1. Introduction to the Mole and Math Concepts
Unit 6
Introduction to the Mole and Math Concepts

2. Formula Mass
The sum of the atomic masses of all of the atoms in a substance
Unit = amu(atomic mass unit)

3. Molar Mass
Molar mass (also called gram formula mass or gram atomic mass) is the mass of one mole of a substance
Units: g/mol

4. Percent Composition by Mass

5. Practice
a) Calculate the formula mass of Ca3(PO4)2 b) What is the percent composition of oxygen in this compound?

6. Percent Composition by Mass
What is the percent by mass of water in CaSO4●2 H2O?

7. Data Table: Heating of CaSO4 •2H2O
Mass of crucible
15.03 g
Mass of crucible and hydrate
17.90 g
Mass after 1st heating
17.25 g
Mass after 2nd heating
17.22 g
Mass after 3rd heating g

8. Mole Conversions!

9. Mole  Mass Conversions
Ex) 0.45 mol MgO  grams Ex) mol of Fe(OH)3  grams

10. Mass  moles
Ex) g H2O  moles Ex) 75.0 g N2O3  moles

11. Moles  Particles/atoms/molecules
How many molecules are in 1.00 mol H2O?
How many molecules are in 2.00 mol H2O?
How many molecules are in mol H2O?
How many atoms of nickel are in 1.00 mol?
How many atoms of nickel are in mol Ni?

12. Particles/atoms/molecules  moles
How many moles are in 6.02 x 1023 molecules H2O?
How many moles are in 3.55 x 1024 molecules of H2O?
If there are 2.19 x 1023 gold atoms, how many moles is this equal to?

13. 2 Steppers! How many molecules of CO2 are in 26.5 g CO2?
How many grams of Cu are in 3.45 x 1024 atoms of Cu?

14. Type 1
What is the empirical formula of a molecule containing 18.7% lithium, 16.3% carbon, and 65.0% oxygen?

15. Type 2
Find the molecular formula of a compound whose empirical formula is N2O5 and whose molar mass is g/mol.

16. Type 3
A compound has the following percent composition and molar mass:
39.9% carbon Molar Mass: 60.0 g/mol
6.7% hydrogen
53.4% oxygen
What is the molecular formula?

17. Warm-Up
1) Determine the molecular formula of a compound containing nitrogen and oxygen given the following:
Percentages by mass: 25.9% N and 74.1% O
Molecular mass: g/mol
2) What is the percent by mass of hydrogen in (NH4)3PO4?

18. Warm-Up- Period 4
#1) What is the percent by mass of hydrogen in (NH4)2S?
#2) A sample of barium iodide contains 35% barium by mass. Calculate the mass of IODINE in a 188 gram sample of barium iodide.
#3) What is the percent by mass of water in Fe(SCN)2● 7H2O?