Mr. Quinn & Ms. Tom January 14, 2014

Aim: How can we solve empirical formulas where the smallest coefficient is not the greatest common factor?

Do Now:What is the greatest common factor of both 10 and 15?

Find the smallest whole-number ratio: 9:6:81

Solve the Empirical Formula:

C8H16

Solve the Empirical Formula:

Solve the Empirical Formula:

Al4O6

Mass data of Aluminum Oxide•Al: 53 %•O: 47 %

•Solution: If you come up with a 0.5 or similar, multiply by 2 to get back to a whole number

Checking in!•What is the empirical formula of a compound that has a carbon-to-hydrogen ratio of 2 to 6?

1. CH3

2. C2H6

3. C3H4. C6H2

Calculate the formula of barium oxide:•B: 31 %•O: 69 %

Calculate the empirical formula of this molecule:

Calculate the formula of formaldehyde:•C: 42.2 %•H: 6.8 %•O: 51 %

Checking in!

Given two formulas representing the same compound:Formula A: CH3

Formula B: C2H6

Which statement describes these formulas?1. Formulas A and B are both empirical.2. Formulas A and B are both molecular.3. Formula A is empirical, and formula B is molecular.4. Formula A is molecular, and formula B is empirical.

Your Turn!

Exit Ticket• Your calculations lead you to determine that the mole ratio of Cs to O

in cesium oxide is 2:1. What is the formula for cesium oxide?1. CsO2. CsO2

3. Cs2O4. Cs2O2