Finding Molecular Formulas (Dec.4/09)

(Sheryl Dris' post)
We began the class with going through and marking some of the Concentration homework.

Ex. 0.11mol of HCl in 2.0L of solution
M=0.11mol/2.0L
M=0.055mol/L

Following the mark-up, we continued with our Lab. The purpose of the lab was to find the concentration of the chloride (was it chloride?) by mixing it with the amount of water you chose to use. You had to complete the pre-lab in order to successfully complete it. It was simple yet fun! (Because we had to had it in, I don't have all the accurate measures in order to fill it onto this post!)
1)Measure the amount of chloride
2)Measure the amount of water
3)Combine and mix well until dissolved
4)See which one of the test tubes is the same
5)Record the data

Then we spend the rest of the class learning and going through one more section.
Finding Molecular Formulas
-You'll find it quite easy to do if you know the empirical Formula & the Molar Mass.If the empirical formula for a compound is CH2O and the molar mass is 60.0g/mol. Find the molecular formula.

Stock Solutions-are concentrated solutions from suppliers
12M-HCl
15M-HNO3
18M-H2So4

IN CLASS-Example
Michael wants to make 100mL of 0.20M HCl. What volume of 12.0M HCl should he use?
V1=? C1=12M V2=0.100L C2=0.20M
C1V1=C2V2
(12M)V=(0.100L)(0.20M)
V1=0.00167L
V1=1.67mL

*Unit2 Test will be Wednesday, December 9,2009! Good luck everyone!
Homework: Handout (review sheets)
-will be due on the day of the test