the mole. the mole an amount of substance. pull a really really really really big amount. in the...

THE MOLE

The Mole

an amount of substance.Pull Pull

Pull Pull

Intro to Mole Video

Intro to the Mole Candy Activity

Part 1 - Particles

What is a mole?

standard counting unit in chemistry (abbreviated “mol”)Relates # particles, mass, and volume of gases

YOUR NEW BEST FRIEND - THE MOLE CIRCLE!!!

PARTICLE PLACE

Relates the mole to the number of particles

CONVERSION FACTOR:1 MOLE = 6.02 x 1023 Particles

MOLES AND PARTICLES

6.02 X 1023 is also known as Avogadro’s Number Named after Italian chemist Amadeo Avogadro who determined that at the same temp and pressure, all gasses contained the same number of particles

Examples of Particles (Amount):A

tom

sM

ole

cule

s

Ion

s

Li+, Ni2+, S2-, N3-PO43-, OH-, NH4+

Charged Particles

Form

ula

Un

itsNaCl, CaSO4,

Fe(OH)3, AgNO3

Particles of Ionic Compounds

What is a formula unit?

Molecular Compound

CO2Formula Unit

NaCl

Na+Cl-Na+Cl-Na+Cl-Cl-Na+Cl-Na+Cl-Na+Na+Cl-Na+Cl-Na+Cl-

smallest whole # ratioof ions in the cmpd.

Molecules

How many molecules are in 1 mole of molecules?Pu

ll

6.02 x 1023molecules

How many formula units are in 1 mole of formula units?

Pu

ll

How many atoms are in 1 mole of atoms?Pu

ll

How many ions are in 1 mole of ions?Pu

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1 new conversion factor YOU need to know.

1 mole = 6.02 x 1023 particles

Mole Circle!!!! Particle Place

SO....back to Dim Analysis

Every problem must include for given, conversion factors and answer:

Example: 6.02 x 1023 atoms Fe

Number Substance

Unit

Use units - they must cancelAnswer in correct significant figures

Solving Mole Problems

1. Identify and label Given and Unknown.2. Write down given x __________.3. Put units of given on bottom of first conversion factor.4. Use mole circle to figure out where you are starting, where you are going, how many steps and conversion factors to get you there.5. Set up using dimensional analysis - number, unit, substance for each entry. Make sure units cancel along the way.6. Multiply all items in numerator. Divide by numbers in denominator.7. Answer - sig figs, units.

2.05 x 1024 atoms

SO....back to Dim Analysis

How many atoms are in 3.4 mol of barium atoms?

=3.4 mol 6.02 x 1023 atoms

1 mol2.05 x 1024 atoms

And...How many mols of iron are in 5.6 x 1022 iron atoms?

0.93 mol Fe

=5.6 x 1022 atoms 1 mol

6.02 x 1023 atoms0.093 mol

3.97 x 1024 O atoms

How many oxygen atoms are in 2.2 mol of BaCO3?

=2.2 mol BaCO3 6.02 x 1023 f.u. BaCO3

1 mol BaCO3

3-O atoms

1 f.u. BaCO3

How many carbon atoms are in a mixture of 2.0 mol of CO2 and 3.5 mol of C6H12O6?

=

=

2.0 mol CO2

1 mol CO2

6.02 x 1023 CO2molecules

1 CO2 molecule

1 C atom

3.5 mol C6H12O66.02 x 1023 C6H12O6

molecules

1 mol C6H12O6 1 C6H12O6 molecule

6 C atoms

1.2 x 1024 C atoms

1.26 x 1025 C atoms

1.2 x 1024 C atoms

1.26 x 1025 C atoms+1.38 x 1025 C atoms

Intro to the Mole Candy Activity

Part 2 - Mass

MASS AVE.

Do you know how to measure out 1 mole of sugar or salt or water?The mole is a counting unit, so we would have to count out 6.02 x 1023 particles of each substance. (NO THANKS!)There are 2 ways to measure out a number of moles of a substance:Measure it in GRAMS ( a mass)If a GAS, measure it in LITERS ( a volume)

MASS AVE.

Relates the mole to the mass of one mole of substance

CONVERSION FACTOR:1 MOLE = Molar Mass of Substance

Molar Mass/Atomic Mass/Gram Formula Mass/Molecular Weight

TAKE OUT YOUR PERIODIC TABLE :)

Molar MassPu

ll

AKA: Gram Formula Mass (GFM)

Molecular Formula Mass (MFM)

Formula Mass (FM)

Pu

llMolar mass

Pu

ll

The mass of 1 moleof substance.

Carbon 12.011

Mg 24.03

Au 196.97

1 mol of Carbon = 12.011 g

1 mol Mg = 24.03 g

1 Mol Au = 196.97 g

Pull my Finger

Atom Atomic Mass

Hey that's a NEW conversion factor!

1 mol = molar mass of substance

Molar Mass of a compound

Pu

ll

Simply find the molar mass of each atom and add them together.

What is the molar mass of NaCl?

