1. 53I 95Am 22Ti75Re1D 2 Mastering Chemistry
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Due Tomorrow by 11:59PM

2. Empirical Formulae
The simplest whole number ratio of atoms in a molecule
Example: molecular formula = C6H12O2
empirical formula = C3H6O
Example: molecular formula = C16H32O2N4
empirical formula = C8H16ON2
Example: molecular formula = KMnO4
empirical formula = KMnO4

3. Calculating Empirical Formulae
What is the empirical formula of a compound that is made up of 10.95g C, 29.25g O, and 34.75g F?
Step 1: convert each mass to MOLES
Step 2: divide EACH by the smallest!!

4. Calculating Empirical Formulae
What is the empirical formula of a compound that is made up of 10.95g C, 29.25g O, and 34.75g F?
So we have 1 mol C, 2 mol O, and 2 mol F
Step 3: if each is a whole number, write the empirical formula
CO2F2

5. Calculating Empirical Formulae
What is the empirical formula of a compound that is made up of 32.79% Na, 13.02% Al, and 54.19% F?
Step 1: assume 100 g THEN convert each mass to MOLES
Step 2: divide EACH by the smallest!!

6. Calculating Empirical Formulae
What is the empirical formula of a compound that is made up of 32.79% Na, 13.02% Al, and 54.19% F?
So we have 3 mol Na, 1 mol Al, and 6 mol F
Step 3: if each is a whole number, write the empirical formula
Na3AlF6

7. Calculating Empirical Formulae
What is the empirical formula of a compound that is made up of 62.1% C, 5.21% H, 12.1% N, and 20.7% O?
Step 1: assume 100 g THEN convert each mass to MOLES
Step 2: divide EACH by the smallest!!

8. Calculating Empirical Formulae
What is the empirical formula of a compound that is made up of 62.1% C, 5.21% H, 12.1% N, and 20.7% O?
So we have 6 mol C, 6 mol H, 1 mol N, and 1.5 mol O
Step 3: if each is a whole number, write the empirical formula
Step 3a: multiply EACH ELEMENT by the smallest number that will make all of them whole numbers
C6H6NO1.5 O
1.5 x 2 = 3 C
6 x 2 = 12 H
6 x 2 = 12 N
1 x 2 = 2
C12H12N2O3

9. What is the empirical formula of a compound made up of 74. 01% C, 5
What is the empirical formula of a compound made up of 74.01% C, 5.23% H, and 20.76% O?
Step 1: assume 100 g THEN convert each mass to MOLES
Step 2: divide EACH by the smallest!!

10. What is the empirical formula of a compound made up of 74. 01% C, 5
What is the empirical formula of a compound made up of 74.01% C, 5.23% H, and 20.76% O?
So we have 4.75 mol C, 4 mol H, and 1 mol O
Step 3: If all of the subscripts are NOT whole numbers, then multiply EACH ELEMENT by the smallest number that will make all of them whole numbers
C4.75H4O
multiply EACH of the subscripts by 4! H
4 x 4 = 16 O
1 x 4 = 4 C
4.75 x 4 = 19
C19H16O4