# Question #5a7e3

May 11, 2016

Mass is measured in grams. Scales are calibrated to read a mass, but not moles. The mass of an element is relative to the lightest element on the periodic table(hydrogen). Thus, we have the atomic masses of each element. We can convert a mass of a substance to moles to compare to other moles.

#### Explanation:

A mole is a general term we use to compare substances, similar to comparing dozens of items. When you hear a dozen somethings, you can think of a special number that represents a dozen (12 somethings=1 dozen somethings).

A mole is equivalent to $6.02$ x ${10}^{23}$ molecules.

A mole is equivalent to the molar mass of an element or molecule with a common unit: ($g$/$\text{mol}$).

A mole is equivalent to $22.4$ $L$ of a gas at STP(standard temperature and pressure or $273$ $K$ and $1$ $a t m$).

These equivalents are used in conversion problems.