Tuesday, September 7, 2010

What's Wrong with a Little Change?

To start Chemistry class today, we discussed the Mixtures Lab (due tomorrow), and Mr. Lieberman asked if there were any questions. Question number 6 seemed to be confusing. Mr. Lieberman explained then to ignore it, or write the mass percent of each substance in the mixture.

Next, after turning in the Paper Clip worksheet from last week, we took notes on a powerpoint about chemical and physical propertieds and changes. Remember:
a Physical Propety is one that can be observed without a new substance being formed (ex. boiling point, melting point, texture, etc.).
a Chemical Property is a property that tells us how a substance would react in a given circumstance (ex. at what temperature does cinnabar split into mercury and oxygen?)
a Physical Change is a change that can be observed without the formation of a new substance, including change of phase. (ex. water freezing, boiling, a rock being smashed).
a Chemical Change is a change of a substance into a brand new substance. (ex. a bomb exploding, wood burning, banana ripening).

Finally, went over the prelab for "What Chemical Reactions?", which discusses properties and changes, and also determines that "corrosive," a property of HydroChloric acid, means damaging to skin and clothes, and then started the lab. Most of the groups did not get far because of limited time, but we did get to see some Chemical reactions. We will finish it tomorrow.

Sorry no pictures... I didn't get any good ones. The next scribe will be: Ben T

1 comment:

Mr. Lieberman said...

what are some other examples of physical/chemical changes?
What are the signs of a chemical reaction?