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The Mole The Mole It's not a spy, a machine for digging tunnels, a burrowing animal, or a spot of skin pigmentation - it's - a unit of measurement containing about 6.02 x 10 23 particles. Chemists created the mole as their own counting unit. The Chemical Mole 1mole of atoms is

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It's not a spy, a machine for digging tunnels, a burrowing animal, or a spot of skin pigmentation - it's

- a unit of measurement containing about

6.02 x 1023

particles.

  • Chemists created the moleas their own counting unit.

The Chemical Mole


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1mole of atoms is animal, or a spot of skin pigmentation - it's

602,214,199,000,000,000,000,000

atoms!


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Avogadro’s Number animal, or a spot of skin pigmentation - it's

6.02 x 1023 particles / mole


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Just How Big is a Mole? animal, or a spot of skin pigmentation - it's

  • Enough soft drink cans to cover the surface of the earth to a depth of over 200 miles.

  • If you had Avogadro's number of unpopped 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.


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Moles of Elements animal, or a spot of skin pigmentation - it's

  • 1 mole element = (atomic mass) in grams of that element

    1 mole C = 12.011 g C

    1 mole B = 10.81 g B

    1 mole Cu = 63.55 g Cu


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Avogadro’s Number as Conversion Factor animal, or a spot of skin pigmentation - it's

6.02 x 1023 particles

1 mole

or

1 mole

6.02 x 1023 particles

Note that a particle could be an atom OR a molecule!


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Equation to find number of particles! animal, or a spot of skin pigmentation - it's

6.02 x 1023 particles

1 mole

number of moles x = number of particles

Example: How many particles of sucrose are in 3.50 moles?

6.02 x 1023 molecules

1 mole

3.50 mol sucrose x = 2.11 x 1024 molecules of sucrose


Equation to find number of moles l.jpg
Equation to find number of moles! animal, or a spot of skin pigmentation - it's

number of particles x = number of moles

1 mole

6.02 x 1023 particles

Example: How many moles are contained in 4.50 x 1024 atoms of zinc?

1 mole Zn

6.02 x 1023 particles

4.50 x 1024 atoms of zinc x = 7.48 mol Zn


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Learning Check animal, or a spot of skin pigmentation - it's

1. Number of atoms in 0.500 mole of Al

a) 500 Al atoms

b) 6.02 x 1023 Al atoms

c) 3.01 x 1023 Alatoms

2.Number of moles of S in 1.8 x 1024 S atoms

a) 1.0 mole S atoms

b) 3.0 mole S atoms

c) 1.1 x 1048 mole S atoms


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Molar Mass animal, or a spot of skin pigmentation - it's

11.2


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Molar Mass animal, or a spot of skin pigmentation - it's

  • The Mass of 1 mole (in grams)

  • Molar mass is equal to the atomic mass (look on the periodic table)

    1 mole of C atoms = 12.01 g

    1 mole of Au atoms = 196.97g

    1 mole of Cu atoms = 63.55 g

  • Always round to the hundredths place.


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Molar Mass of Molecules and Compounds animal, or a spot of skin pigmentation - it's

Mass in grams of 1 mole equal numerically to the sum of the atomic masses

1 mole of CaCl2

Ca = 40.08 Cl = 35.453

x 2

70.906

40.08 + 70.906 =

110.99 g/mol


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Molar Mass of Molecules and Compounds animal, or a spot of skin pigmentation - it's

1 mole of N2O4

N = 14.007 O = 15.999

x 2 x 4

28.014 63.996

28.014 + 63.996 = 92.01 g/mol


Mole to mass conversion l.jpg

Where will you find the number of grams per mole? animal, or a spot of skin pigmentation - it's

Mole to Mass Conversion

Number of moles x number of grams = mass

1 mole

Example: Calculate the mass in grams of 0.0450 moles of chromium.

0.0450 moles Cr x 52.0 g Cr = 2.34 g Cr

1 mol Cr

The Periodic Table

Look at your Periodic Table


Mass to mole conversion l.jpg

Where will you find the number of grams per mole? animal, or a spot of skin pigmentation - it's

Mass to Mole Conversion

Mass x 1 mole = number of moles

number of grams

Example: How many moles of calcium are there in 525 grams of calcium?

525 g Ca x 1 mol Ca = 13.1 mol Ca

40.1 g Ca

The Periodic Table

Look at your Periodic Table


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Mass to Atoms Conversion animal, or a spot of skin pigmentation - it's

Two steps:

  • Use the mass to moles conversion

  • Now calculate the number of atoms using the molesto particlesequation.


