Associated Topics || Dr. Math Home || Search Dr. Math

### How Much is a Mole?

```
Date: 11/17/2000 at 10:08:42
From: Lindsey
Subject: How much is a mole of something

I am working on a dimensional analysis problem for chemistry and the
question requires you to know how many grams are in a mole. How many
are there?
```

```
Date: 11/17/2000 at 10:14:50
From: Doctor Mitteldorf
Subject: Re: How much is a mole of something

A mole isn't a specific number of grams - it's a specific number of
molecules. One mole of any material is 6.02*10^23 molecules of that
material.

The reason for this strange, rather large number is that it turns out
to be a convenient way to work with macroscopic proportions.

6.02*10^23 is called Avogadro's number, and it is the number of
protons in a gram. That also makes it a conversion factor between
atomic weight units and grams.

For example, a mole of hydrogen atoms weighs exactly 1 gram, because
atomic hydrogen has atomic weight of 1. A mole of water is 18 grams of
water, because each water molecule consists of 2 hydrogen atoms
(atomic weight 1 each) + 1 oxygen atom (atomic weight 16 each).

- Doctor Mitteldorf, The Math Forum
http://mathforum.org/dr.math/
```
Associated Topics:
High School Physics/Chemistry

Search the Dr. Math Library:

 Find items containing (put spaces between keywords):   Click only once for faster results: [ Choose "whole words" when searching for a word like age.] all keywords, in any order at least one, that exact phrase parts of words whole words

Submit your own question to Dr. Math
Math Forum Home || Math Library || Quick Reference || Math Forum Search