1. Multi Step Mole Conversions

2. Arizona State Standards
Strand 5: Physical Science
Concept 4: Chemical Reactions
PO6: Solve problems involving such quantities as moles, mass, molecules, volume of a gas, and molarity using the mole concept and Avogadro’s number.

3. What are we learning today?
SWBAT use molar relationships to solve multistep conversion problems involving mass, volume of gas, and molecules using the mole concept and avogadro’s number.

4. How many moles of H2O are there in 36 grams of H2O?
REVIEW
How many moles of H2O are there in 36 grams of H2O?

5. Find the molar mass of H2O
Step-by-Step
Find the molar mass of H2O
Set up “railroad track” of dimmensional analysis
Convert from Mass to Moles using the Molar Mass (g/mol)
But how many liters of water vapor are there in 36 grams of H20?

6. Volume of 1 mole of gas 22.4 L per 1 mole of any gas at STP
Gases are mostly empty space so they ALL have the same volume despite different mass
22.4 L per 1 mole of any gas at STP
STP is Standard Temperature and Pressure
0°C and 1 atm

7. Molar Relationships
Liters
One mole of any substance produces 22.4 liters of gas at standard temperature and pressure (STP).
22.4 L/mol @ STP
Atoms/ Molecules/FUNs
Avogadro’s Number states that one mole of a substance is equal to 6.02*1023 representative parts of that substance
6.02*1023 rep. parts / mol
Grams
The molar mass of a substance indicates the mass per mole of a substance in grams.
(g/mol)

8. Mole Map GRAMS Mole Write this down! REP. PARTS LITERS Molar Mass
g/mol
22.4 L /
1 Mole
Avogadro's’ Number
Mole
REP. PARTS
LITERS
@ STP
6.02*1023 rep. parts/
1 mole

9. Build a bigger railroad track:
How many liters of water vapor are there in 36 grams of H20 at STP? X X
22.4 L H2O
1 mole =
44.8 L of H2O(g)
36 g H20
1 mole
18 g H2O

10. Build a bigger railroad track:
How many water molecules are there in 36 grams of H20?
36 g H20 X X
6.02*1023 molecules
1 mole
1 mole
18 g H2O =
1.20*1024 molecules of H2O

11. Putting it all together...
H2O
Moles
Liters:
(22.4 L / mol)
Grams
(18 g/mol)
Atoms
(6.02*1023 molecules/ mol)
36 Grams
(1 mol / 18 grams) = 2
44.8
1.20*1024
44.8 Liters
(1 mole/22.4 liters) =2 36
1.20*1024 Atoms
(1 mol/6.02*1023 atoms) = 2 moles

12. Let’s review some concepts
A helium balloon, on average, holds 14 liters of Helium gas. What would be the mass of helium in the balloon at STP?