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Example: animal, or a spot of skin pigmentation - it's

How many atoms of gold are in a pure gold nugget having a mass of 25.0 g?

Step 1

Mass x 1 mole = number of moles

number of grams

25.0 g Au x 1 mol Au = 0.13 mol Au

197.0 g Au

Round to the hundredths place!!!!!!


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6.02 x 10 animal, or a spot of skin pigmentation - it's23 particles

1 mole

number of moles x = number of particles

Step 2

0.13 mol Au x = 7.83 x 1022 atoms Au

6.02 x 1023 atoms

1 mole

Round to the hundredths place!!!!!!


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Atoms/Molecules and Grams animal, or a spot of skin pigmentation - it's

How many atoms of Cu are present in 35.4 g of Cu?

35.4 g Cu 1 mol Cu 6.02 X 1023 atoms Cu 63.5 g Cu 1 mol Cu

= 3.4 X 1023 atoms Cu


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Learning Check! animal, or a spot of skin pigmentation - it's

How many atoms of K are present in 78.4 g of K?

78.4 g K 1 mol K 6.02 X 1023 atoms K 39.1 g K 1 mol K

= 1.20 X 1024 atoms K


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Empirical and Molecular Formulas animal, or a spot of skin pigmentation - it's

11.4


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Percent Composition animal, or a spot of skin pigmentation - it's

Mass of element x 100 = percent by mass

Mass of compound

Example: Determine the percent composition of NaHCO3.

Determine the mass of each element first!

%mass element = mass of element in 1 mol compound x 100

molar mass of compound

Percent Na = 22.99 g Na x 100 = 27.37% Na

84.01 g NaHCO3

You have to complete this step for each element in the compound!!!!


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Determine the Percent Composition animal, or a spot of skin pigmentation - it's

from the Formula C2H5OH

  • Divide the mass of each element by the molar mass of the compound and multiply by 100%


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Types of Formulas animal, or a spot of skin pigmentation - it's

  • Empirical Formula

    The formula of a compound that expresses the smallest whole number ratio of the atoms present.

  • Molecular Formula

    The formula that states the actual number of each kind of atom found in one molecule of the compound.


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Determine the Empirical Formula of animal, or a spot of skin pigmentation - it's

Acetic Anhydride if its Percent Composition is

47% Carbon, 47% Oxygen and 6.0% Hydrogen

  • Convert the percentages to grams by assuming you have 100 g of the compound

    • Step can be skipped if given masses


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Determine the Empirical Formula of animal, or a spot of skin pigmentation - it's

Acetic Anhydride if its Percent Composition is

47% Carbon, 47% Oxygen and 6.0% Hydrogen

  • Convert the grams to moles


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Determine the Empirical Formula of animal, or a spot of skin pigmentation - it's

Acetic Anhydride if its Percent Composition is

47% Carbon, 47% Oxygen and 6.0% Hydrogen

  • Divide each by the smallest number of moles


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Determine the Empirical Formula of animal, or a spot of skin pigmentation - it's

Acetic Anhydride if its Percent Composition is

47% Carbon, 47% Oxygen and 6.0% Hydrogen

  • If any of the ratios is not a whole number, multiply all the ratios by a factor to make it a whole number

    • If ratio is ?.5 then multiply by 2; if ?.33 or ?.67 then multiply by 3; if ?.25 or ?.75 then multiply by 4

Multiply all the

Ratios by 3

Because C is 1.3


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Determine the Empirical Formula of animal, or a spot of skin pigmentation - it's

Acetic Anhydride if its Percent Composition is

47% Carbon, 47% Oxygen and 6.0% Hydrogen

  • Use the ratios as the subscripts in the empirical formula

C4H6O3


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Molecular Formulas animal, or a spot of skin pigmentation - it's

  • The molecular formula is a multiple of the empirical formula

  • To determine the molecular formula you need to know the empirical formula and the molar mass of the compound


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Determine the Molecular Formula of Benzopyrene animal, or a spot of skin pigmentation - it's

if it has a molar mass of 252 g and an

empirical formula of C5H3

  • Divide the given molar mass of the compound by the molar mass of the empirical formula

    • Round to the nearest whole number


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Determine the Molecular Formula of Benzopyrene animal, or a spot of skin pigmentation - it's

if it has a molar mass of 252 g and an

empirical formula of C5H3

  • Multiply the empirical formula by the calculated factor to give the molecular formula

    • (C5H3)4 = C20H12


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