1. Chapter 10.1 The Mole: A Measurement of Matter
The measurement of the amount of something is done by one of three different methods: by count, by mass, or by volume. 
Ex. Soda, grapes, gas
Practice problem 1 & 2 pg 289
Ex. 1 dozen = 12

2. Chapter 10 10.1 The Mole: A Measurement of Matter
Chemist use a unit that is a specified unit of particles. This unit is called the mole.
Ex. 1 dozen = 12
1 mole = 6.02 x representative particles
Avagadro’s number is 6.02 x 1023
A mole of any substance contains Avogadro’s number of representative particles, or 6.02 x 1023 representative particles.

3. Representative particles- refers to what is present in a substance; usually atoms, molecules, or formula units
When dealing with compounds representative particles are molecules.
When dealing with elements representative particles are atoms.

4. Converting number of particles to moles:
moles = representative particles X ___ _ 1 mole_________
6.02 x 1023 representative particles

5. Converting moles to number of particles
representative particles = moles x X 1023 representative particles
1 mole

6. Remember the atomic mass of an element is expressed in atomic mass units (amu)
Therefore 100 carbon atoms are 12 times heavier than 100 hydrogen atoms
The atomic mass of an element expressed in grams is the mass of a mole of the element.
Molar mass- The mass of a mole of an element.
Ex. Sulfur amu Molar Mass = 32.1g

7. The mass of a mole of a compound
To find the mass of a mole of a compound you must know the formula of the compound.
To calculate the molar mass of a compound, find the number of grams of each element in one mole of a compound. Then add the masses of the elements in the compound.
Ex. C6 H 1206

8. Chapter 10- 10.2 Mole-Mass and Mole Volume Relationships
Use the molar mass of an element or compound to convert between the mass of a substance and the mole of a substance. 
Mass(grams) = Number of moles x mass(grams)
1 mole or
Moles = mass(grams) x mole
Mass(grams) 

9. The Mole Volume Relationship
Avagadro’s hypothesis - states the equal volumes of gases at the same temperature and pressure contain equal number of particles.
Standard Temperature and Pressure (STP) - a temperature of 0 degrees Celsius, and pressure of kPa, or 1 atmosphere (atm)
At STP, 1 mol or 6.02 x representative particles, of any gas occupies a volume of 22.4 L.
Molar volume of a gas is the quantity 22.4 L.

10. Calculating Volume at STP
Volume of gas = moles of gas x 22.4 L
1 mol
Calculating Molar mass from Density
Grams = Grams x L
Mole L mole

11. 10.3 Percent Composition and Chemical Formulas
Percent composition- The relative amount of the elements in a compound
The percent by mass of an element in a compound, is the number of grams of the element divided by the mass in grams of the compound, multiplied by 100%
% mass of element = mass of element X
mass of compound

12. Percent Composition from the Chemical Formula
% mass = mass of element in 1 mol compound X 100%
Molar mass of compound

13. Empirical Formula
Empirical formula- gives the lowest whole number ratio of the atoms of the elements in a compound.
The empirical formula of a compound shows the smallest whole number ratio of the atoms in a compound.
Ex. Sample problem pg. 310

14. Molecular Formulas
The molecular formula of a compound is either the same as its experimentally determined empirical formula, or it is a simple whole number multiple of its empirical formula.  
Once the empirical formula is known, you can determine its molecular formula but you have to know the compounds molar mass
Sample problem pg.312