Notebook Setup AssignmentPage in Notebook The Mole Cornell Notes46 Moles to Particles Examples47 Particles to Moles Examples48 The Mole Review & Practice Problems 49

The Mole

Learning Objective Convert between moles and number of representative particles.

Measuring Matter How many objects am I asking for if I ask for 1 dozen? How many pieces of paper will I get if I ask for 1 ream? Regardless of the object the number that the unit represents (dozen, gross, ream) is always constant.

Measuring Matter Chemists need a way to count the number of atoms, molecules, or formula units. Atoms are small and there are SO many of them that it is impossible to count them directly. Because of this, scientists created a counting number called the mole.

The Mole The mole, abbreviated mol, is the SI base unit used to measure the amount of a substance. A mole of anything contains 6.02 x representative particles. A representative particle is any kind of particle, such as an atom, a molecule, a formula unit, an electron, or an ion.

The Mole The number 6.02 x is called Avogadro’s number. 1 mol = avogadro’s number of particles (just like a dozen = 12 of something)

Notebook Setup Write the conversion review and moles to particles examples 1 and 2 on page 47 of your notebook. Conversion Review How many roses are in 3.5 dozen roses? Moles to Particles Example 1 How many particles of sucrose are in 3.50 mol of sucrose? Moles to Particles Example 2 How many Zn atoms are in 2.50 mol of Zn?

Conversion Review How many roses are in 3.5 dozen roses? Conversion Factors: Problem setup: How can you tell if you used the wrong conversion factor?

Moles to Particles Example 1 How many particles of sucrose are in 3.50 mol of sucrose? Conversion factors: Problem setup:

Moles to Particles Example 2 How many Zn atoms are in 2.50 mol of Zn? Conversion factors: Problem setup:

Notebook Setup Write particles to moles examples 1 and 2 on page 48. Particles to Moles Example 1 How many moles of sucrose are in 2.11 x molecules of sucrose? Particles to Moles Example 2 How many moles of Zn are in 4.50 x atoms?

Particles to Moles Example 1 How many moles of sucrose are in 2.11 x molecules of sucrose? Conversion factors: Problem Setup:

Particles to Moles Example 2 How many moles of Zn are in 4.50 x atoms? Conversion factors: Problem setup:

Summary The mole is a unit used to count particles of matter indirectly. One mole of a pure substance contains Avogadro’s number of representative particles. Representative particles include atoms, ions, molecules, formula units, electrons, and other similar particles. One mole of carbon-12 atoms has a mass of exactly 12g. Conversion factors written from Avogadro’s relationship can be used to convert between moles and number of representative particles.