1. MOLES Chapter 10

3. Dimensional Analysis All you need to know: Conversion factors
The process
Given with unit x __________ x ___________
EXAMPLE 1
What is the mass of 90 average-sized apples if a dozen apples has a mass of 2.0 kg?
90 apples x 1 dozen apples x kg apples = 15 kg apples
12 apples dozen apples

4. 0.5 bushel x dozen apples x 2.0 kg = 1.0 kg 1 bushel I dozen EXAMPLE 3
If a bushel is a dozen apples and a dozen apples has a mass of 2.0 kg, what is the mass of 0.5 bushel of apples?
0.5 bushel x dozen apples x 2.0 kg = 1.0 kg
1 bushel I dozen
EXAMPLE 3
Assume 2.0 kg of apples is a dozen and that each apple has 8 seeds. How many apple seeds are in 14 kg of apples?
14 kg x 1 dozen x 12 apples x 8 seeds = 672 seeds
2 kg dozen apple

5. JUST HOW MUCH DO YOU HAVE?
We measure the amount of something by using one of three different methods
by mass (bird seed)
by count (screws)
by volume (paint)
Can you go from one to another?

6. by MASS: Molar Mass
# of grams of an element in one mole of that element.
atomic mass of the element with the units of g/mol
Get it from the periodic table
Molar mass of compounds:
add the molar mass of every atom present in the compound
You will use molar mass as a conversion factor to convert between grams and moles.

8. Elements
Find the molar mass on the periodic table round to 0.01 grams/mol
Compounds
ADD the molar mass of every atom present in the compound

9. If you know the MOLAR MASS …
You can convert between grams and moles!
Volume
of gas at STP
1 Mole
Molar mass (g/mol)
Mass
Representative Particles

10. By COUNT: Avogadro's Number How big is 6. 02x1023
If you had Avogadro's number of un-popped popcorn kernels, and spread them across the United States of America, the country would be covered in popcorn to a depth of over 9 miles.
If we were able to count atoms at the rate of 10 million per second, it would take about 2 billion years to count the atoms in one mole.
A mole of coke cans would cover the surface of the earth to a depth of over 200 miles.

11. If you know Avogadro’s number …
You can convert between particles and moles!
Volume
of gas at STP
1 Mole
Avogadro’s Number
6.02 x 10 23
Molar mass (g/mol)
Mass
Representative Particles
Atoms – elements
Formula Units - ionic
Molecules - covalent

12. If you know Molar Volume…
You can convert between Liters and moles!
Volume
of gas at STP
22.4 L / mol
@STP
1 Mole
Avogadro’s Number
6.02 x 10 23
Molar mass (g/mol)
Mass
Representative Particles
Atoms – elements
Formula Units - ionic
Molecules - covalent

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