Chemistry Entry 2

Kicking off this week, our class dove right into some new material, which I am still getting the hang of understanding. One of the first worksheets we started off with involved masses of elements in pairs of compounds (compound A & B), and we had to use the given information to suggest formulas that account for the written ratios. The first problem was simple enough, and it involved a certain mass of oxygen and carbon written in a ratio, in two different compounds. Using the information provided, we had to determine the value of the ratio in compounds A & B. To find this, I had to put the mass of oxygen over the mass of carbon, divide it out, and then round the answer to the nearest tenth or hundredth, depending on the answer. As we found for this particular problem, the ratio to compound B was twice as much as the ratio to compound A. Below our ratio computing, we were given two boxes side-by-side, labeled "Hypothesis 1" and "Hypothesis 2". In the hypothesis 1 box we were told that the mass of the carbon and oxygen had to have the same mass, and in 2 we were told that the oxygen atoms are heavier than the carbon atoms by the ration in compound A. To demonstrate this, we had boxes in which to draw particle drawings to represent both compounds. Once they were drawn, we had to write out an equation describing the drawing, which could be found by looking at the amount of the atoms for each element, and then writing out the element name as represented on the periodic table, and a subscript of the number just afterwards.



Originally this part confused me, but as I learned these drawings could be reasoned out by changing the ratio we previously found into an improper fraction. By doing this, the numerator represents the amount of oxygen atoms and the denominator represents the number of carbon. Throughout the worksheet, each single problem had a layout similar to this, yet they progressively got more challenging in terms of the given elements in a compound, and the varying ratios.  I would like to continue solving problems such as these as I am not 100% confident on them, and I would like to perfect my understanding by the time the test rolls around. In continuation of the worksheet described above, as a class we began to slowly understand the main idea behind solving these problems. The problem that eventually "clicked" with our class was comparing the compounds of iron and chlorine. Together we found the ratios and compared them, and reasoned that compound B has 1.5 more grams of chlorine then A does. Once we found this, the question we all asked ourselves was "so what?" I didn't see why this information mattered, or how it was applicable to writing out an equation comparing these two compounds. Slowly but surely, it began to dawn on us (with the help of Toby and Megan), that 1.5 was the amount multiplied by A's chlorine to get B's chlorine. As I'm writing this blog and looking over this worksheet, even still I am learning more and understanding this problem. Figuring out this problem as a class really helped to improve my understanding, so hopefully we will do more of that as the year progresses.

Another piece of information I found interesting and useful, was the history behind matter. It is crazy to imagine that scientists years and years ago forged their own ideas to describe matter, and used what they learned to apply to experiments and the world in general. As years passed however, new scientists with radical, unfamiliar ideas had multiple breakthroughs. These threatened the basis of chemistry and how matter was viewed for the "old school" chemists. In particular, Democritus suggesting the idea of atoms, Bernoulli theorizing that gases consists of small particles that are loosely packed in an empty volume of space, and Priestly's experiments with red mercury calx, leading to Lavoisier's discovery of oxygen. Fortunately these theories were proved and are now the footing of what chemists build off of today. This week started off a little bit overwhelming in terms of the new material and equations, but ended up enlightening me as well as providing me with a useful background of the "chemistry revolution" and those behind the fascinating discoveries.

Chemistry Entry 1

As I hadn't taken the first part of S/G Chemistry since the 2nd trimester of last year, the review packet handed out the first day was greatly appreciated. The packet consisted of an overview of the three major units we covered last year, which were: Matter, Energy and States of Matter part 1, and part 2. With our table members, our group had to whiteboard all information we could recall, and share it with the class as a way of us relearning the material, as well reminding other groups of what they had forgotten if it was not shown on their boards. The review packet handed out was a great helped as it jogged my memory on concepts I had since forgotten, as well as reinforced my understanding on a few ideas. Skimming over these basics really helped to jog my memory to get back into the chemistry groove, and build off of the given information.

Our first assignment as a class was the Classification of Matter worksheet, with the driving question of: How do atoms combine to make different types of matter? As we progressed, I learned that even the smallest chemical units of matter determine whether a substance can either be an element, compound, or mixture. Matter may look pure from the outside, but it ultimately depends upon what type of particles an object or substance is made of. I had a little trouble in atom classification, but as I continued through the problems, repetition assisted me. A few main ideas I took out of these specific problems is that a particle (a very small group of matter) can be a single atom, but a particle can also be a molecule. Also, I remembered that the difference between an atom and an element is that an element has multiple particles, while an atom has just one. Further, I learned that molecules differ from compounds because compounds have two or more types of atoms, while a molecule could be the same type of atom numerous times.

As a way to help us picture how various gases react together, our class went through a worksheet centered around the idea of Avogadro's Hypothesis. This theory states that the pressure of a gas is proportional to the Kelvin temperature, when the number of particles and volume are held constant. I was familiar with this idea from what I learned last year, but the scientist himself and the additional information we added to this hypothesis was entirely new to me. As a visual learner, solving the problems on the worksheet using pictures and shapes was a huge help. It was very clear on how the the gases to-be-combined had their own unique structure, and once merged it was easy to see how they ended up in that state. In addition to Avogadro's hypothesis, early chemists also learned that one volume of two separate gases can combine and produce two volumes of gaseous product. This only occurs (through Avogadro's reasoning) if the molecules of the gaseous elements contain two atoms. An example of this that we preformed on our worksheet was the combination of hydrogen and chlorine. Both hydrogen and chlorine already contain two atoms bonded together, so it was no surprise to me that the hydrogen chloride created had two volumes of gaseous product in the outcome.

Vdeo from class: Gases and How They Combine  Skyline Periodic Table

This first week was a great help in stimulating my brain to remember everything I had forgotten from last year, as well as added new concepts to build off of. I still need to work on reinforcing my understanding of how gases combine and what variables cause them to do so, but I have a feeling I won't have too much of an issue soon, as we go over the concepts in class consistently. Personally I'm a huge fan of white boarding out problems and then sharing our answers with everyone, mainly because of my preference of visual learning, but constantly reviewing problems in this matter are of a huge help to me. I am intrigued as to what this next week of chemistry holds for our 5th hour.