Chemistry 20 Mole Conversions. What is a Mole? A term of measurement A counting number – Similar...
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Transcript of Chemistry 20 Mole Conversions. What is a Mole? A term of measurement A counting number – Similar...
What is a Mole?
• A term of measurement• A counting number–Similar to saying 1 dozen = 12 things
• Avogadro's Number (NA)
6.02 x 1023 items
A VERY LARGE NUMBER!!!
= 1 mole
• 3.00 moles of little green peas would cover 250 planets the size of Earth 1m deep in green peas
• 1.00 mole of basketballs would fill a bag the size of the Earth
Molar Mass• Molar mass is the mass of one mole in an
element or compound• Atomic mass tells us that the units are
grams per mole g/molExamples:Carbon, C = 12.01 g/molPhosphorus, P = 30.97 g/mol
Molar Mass ExamplesWhat is the Molar Mass of:Salt, NaCl:Na = 22.99g/mol Cl = 35.45g/mol NaCl = 22.99g/mol + 35.45g/mol = 58.44g/mol
Glucose, C6H12O6:C6 = 6(12.01g/mol) H12 = 12(1.01g/mol) O6 = 6(16.00g/mol)
C6H12O6 = 6(12.01g/mol) +12(1.01g/mol) 6(16.00g/mol)
= 180.18 g/mol
Sodium bicarbonate, NaHCO3:
Na= 22.99g/mol H=1.01g/molC=12.01g/molO = 3(16.00g/mol)
NaHCO3= 22.99g/mol + 1.01g/mol + 12.01g/mol + 3(16.00g/mol)
= 84.01g/mol
Mole Conversion ExamplesA grade eleven chemistry student has 3.00 g of boron tribromide (BBr3). How many moles of BBr3 is this?
Molar mass of BBr3 = 10.81 + 3(79.90) = 250.51g/mol
3.00g BBr3 x 1mole = 0.0120 mole BBr3
250.51g
REMEMBER SIG FIGS!
If I have 50.0g of calcium chlorate (CaClO3)2 how many moles do I have?
Molar Mass (CaClO3)2 =
2(40.08) + 2(35.45) + 6(16.00) = 247.06 g/mol
50.0g (CaClO3)2 x 1 mole = 0.202 mole (CaClO3)2
247.06g
Sig Figs
Determine the mass of the following amount:
6.94 mol barium chloride (BaCl2)
Molar Mass BaCl2 = 137.33 + 2(35.45) = 208.23 g/mol
6.94 mol BaCl2 x 208.23 g = 1.45 x 103 g BaCl2
1 mole
Remember only 3 sig figs
Mole Conversions
RespectiveParticles
Moles
Avogadro’s Number
6.02 x 1023 molecules or
atoms or formula units
Mole Conversion ExamplesIf a chemist is experimenting with 5 700 000 000 atoms of lead how many moles is she dealing with?
Avogadro’s number = 6.02 x 1023 atoms
5 700 000 000 atoms Pb x 1 mole = 9.5 x 10-15 mol
6.02 x 1023 atoms
2 sig figs 2 sig figs
How many moles is in 2.97 x 1025 atoms of Vanadium?
2.97 x 1025 atoms of V x 1 mole
6.02 x 1023 atoms= 49.3 moles of V
Determine the number of molecules in the following:a) 1.01 moles of bismuth
1.01 mol Bi x 6.02 x 1023 atoms
1 mole= 6.08 x 1023 atoms of Bi
If the students in a chemistry 20 class have 7.66 x 1019 molecules of hydrogen peroxide, H2O2, how many moles do they have?
7.66 x 1019 molecules x 1 mole
6.02 x 1023 molecules
= 1.27 x 10-4 molecules of H2O2
Mole Conversion ExamplesDetermine the volume, in liters, occupied by 0.030 moles of helium gas at STP.
0.030 moles He(g) x 22.4L = 0.67 L of He(g)
1 mole
REMEMBER UNITS
How many moles of argon atoms are present in 11.2 L of argon gas at STP?
11.2L Ar(g) x 1 mole = 0.5 mole Ar(g)
22.4L
Mole ConversionsRepresentative
ParticlesVolume at STP
MOLE
Mass
x 1 mole 22.4L
X 22.4L1 mole
x molar mass1mole
x 1mole molar mass
x 1 mole 6.02 x 1023 particles
x 6.02 x 1023 particles1 mole
Mixed Mole Conversion1. Write down the question’s the given
and the unknown.2. Convert the given unit to number of
moles.3. Convert the number of moles found to
the unknown unit.4. Make sure the answer has the correct
unit and number of sig figs.
Mole Conversion ExamplesCalculate the mass, in grams (g), of the following:a) 3.00L of O2(g)
3.00L of O2(g) x 1 mole x 32.00 g = 4.29 g O2(g)
22.4L 1moleb) 15 atoms of gold15 atoms Au(s) x 1 mole x 196.97g = 4.9 x 10-21 g Au
6.02 x 1023 atoms 1 mole
Calculate the number of atoms in 2.0L of SO3 gas.
2.0L SO3(g) x 1 mole x 6.02 x 1023 atoms = 5.3 x 1022 atoms SO3
22.4 L 1 mole