Mole Formulas

1
Mole Formulas

• Notes

2
Remember!!!!!You may not need every formula for
every problem!
3
Changing Mass To Number of Moles

• If you find the mass of a sample of glucose
  (C6H12O6) to be 90.0 g, how many moles of glucose
  do you have?
• of Moles of Substance Mass of
  Sample
  Molar Mass of Substance

Molar mass of glucose is Carbon 12.0 g x 6
atoms 72.0 gHydrogen 1.01 g x 12 atoms
12.1 gOxygen 16.0 x 6 atoms 96.0
g---------180.1 g
N 90.0 180.1
N 0.500 mol
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Changing of Moles To Mass

• What is the mass of 0.75 moles of CuSO4
• Mass of moles molar mass

N .75 mol 159.62 g/mol N 119.715
grams
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Changing of Moles To of Particles

• How many molecules of carbon dioxide are found in
  2.50 moles of carbon dioxide?
• of Particles of mol (6.022 1023)

N 2.50 mol (6.022 1023)
To multiply using scientific notation, multiply
the two numbers with a decimal, move the decimal
so that onlyone number is before the decimal,
and then add to thesuperscript how ever many
places you moved the decimal.
2.50 6.022 15.055Move decimal one place
to left 1.505 1024 number of molecules
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HINT!When you move the decimal to the left,
superscript goes up.when you move it to the
right, superscript goes down!
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Changing of Particles to of Moles

• How many moles of O2 are represented by 7.45 x
  1024 molecules of O 2?
• of mols total of particles
  6.02 1023

N 7.45 1024 6.02 1023
Get the superscripts matching bymoving the
decimal one place tothe right in the bigger
and subtractone from superscript.
N 74.5 1023 6.02 1023
N 12.375 mol
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Changing of Particles To Mass

• This is an example of what might be called a
  "two-step problem". The first step is to change
  the number of particles to number of moles, then
  change the number of moles into mass.What would
  be the mass of 3.75 x 1021 atoms of iron?

Change of atoms to of molesN 3.75
1021 6.02 1023
N .0375 1023 6.02 1023
N.006 mol
Change of moles to massMass of mols
molar mass of substanceMass .006 55.85
Mass .335 grams
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Changing Mass To of Particles

• This would also be a two-step operation. First
  we would change the mass to number of moles, then
  we would change number of moles to number of
  particles.
• How many water molecules would be found in a 54.0
  gram sample of water?

1. Change mass to of moles of mol mass
of sample molar mass
substance Mol 54.0 grams
18.016 g/mol Mol 2.997
2.Change moles to particlesParticles moles
(6.021023) N 2.997 6.02 1023 N
2.997 6.02 N 18.041 N 1.80 1024
molecules
Move decimalso that onlyone is behind it