the mole. the mole an amount of substance. pull a really really really really big amount. in the...
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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
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AKA: Gram Formula Mass (GFM)
Molecular Formula Mass (MFM)
Formula Mass (FM)
Pu
llMolar mass
Pu
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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
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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
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Na = 23 g
+Cl = 35.5 g
58.5 g
Pu
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1 mol Ca = 40g x 1 = 40g1mol O = 16g x 2 = 32g1mol H = 1g x 2 = 2g
74g
+
Pu
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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