# 1 mole = 6.02 x 10 23 atoms 1 mole = atomic mass

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```Name:_KEY________________________________________________________
A. SCIENTIFIC (EXPONENTIAL) NOTATION
Scientific notation uses powers of ten to express very large or very small numbers.
Numbers expressed in scientific notation have a single digit, followed by a decimal and the remainder of the
digits. The number is then multiplied by a power of ten. The exponent is determined by the number of times
the decimal must move to be in this position. Numbers greater than one have a positive exponent, and
numbers between zero and one have a negative exponent.
Example:
5,450g = 5.450 x 103g
0.00027 = 2.7 x 10-4g
TRY: CONVERT BETWEEN SCIENTIFIC NOTATION AND STANDARD NOTATION:
a. 465mL = ___4.65x102_______________ mL g. 0.000 000 000 440 mg = __4.40x10-10________mg
b. 69,755g = __6.9755x104______________ g
h. 5.50 x 103 L = ____5500____________________L
234,241 J = __2.34241x105____________J
i. 2.75 x 106 J = ____2,750,000_________________J
c.
d. 750,000,000,000g = _7.5x1011__________g
j. 3.5 x 10-2 cal = ________0.035_______________cal
e. 0.0125 cm3 = ____1.25x10-2___________cm3 l.
f.
2.29 x 10-6 g = _____0.00000229______________g
0.000086 kPa = __8.6x10-5______________kPa
On many calculators, the power of ten is written as E or EE, or the exponent is separated from the rest of the
numbers. Try dividing one by 500,000,000 (1 ÷ 500,000,000) on your calculator. What do you see?
____________________________. This can be rewritten as __________________________ or
____________________________.
ENTERING NUMBERS IN SCIENTIFIC NOTATION INTO YOUR CALCULATOR: To enter numbers into your
calculator in scientific notation, use the EE or EXP key on your calculator. Enter the base number, then EE or
EXP, followed by the exponent. DO NOT USE THE 10^ KEY! (on the graphing calculator, the EE is shift ,)
TRY: ENTER THE FOLLOWING QUANTITIES INTO YOUR CALCULATOR:
a. 4.51 x 1021
b. 6.02 x 1023
1
b. 9.86 x 10-13
1 mole = molar
mass
(look it up on
the PT!)
MASS
(g)
MOLE
1 mole =
6.02 x 1023
atoms
PARTICLES
(ATOM)
MOLAR MASS AND MOLE CONVERSIONS
Mole: 1 mole = 6.02 x 1023
Avogadro’s number: 6.02 x 1023 atoms = 1 mole
Atoms, particles, molecules, formula units
11
Molar Mass: Periodic table
the mass of of 1 mole of an element (in grams)
Molar mass of Na is 22.99 g/mol
Na
22.9897
CONVERSION FACTORS:
1 mole = 6.02 x 1023 atoms
1 mole = atomic mass (g)
Try:
1. How many atoms are in 6.5 moles of zinc
6.5 moles Zn
6.02 x 1023 atoms Zn
=
3.91 x 1024 atoms Zn
1 mole Zn
2. How many moles of argon are in a sample containing 2.4 x 1024 atoms of argon?
2.4 x 1024 atoms of argon
1 mole
6.02 x 1023 atoms
=
3.99 mol
1 mole
6.9 g
=
0.36 mol
55.8 g
1 mole
=
267.84 g
3. How many moles are in 2.5g of lithium?
2.5 grams Li
4. Find the mass of 4.8moles of iron.
4.8 moles
2
CONVERSION FACTORS:
1 mole = 6.02 x 1023 atoms
1 mole = atomic mass (g)
Two Step Problems:
1. What is the mass of 2.25 x 1025 atoms of lead?
2.25 x 1025 atoms of lead
1 mole
6.02 x 1023 atoms
207.2g
1 mole
=
7744.19g = 7740g
=
3.06 x 1022 atoms
2. How many atoms are in 10.0g of gold?
10 g gold
6.02 x 1023 atoms
1 mole
1 mole
197.0g
PRACTICE PROBLEMS:
a. Convert to moles:
1. 625g of copper
625g of copper
1 mol
64 g Cu
=
9.77 mol Cu
2. 4.25 x 1026 atoms of barium
4.25 x 1026 atoms of barium
1 mol
=
6.02 x 1023 atoms
706 mol Ba
b. How many atoms are in:
1. 2.35 moles of carbon
2.35 moles
6.02 x 1023 atoms
1 mole
=
1.41 x 1024 atoms
2. 4.0g of potassium
4.0 g
3.
6.02 x 1023 atoms
1 mole
=
6.2 x 1022 atoms
1 mole
55.8g
6.02 x 1023 atoms
1 mole
=
1.0 x 1026 atoms
9500g of iron
9500 g Fe
3
1 mole
39.1g
CONVERSION FACTORS:
1 mole = 6.02 x 1023 atoms
1 mole = atomic mass (g)
c. Determine the mass of:
1. 0.250 moles of aluminum
0.250 moles
27.0g
=
1 mole
6.75 g Al
2. 3.48 x 1022 atoms of tin
3.48 x 1022 atoms
3.
1 mole
6.02 x 1023 atoms
118.7g
1 mole
4.48 x 1021 atoms of magnesium - report your answer in regular and scientific notation
4.48 x 1021 atoms
1 mole
6.02 x 1023 atoms
24.3g
1 mole
d. Try:
How many moles is 2.50kg of lead?
Find the mass, in cg, of 3.25 x 1021 atoms of lithium
4
= 6.86 g Sn
= 0.181 g Mg or 1.8 x 10-1
SCIENTIST NOTES
NAME
JOHN DALTON
J. J. THOMSON
CONTRIBUTION/EXPERIMENT
Atomic Theory:
1. All matter is made of atoms (atoms are
indivisible and indestructible)
2. All atoms in an element are identical to each
other in mass and properties
3. Compounds are formed by a combination of 2
or more different kinds of atoms in different
ratios
4. A chemical reaction is a rearrangement of
atoms
5. In reactions, matter is neither created or
destroyed (law of conservation of matter)
 Discovered electrons
 Used cathode rays to show how electrons were
deflected by magnetic forces


ERNEST
RUTHERFORD
NIELS BOHR
5

Gold Foil experiment – proved nuclear form
Discovered a positively charged nucleus
(99.9% of mass of atom)
Atoms are mostly made up of empty space



Discovered electron motion
Said that electrons orbit around the nucleus
Light emissions (next chapter!)
MODEL
Solid Sphere – “Billiard Ball
Model”
-different atoms were drawn at
different sizes
- Negative electrons set in a
sponge of “+” charge
-“Plum Pudding” Model
- “Nuclear” Model
- Protons in nucleus
with
electrons floating outside
nucleus
-
“Solar System” Model
```