LOL Graphs, Quantitative Energy, and Icy Hot

      This past week, we completed worksheets that covered quantitative energy problems and LOL graphs. These main ideas connect with each other because they all deal with energy being absorbed or lost. We also performed the Icy Hot lab, where we discovered what a heating curve looked like.

LOL Graphs We received two worksheets dealing with LOL graphs. We were given a situation such as "a cup of coffee cools as it sits on the table". Then we filled in the initial and final graph. E_{th represents the temperature. 1 bar stands for 0}°_{C, 2 bars stand for 25}°_{C, 3 bars stand for 60}°_{C, and 4 bars stand for 100}°_C. E_ph represents the phase, i.e., solid, liquid, or gas. 1 bar signifies a solid, 2 bars signifies a liquid, and 4 bars signifies a gas. For this particular problem, the initial E_{th is 4 bars, because it is stated that the cup of coffee is hot. The final} E_{th is 2 bars, because the cup of coffee should've cooled down to room temperature. The initial and final} E_{ph are both 2 bars, because the  coffee always stayed a liquid. After we filled in the graphs, we drew how many "bars" of energy was gained or lost. In this problem, 2 bars of energy was lost.}

cup of coffee problem

_{Quantitative Energy Two worksheets were given to us relating to quantitative energy. Using one of two formulas given to us, we solved each problem. The formulas were} Q=m*c*ΔT and Q=m*Hv or m*Hf.  _{We were also given energy constants. It takes 334 J/g to melt or freeze. It takes 2260 J/g to evaporate or condense. The heat capacity of solid water is 2.1 J/g*}°_{C. The heat capacity of liquid water is 4.18 J/g*}°_C. 

example of a quantitative energy problem

_{Icy Hot Lab In this lab we discovered what a heating curve looked like. We first attached a pressure sensor to the LabQuest interface. We then placed a temperature probe in a cup of ice and began stirring. When the temperature stopped dropping, we turned on the hot plate to high and immediately started Experiment on LoggerPro. A couple minutes after the water boiling, we turned the hot plate off. Afterwards, we printed out our heating curve. The results was a step formation.}

temperature probe stirring melted ice

our heating curve graph

      _{We came to know and understand the ideas this week by completing worksheets and labs. I still have a few questions about quantitative energy. My participation this week was good because I contributed to class discussion. I would rate my understanding of all the ideas this week an 8 because I'm still not sure about quantitative energy. I don't think I need to work on anything. My ideas have changed because I know more now than I did in the beginning of the week.}

PTVn Problems and Experiments

      Over this past week, we solved PTVn problems and reviewed for the exam on Monday. These main ideas connect with each other because PTVn problems was on the exam. 

PTVn Problems We received two worksheets relating to PTVn. We had to find the missing pressure, temperature, volume, or number of particles by using a table. The table had us fill in the initial, final, and effect of the PTVn. Occasionally, we were given temperature in Celsius. To convert Celsius to Kelvin, we added 273 to Celsius. The standard temperature is 273 K and the standard pressure is 1 atm, 760 mmHg, or 4.5 psi. After we filled out the table and found the missing PTVn, we created particles diagrams based off of our table.

Example of a PTVn problem

Exam Review Fourth hour started a whiteboard with everything we learned in Unit 2. We, however, thought they lacked a few key ideas and added on to what they had. The first key idea was the popcorn particles. This experiment taught us how gas particles moved and spread. The second key idea was the food dye experiment. This experiment taught us how liquid particles moved in hot and cold water. The third key idea was the PTVn tables, graphs, and labs. The PTVn labs and graphs taught us how pressure, temperature, volume, and number of particles related with each other. The PTVn tables taught us how to find missing variables. The final key idea was the "blowing up student" experiment. This experiment taught us how more gas particles causes expansion.

Whiteboard of the key ideas

      We came to know and understand the ideas this week by completing worksheets and doing whiteboard activities. I do not have any other questions relating to what we did last week. My participation this week was good because I contributed to the class discussion. I would rate my understanding of all the ideas this week a 10 because I am positive I know and understand everything we went over. I don't think I need to work on anything. My ideas have changed because I now know more than I did in the beginning of the week.