1.1 Moles and Molar Mass

Is it practical to count atoms?

No

Why is it not practical to count atoms?

They are too small

How to “count” atoms?

Weighing them or measuring them instead of actually counting

Atomic masses are measured in:

atomic mass units (amu)

Atomic mass unit is a ______ unit

Relative

Atomic mass unit is based on:

Carbon-12 isotope being assigned a mass of 12 grams per mole

A mole is a term used to describe:

a group of atoms containing 6.022×10^(23) items

Why do chemists use moles to discuss amounts of atoms?

The actual amount of atoms is such a large number that it is impractical

You can calculate the mass for one mole of a substance by:

referring to the periodic table to find the average atomic mass of each atom then adding up the total mass for the formula.

How to calculate molar mass:

1) List the atoms

2) Count the atoms

3) Find the mass of each atom from the periodic table

4) Multiply the number of atoms (#2) by the mass of each atom (#3)

5) Add together the values (#4)

Molar mass can be used as a conversion factor to convert between:

moles and grams

Molar mass is same/different for each sample

different

Avogadro’s number is a conversion factor to convert between:

Number of particles (molecules, atoms, formula units, ions) and moles