Tuesday, January 4, 2011

Mr. H began class by greeting us and explaining our agenda for the day. We immeditely were asked to get out our lab notebooks to write down the title and purpose of the TC2 Lab: Specific Heat of a Metal Lab. Purpose: To determine the specific heat of a sample of metal. After going over Kendall's blog we went to the back of the class room to begin the lab. Our lab groups split into two groups to complete to tasks. One group had to Prepare the Metal. Step 1: Measure the mass of a clean, dry, test tube. Record. Step 2: Empty metal (beads) into test tube. Step 3: Measure the mass of the test tube with the beads. Record. [Then subtract the mass of the test tube from the mass of the test tube with metal beads to find m the mass for your equation.] Step 4: Put the test tube into a hot water bath and heat water to about 80 degrees Celsius. The thermometer should be in the water (not the test tube.) Remember the 0th law. The other group had to Prepare the Water Calorimeter. Step 1: Obtain some cool/chilled water. Step 2: Place 50 mL into a dry styrofoam cup. After finishing our preparations we went back to the front of the classroom. Mr. H then reviewed with us our graphs from yesterday. He explained how after the system and surroundings met at thermal equilibrium their temperatures began to go down and would continue to go down indefinitely until the room temperature cooled and then the outdoor air would cool and then the universe would cool and we would all die. But that won't happen for billions of years so were alright. Next we went over Page 1 in our packets. First we were asked to state the zeroeth law of thermodynamics in our own words. I wrote two objects with a different temperature in contact with each other will transfer energy(heat) from high temp to low temp until they have the same temp. Then Alex explained what would happen if a hot piece of dishware was placed in a cold bowl of water. She said heat from the hot dishware would transfer to the cold water until they reached an equal temperature or equilibrium. Then we went over the chart at the bottom of page 1. We were given two situations ans asked to state the system and surroundings, the directional flow of heat, and what happened to the tempeatures (see picture left). Then we moved into the left side of our notebook. Mr. H went over an equation that pertains to our lab (see picture left). Then he went over exothermis process which pertains to our lab. Energy is lost from the system and transfered to the surroundings. The change of T is positive, the q of the surroundings is positive and the q of the system is negative. Next he went over endothermic process. The change of T is negative, the q of the surroundings is negative, and the q of the system is positive. Mr. H also noted through graphing that to being a chemical process there has to be a spark or actication. Finally we went back to the back of the room to finish the lab. We measured the temperatures of the hot water and the cold water then carefully put the metal into the cold water and measured the temperature until we got the highest temperature. Mr. H dismissed us. Our homework was Reading Webassign on 8.2.