Chem Class- September 21, 2009

Today:
Mr. Doktor talked to us about our Unit Test. Ooooooooh scary!
If we had already completed the Lab, we were to work on our Lab write up as well as our review questions (In preparation for next class...Ah!). The people who either didn't finish their lab or didn't start their lab had the time to do that.

I'm sure you're probably wondering what the actual mass of salt is that can be dissolved in 200 mL of water. So, after everyone verified their results from the lab, Mr. Doktor told us just that: 11.5 g! We calculated the percent error by using this answer and the answer we were using. Remember how to calculate that?

Percent Error = (observed - theoretical/ theoretical) x 100.

I have to say, a lot of us were off by a lot!;)

Here's another youtube video. This one's on calculating percent error. One thing to note, however, is that they use the word 'actual' value. We learned in class that 'accepted' is probably the better word since there would still be error in the measurement.



Time to study now for that test!