Systems, Surroundings, and Ice

Today, as we walked through the door, we picked up two sheets from Mr. Lieberman's desk:
A brand new notes sheet and a worksheet for homework to go with it.

The lesson for the day was all about ENERGY and where it gets distributed during a reaction. The reaction itself is called a system, which is what we look at for data. The surroundings are made up of everything else in the environment outside the system.
-There are then three types of systems that we went over quickly
-Open system: can exchange matter AND energy with the surroundings (ex: open beaker)
-Closed system: can exchange ONLY energy with the surroundings while matter remains fixed (ex: sealed flask)
-Isolated system: can't exchange energy or matter with its surroundings (ex: thermos)

Then there's the exothermic and endothermic reactions. Exothermic is when energy flows OUT of a reaction due to temperature difference in the system and surrounding (negative q). Endothermic is when energy flows INTO a system from the surroundings (positive q).
*Qsurroundings = -Qsystem* They are equal and opposite for distribution of heat/energy

these are graphs like the ones we made in class:


(the activation energy is the energy to start the reaction)













After notes, we did a mini lab called Heat of Fusion of Ice with our partners.
Each group got a 100 ml beaker which we needed to mass before putting ice in it and massing it with the ice. My partner, Kathryn, then got warm water from Mr. Lieberman which measured to be about 71 ml with our data.
The initial water temperature was 50.6 degrees C and the final temperature with the water and melted ice was 22.6 degrees C.
After finishing the procedure, we were assigned to find the molar heat of fusion of ice using ratio. Before that, however, you need to determine the MOLES of ice that were melted.

(this will be due friday, while we have a webassign due tomorrow with a lab and another webassign due friday. whew..)
The next scribe will be...Rebecca N.