1 mole of NaCl has a mass of 58.5 gPull Pull

Pu

ll

Na = 23 g

+Cl = 35.5 g

58.5 g

Pu

ll

1 mol Ca = 40g x 1 = 40g1mol O = 16g x 2 = 32g1mol H = 1g x 2 = 2g

74g

+

Pu

ll

1 mol K = 39.1 g x 2 = 78.2 g1 mol S = 32 g x 1 = 32 g1 mol O = 16 g x 4 = 64 g

What is the molar mass of K2SO4?

What is the molar mass of Ca(OH)2?

Mole to Mass and Mass to Mole Problems (same process as mole to particles, particles to mole!)

How many grams of Al are in 3.00 moles of Al?

Answer = 80.94 = 80.9 g Al

What is the mass in grams of 2.7 mol of O2?

Answer = 86.4 = 86 g O2

Determine the number of moles in 5.00 g of H2O.

Answer = 0.277469 = 0.277 mol of H2O

Multi-Step Problems - Use the Mole Circle! Everything MUST go through the Mole!!!

Calculate the number of grams of Na present in 3.00 x 1018 atoms of Na:

= 0.0001146 g or 1.146 x 10-4 g of Na

Calculate the number of atoms of Na in 160.00 grams of Na:

= 4.189 x 1024 atoms of Na

Penicillin, the first of a now large number of antibiotics, has the formula C14H20N2SO4. Calculate the mass of 2.0 x 1010 molecules of penicillin.

Molar mass C14H20N2SO4 = 312.4 grams

= 1.0 x 10-11 grams of penicillin

2.0 x 1010 molecules of penicillin

2.0 x 1010 molecules

Molar mass C14H20N2SO4 = 312.4 grams

6.022 x 1023 molecules

1 mol

1 mol

312.4 grams

= 1.04 x 10-11 grams of penicillin

(0.5 mg) (3) = 1.5 mg

1.5 mg

molar mass caffeine = 194.2 grams

1000 mg

1 g

194.2 g

1 mol

1 mol

6.022 x 1023 molecules

= 4.65 x 1018 molecules of caffeine

How many atoms of carbon would be in 53.5 grams of isopentyl acetate (C7H14O2) ?

Mass of the Part

Mass of the Wholex 100 = % comp

Percent Composition

% by mass of elements in a compound.

To solve: Assume 1 mole of compound. Then you can use.....

Pu

llPu

ll

Mass of Element

Pu

llPu

llMolar Mass of Compound

Find the % composition of water.

1- Determine the formula of the compound and list its elements.

Divide the molar mass of each element by the molar mass of the entire cmpd.

2g H18g H2O=0.11g

3-

0.11g x 100 = 11% H0.89g x 100 = 89% O

Find the % composition when 8.20g of Mg combines with 5.40g of O.

8.20g Mg5.40g O

13.60g MgO+

8.20g Mg

13.60g MgO=x 100 60.3% Mg

5.40g O

13.60g MgOx100 =39.7% O

Pull

Empirical Formulas

Examples of Empirical Formulas

H2OH3PO4CH

H2O2C6H12O6

Not necessarily the "actual" formula!

Pull

Molecular Formulas

Cmpd.EmpiricalFormula

MolecularFormula

glucose

CH2O

C2H4O2

glucose

C2H4O2

CH2Oformaldehyde

CH2O CH2O

acetic acid CH2O C2H4O2

glucose CH2O C6H12O6

How to Calculate Empirical FormulasPull

Pull

Step 1.

Find the number of moles of each element.

(If % is given, assume 100g of compound; % = grams)P

ull

Pull

Step 2.

Divide number of moles of each element by smallest number of moles.

(finding ratio of # moles of each)

Pu

llPu

ll

Step 3.

Find the lowest whole number ratio. Write formula with subscripts reflecting ratio.

An alkaline battery contains 63.0 % Mn and 37.0% oxygen by mass. Find the empirical formula of the cmpd.

An unknown cmpd was analyzed and found to contain 26.56% K, 35.41% Cr, 38.03% O. Find the empirical formula for the compound.

Calculating Molecular Formulas

Molar mass of unknown molecular formula will be given to you!!!

Pull

Pull

Pull

Pull

Step 2.

Determine the molar mass of empirical formula

Pull

Pull

Step 3.Determine ratio of molecular mass to empirical formula mass.

ratio = molecular molar mass (given) calc. molar mass of emp. form

Pull

Pull

Calculating Molecular Formulas

1. The empirical formula of a compound is NO2. Its molecular mass is 92 g/mol. What is its molecular formula?

2. A compound is found to be 40.0% carbon, 6.7% hydrogen and 53.5% oxygen. Its molecular mass is 60.0 g/mol. What is its molecular formula?

Calculating Molecular Formulas:

Step 1: Find the empirical formula mass.Step 2: Divide molar mass by emp. formula mass.Step 3: multiply answer from step 2 by the empirical formula (how? multiply subscripts!)

What is the molecular formula if it's molar mass is 60 g/mol and it's emp. formula is CH4N?

1 mol = 6.02 x 1023 particles1 mol = molar mass

If you can convert mass to mols you can then convert mols to particles.If you can convert particles to mols you can convert mols to mass.

mass is expressed in grams

Particles are atoms, ions, molecules and formula units.

Attachments

Mole Circle Link.docx