Week 3 Reflection

        This week, my SG Chemistry 2 class explored a variety of concepts that helped us to further expand our knowledge on the subject. On Monday and Tuesday, we completed and discussed a worksheet on Avogadro's Hypothesis. To start, we had to look at a picture of two containers of gas particles held at the same temperature, volume, and pressure and come up with a conclusion about the number of gas particles each container held. Because the pressure, temperature, and volume were all constant, we were able to conclude that each container must hold the same number of gas particles. This was the same conclusion Avogadro came to long ago, making it possible to deduce the formulas of compounds formed when these gases react. For the next part of the worksheet, we had to draw representations of hydrogen and oxygen particles and react them together to form water molecules with no gas left over. Since two volumes of hydrogen react with one volume of oxygen to form water, we knew we had to draw twice as many hydrogen particles as oxygen. Our final product had two molecules of hydrogen attached to one volume of oxygen and we called it H20. We followed this process to react different molecules together in the next problems, and these were our results:

For the final part of the worksheet, we learned that occasionally, one volume of gas can react with another volume of gas to produce two volumes of a gaseous product. Avogadro came to the conclusion that when this occurs, the molecules of some gaseous elements must contain two atoms as opposed to only one. In the following problems, we had to draw representations of multiple volumes reactions of gases, and these are the results we came up with: 

        On Wednesday, we completed an online activity to further our understanding of reactants and their products. After measuring the mass and volume of various substances before and after they were heated or burned, we were able to come up with three main ideas. The first idea is that some substances are composed of discrete amounts of two or more other substances. This means that elements react in defined proportions to create a product. Our second main idea is that the total mass of the products of a chemical reaction is exactly equal to the mass of the reactants. This means that mass is never created or destroyed during the process. Our final idea is that elements combine in specific, defined ratios during chemical reactions. All three of these concepts helped us to further comprehend the process of chemical reactions and the behaviors of the reactants throughout the procedure.
        On Friday, our class started a worksheet on compounds and different hypotheses. My group found the ratios of the element's masses easily, but had a hard time sketching the particle diagrams. We brainstormed our ideas until we came to a consensus and then drew our thoughts on the white board. As a class, we then discussed the first part of the worksheet and my group edited our answers after listening to what everyone else had to say.

Week 1&2 Reflection

        To begin our exploration of SG Chemistry 2, my class started out by reviewing many of the principle concepts learned throughout SG Chemistry 1. First, we completed three unit study guides which highlighted the main ideas in each unit. In the Unit 1 study guide, we defined mass as the amount of "stuff" an object contains and volume as the amount of space an object takes up. Generally, mass is measured in grams (g) or kilograms (kg) and volume is measured in centimeters cubed (cm^3) or milliliters (mL). We also recalled that centimeters cubed and milliliters are directly related; 1 cm^3 is equal to 1 mL. This conversion makes it simple to transition from one unit of volume to the other when necessary. A final idea we reviewed in the Unit 1 study guide was that the mass of an object divided by its volume is equal to the density of that object. Density can be referred to as the "compactness" of a substance and each individual substance has its own, unique level of "compactness". This means that by looking at an object's density, you can figure out what substance that object is made up of. After completing and discussing the Unit 1 study guide as a class, we moved on to Unit 2. While reviewing the Unit 2 study guide, we recalled that particle movement is a result of, or results in, changes in pressure, volume, or temperature. Any factor that affects the number of collisions in a substance impacts the pressure, so pressure, volume, and temperature are all interrelated As the temperature of a substance increases, the faster the particles move due to the addition of heat, causing more collisions between the particles, and an increase in pressure. This means that temperature and pressure are directly related. As the volume of a substance decreases, there is less room for the particles to move, causing an increase in the number of collisions between the particles, and resulting in an increase of pressure. In contrast to temperature and pressure, volume and pressure are inversely related. The final unit we reviewed was Unit 3, which we discussed as a group after our Unit 2 study guide. We recalled the concept of energy, which is defined as a "substance-like" quantity that can be stored and transferred in physical systems. Energy stored by particles is called thermal energy, energy stored due to particle arrangement is phase energy, and energy stored due to particle attractions is called chemical energy. We used these ideas of energy to help us review our energy bar charts and our heating/cooling curves. The review of Unit 1, Unit 2, and Unit 3 of SG Chemistry 1 was a helpful was to jog our memories of the significant concepts that will help us to better understand SG Chemistry 2.
        To start off our first unit of SG Chemistry 2, we had to begin by defining some key vocabulary words. In small groups, we worked together to clarify the meanings of molecules, atoms, particles, compounds, mixtures, pure substances, and elements. Attached is an image of the definitions we came up with:

At the end of the week, we also talked about the properties of matter. Matter has many properties; texture, shape, size, etc. However, the most important properties of matter are the ones that we can measure. In our small groups, we brainstormed the properties of matter that can be measured, and added to our list as the class shared their ideas. Here is the final list we came up with:

        Though our first two weeks of SG Chemistry 2 were mainly a review of SG Chemistry 1, we discussed many significant and prominent concepts of chemistry that will guide us to success during the course of the trimester.