Week 14

"This week in Chem had just as much energy as the rest of them." To start off the week, we practiced more with LoL bar charts and got into the more complicated ones. We ended up not having another assessment on Tuesday, but just one at the end of the week. The main focus on some of the new bar charts was that a substance doesn't have to reach it's boiling point or freezing point in order to change phases. Instead, energy is taken from the thermal account and put into the phase account to allow it to change phases. For example, water could get to 100 degrees Celsius and not boil. Then we spoke briefly about our soap project, which will be done this upcoming week. All we have to do is get the supplies that we'll need for making the soap, and write up a brief report in Evernote. Before the assessment at the end of the week, we began the most complicated forms of LoL bar charts. With these problems, we had to determine if the problem dealt with thermal or phase energy. If it dealt with thermal, that's when we would use the specific heat equation. However, if the problem involved a phase change, we would have to use one of two new equations. If the problem involved a change from solid to liquid or liquid to solid, then it had to do with a heat of fusions. The equation we used was Q=m*change in Heat of fusion. On the other hand, if the problem had to deal with a change from liquid to gas or gas to liquid, it had to do with the heat of vaporization. The equation we used for this was Q=m*change in heat of vaporization. For water, the constants are 334 J/g for heat of fusion, and 2260 J/g for heat of vaporization. With these constants and whatever the problem gives you, you simply plug in what you have and solve for what you need to know! At the end of the week, we had our assessment. The assessment was based off of water freezing then melting, and using the different equations that we had. I feel very confident about it and anxiously await the results!