## Saturday, November 20, 2010

### Converting THE MOLE

Mole conversions. They may seem hard, but they're just like unit conversions.

Things to remember:
-how to calculate molar mass
-the "magic 1" rule
-SIG. FIGS!

OK. Let's start converting!!

*For these conversions, we'll need to use Avogadro's number: 6.022x10^23*
1. particles-->moles
4.24x10^24 C particle-->moles

4.24x10^24particles               1 mole         = 7.04 moles of C
6.022x10^23 particles

2. moles-->particles
1.34 moles moles CO2-->molecules

1.34moles x 6.022x10^23 molecules = 8.07x10^23 molecules of CO2
1 mole

These conversions do not require Avogadro's number. They instead, require a periodic table. Remember how to calculate molar mass!
3. moles-->grams
6.5 moles of C-->grams                                        *Use molar mass of C=12.0g/mol

6.5 moles x 12.0g/mol = 78 grams of C
1 mole

4. grams-->moles
8.2 grams of MgCl2-->moles                                *Use molar mass of MgCl2=95.3g/mol

8.2 grams x 1 mole = 0.086 moles of MgCl2
95.3 g

YAY!! So now, you should know how to convert from moles<->particles and moles<-> grams.
Just for some extra practice, here are a few questions:

1. How many moles of O2 are in 5.53x10^41 molecules of Ag?

2. How many atoms are in 2 moles of C?

3. How many moles are in 94.0g of Pb?

4. Calculate the mass (g) of 7.42x10^12 atoms of C.

And, lastly, here's a video to summarize the converting stuffs. Don't get distracted by the music!
Teehee.

Written by Jialynn.