Calculations with Moles

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Calculations with Moles
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formula mass (g/mol)
x by
x by
x by
6.02 x 1023
22.4 L/mol
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3 types calculations

• mole-mass (grams)
• mole-volume (liters)
• mole-number of particles (avogadros )

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Moles to Mass (and back)

• For mass-mole conversions
• FM must be calculated

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Mole/Mass Conversions

• What is the mass of 3 moles of sugar?
• formula for sugar C6H12O6
• Step 1 See what mole-map says!
• Remember, mass is in grams!

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Conversions

• Step 2 Find the formula mass of C6H12O6
• 6(12g/mol) 12(1g/mol) 6(16g/mol)

180g/mole
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Conversions

• Step 3
• 180g/mole C6H12O6 x 3 moles
• (3 moles) (180 g 540 g
• mole)

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Mole-mass conversions

• How many moles C6H12O6 are in
• 270.0 grams C6H12O6?
• Step 1 Look at mole map!
• grams divided by formula mass moles
• Step 2
• Formula mass of C6H12O6 180 g/mol

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Mole-mass conversions

• How many moles C6H12O6 are in
• 270.0 grams C6H12O6?
• Step 3
• 270.0 g 1.5 moles
• 180 g/mol

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Mole Volume conversions
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Mole-Volume Conversions

• For any gas
• 1 mole 22.4 liters at STP
• STP standard temperature (0?C)
• and pressure (1 atm)

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Mole-Volume Conversions

• What is volume occupied by 4 moles
• H2(g) at STP?
• Step 1 Look at mole map!
• volume moles x 22.4 L/mole

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Mole-Volume Conversions

• Step 2 Do calculation!
• 4 moles x 22.4 L 89.6 Liters

mole
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Mole-Volume Conversions

• How many moles of N2 are in 33.6 L?
• Mole map
• take liters and divide by 22.4 L/mole

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Mole-Volume Conversions

• Step 2 Do calculation
• 33.6 Liters__ 1.5 moles
• 22.4 L/mole