1. Meet the Mole.

2. Moles The mole is a unit of measurement.
The unit can be defined in multiple ways. (We’ll learn 3 today.)
In its simplest terms, it represents a specific number.
Dozen = what number?
Pair = what number?
Baker’s dozen = what number?
Mole = 6.02 x 1023
Atoms are SUBmicroscopic. In order to have an amount large enough with which to really interact, we need quite a few atoms.

3. Avogadro’s Number
6.02x1023
My pet mole is named Avogadro.

4. Defining the Mole
Counting
Weighing
Amount of Space Needed

5. Molar mass Example 6.5
Some questions simply test your understanding of the definitions.
Calculate the molar mass of sulfur dioxide, a gas produced when sulfur-containing fuels are burned.
SO2
S = g
O = 2(16.00 g)
Total = g/mol
Can also be expressed as 1 mol SO2 = g

6. Molar Mass Practice Problem 6.5
Polyvinyl chloride, called PVC, which is widely used for floor coverings (“vinyl”) as well as for plastic pipes in plumbing systems, is made form a molecule with the formula C2H3Cl. Calculate the molar mass of this substance.
62.49 g/mol

7. Unit Conversion Example 6.3
Most questions will require you to apply the definitions to convert from one unit to another.
Aluminum (Al), a metal with a high strength-to-weight ratio and a high resistance to corrosion, is often used for structures such as high-quality bicycle frames. Compute both the number of moles in a 10.0-g sample of aluminum.

8. Unit Conversion Example 6.4
A silicon chip used in an integrated circuit of a computer has a mass of 5.68 mg. How many silicon (Si) atoms are present in this chip? The average atomic mass for silicon is amu.

9. Unit Conversion Example
During cellular respiration, a cell releases 0.25 mol of O2 gas. What volume is needed to hold this gas?

10. Partner Practice Back together with 10 min left in class.
10-2 Practice Problems (1-3, 12-14, 17, 18, 23-25)

11. Calculate the number of formula units in a 45.0 gram sample of FeO.
Exit Question
Calculate the number of formula units in a 45.0 gram sample of FeO.

12. Problem-Based Learning Activity
Exit Question Groups

13. HIGHER LEVEL APPLICATIONS OF MOLE
Let’s make sure that we all understand how the particle vocabulary can complicate a problem.
Consider: Calculate the number of oxygen atoms in 3.5 g aluminum sulfate.
A few examples in your practice packet.

14. Choose a partner. Work is due at the end of the period.
MOLE THINK TAC TOE

15. Percent Composition
The relative amounts of each element in a compound are expressed in percent composition.
AKA: percent by mass of each element
% of element = grams of element X 100
grams of compound

16. Percent Composition Example 6.9
Carvone is a substance that occurs in two forms, both of which have the same molecular formula (C10H14O) and molar mass. One type of carvone give caraway seeds their characteristic smell; the other is responsible for the smell of spearmint oil. Compute the mass percent of each element in carvone.

17. Connecting Moles & Mass % to Chemical Formulas
Mass % is easily related to chemical formulas
The relationship of moles to chemical formulas requires a little more thought.
First, let’s learn two new vocabulary words.

18. Type of Chemical Formula: Empirical Formula
Empirical formula: lowest whole number ratio of the atoms of the elements in a compound
Ionic compounds are criss-crossed and then reduced. Ionic compound formulas are nearly always empirical formulas.
Covalent compounds are not always reduced formulas. (Ex. C6H12O6)
Therefore, an empirical formula doesn’t have to be the same as the actual molecular formula of the compound.

19. Empirical Formula
CH2O
Calculate the mass percent of each element.
C = 40%
H = 6.7%
O = 53.3%
Isn’t this the reduced formula for: C3H6O3, C4H8O4, C5H10O5, & C6H12O6
The mass percent of each of these compounds is the same.

20. Type of Chemical Formula: Molecular Formula
Molecular formula: actual formula for the compound which gives the composition of the molecule
Glucose shares an empirical formula with many compounds, but it has its molecular formula all to itself.
6(CH2O) = glucose

21. Applying the vocabulary
When an unknown compound is found, instruments can tell scientists the mass percent composition of the compound.
Calculations are required to convert that series of percentages into a chemical formula.
We start by converting to the empirical formula.
Situation: A white solid has been found on the floor of a government mailroom. Is it dangerous?
Step 1: Mass spectrometer analysis
40.9 % Carbon
4.58% Hydrogen
54.5% Oxygen
Molar mass of 180 grams/mole
Step 2: Convert % to formula with simple calculations

22. Calculating Empirical Formula
Use a simple rhyme!
% to gram
Gram to mole
Divide by the smallest
Multiply ‘til whole.
Situation: A white solid has been found on the floor of a government mailroom. Is it dangerous?
Mass spectrometer analysis
40.9 % Carbon
4.58% Hydrogen
54.5% Oxygen
Molar mass of 180 grams/mole

23. Empirical Formula Example 6.11
An oxide of aluminum is formed by the reaction of g of aluminum with g of oxygen. Calculate the empirical formula for this compound.
% to gram = IS DONE FOR YOU
Gram to mole = dimensional analysis
Let’s carry out the calculation on the board.

24. Empirical formula Example 6.13
A sample of lead arsenate, an insecticide used against the potato beetle, contains g of lead, g of hydrogen, g of arsenic, and g of oxygen. Calculate the empirical formula for lead arsenate.

25. Empirical Formula Example 6.14
The most common form of nylon is 63.68% carbon, 12.38% nitrogen, 9.80% hydrogen, and 14.4% oxygen. Calculate the empirical formula for nylon.

26. Calculating Molecular Formula
Molecular Formula= n(empirical formula)
(Remember 6(CH2O) = glucose)
We know how to calculate the empirical formula, but how do we know what number to multiply it by?
n= actual formula mass/molar mass of empirical

27. Molecular formula Example 6.15
A white powder is analyzed and found to have an empirical formula of P2O5. The compound has a molar mass of g/mol. What is the compound’s molecular formula?

28. Molecular formula Practice Problem 6.15
A compound used as an additive for gasoline to help percent engine knock shows the following percentage composition:
71.65% Cl
24.27% C
4.07% H
The molar mass is known to be g. Determine the empirical formula and the molecular formula for this compound.

29. Problem-based learning day 1: forensic chemist day 2: Assistant medical examiner
Mole Airlines

30. Warm up for Quiz
The final product in protein metabolism is urea. Urea contains 20.00% C, 6.73% H, 46.65% N, and 26.64% O. The molar mass of urea is 60.07g/mol. Calculate the empirical formula and molecular formula.

31. Problem-based learning day 1: forensic chemist day 2: Assistant medical examiner
Mole Airlines