Thursday, January 6, 2011

Mr. H started the day by showing us the answers to Chapter 8.2 reading sheet. Next, we moved on to review the blog by Neil. He reviewed the exothermic and endothermic reactions, but added entholpy, which is a form of chemical energy. Entholpy is basically the total energy or heat and is symbolized by a H. In an exothermic reaction, the heat is always on the product side and ΔH is a negative value. In an endothermic reaction, the heat is always on the reactant side and ΔH is a positive value.

Next we moved onto a demo. Mr.H started it off by asking people to feel the beaker, the wood, and the water to prove that this wasn't a trick. He started it off by putting water on the wood. Next, he put the beaker on top of the wood. He then mixed two compounds together to create an endothermic reaction. The mixture inside the beaker pulled the heat from the water and caused it to freeze onto the wood.

After that, we moved on to pg 5 of our packets. We worked on #1 which required us to figure out what kind of reaction it was. The answers are..

a.EX b.EN c.EX d.EN e.EX f.EN g.EN h.EX i.EN j.EX k.EX l.EX

Next, Mr. H showed us this concept on the board.

If A → B + 100J

...then 100J + B → A

...then 2A → 2B + 200J

...then 300J + 3B → 3A

After learning this we moved on to work on problem 2 on pg 5. It required us to find the missing value. The answers are..

a. -2408kJ b. 1204kJ c. 1652kJ d.2.70kJ e. -13.5kJ

Next, we moved onto page 4 #4. This problem was to be a sample problem for our TC3 lab. The answers are

a.Q= -27692.5

b. (Determine the Moles of ice that melted) 3.9111

c. 7.08kJ/mol

Finally, we finished our day by finishing up our TC2 and TC3 labs.