# 3.4 Avagadro’s Number and the Mole

Section 3.4, which discusses Avagadro’s number and the mole, was covered early in the Chapter 2 material. The mole is a practical unit with which we can analyze and calculate quantities in units that are familiar to us, such as grams.

3.4 Grams to Moles Example Problem

Using Avagadro’s number, we can interconvert between masses, moles, and numbers of particles.

3.4 Grams to Atoms Example

We can also determine the percent by mass of each component in a compound.

3.4 Percent Mass Example

### 2 Responses to 3.4 Avagadro’s Number and the Mole

1. Kathryn Satkowski says:

did you want us to round the atomic weights to whole numbers for these types of problems, or use the exact atomic weight on the periodic table?

2. Jonathon Foreman says:

Instructors use the shortcut of whole numbers on occasion to make the point a bit more quickly. For your homework, labs and exams you should use the 4-5 SF atomic weights since most of the questions will have 3 SF in the given information. Carrying the extra SF for literature information prevents rounding errors.