Molar Mass and Moles
Table of Contents
1. Molar Mass and Moles
1.1. Definitions
1.1.1. Definition of Avogardo's Number
The size of a mole, or \(6.022149e+23\) or \((6.02\times10^{23})\)
1.1.2. Definition of Mole
A standard unit in chemistry for measuring large amounts of very small entities like atoms, molecules, and etc. NOTE: Mole is equivelant to the atomic mass of the molecule/compound.
\[ 1 Mole = (6.022\times10^{23})\]
1.1.3. Standard value of Molar Mass
\(\frac{g}{mol}\) or gram per mole
1.2. Formula
To setup the equation, make 4 boxes, of which only the bottom-left box will be unused.
- The top-left box is the given atoms.
- The top-right box is usually assumed to be 1 as long as known.
- The bottom-right box is Avogardo's Number or the size of the mole.
| Given | Need | |-------+--------------| | | Given (Unit) | | | |
Example setup:
| 9.25*10^{58} | 1 |
|--------------+--------------|
| | 6.02*10^{23} |
Then after setting the equaton up, solve as per the following formula:
\begin{equation} \frac{(GIVEN)\times(NEED)}{(GIVEN_{UNIT})} \end{equation}- Finding grams from moles
- The Given (Unit) is the given unit, of which is 1,
- The Need is the molar mass of the element,
- The Given is the given mol of the element
- Finding moles from grams
- The Given (Unit) is the given unit, of which is atomic mass of the element,
- The Need is the molar mass of the element,
- The Given is the given mol of the element
1.2.1. Examples
How many moles are in \(7.8\times10^{23}\) molecules of water?
\begin{equation} \frac{((7.8\times10^{23})\times1)}{(6.02\times10^{23})} \end{equation}- Answer: \(1.29 Moles\)
How many molecules are in 3.0 moles of sugar?
\begin{equation} \frac{(3\times(6.02\times10^{23}))}{1} \end{equation}- Answer: $18×1025