident and had an interesting surprise when we were handed back the quizzes. In terms of the test, I felt a lot more comfortable and confident than I felt on the quiz, with nothing surprising me or striking me as being too difficult.