Molar Mass Practice

• A convenient unit for scientist to use

• 1 mole is an easy number to represent the very small or very large numbers we are discussing.

• Molar Mass (g) = 1 Mole = 6.02x10²³ atoms

• A standard which can be used to convert between different units

1 mole = Molar mass of the element or Compound

Molar mass: Atomic mass given in grams

1 mole = Avogadro's number

Avogadro's number= 6.02 x 10²³ atoms

Volume Standard: 22.4L

1 mole= 22.4L

Normally only used for liquids

• The unit you are looking for always goes on the top of the conversion factor

• If both numbers are on the top multiply them

• If one number is on the top and one is on the bottom divide.

• Determine the number of atoms of each element

• Multiply the number of atoms by the atomic mass of each element

• Add the molar masses of each element together for the molar mass of the compound

Mole Conversions

#2 Mass and Moles

Mass & Moles

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1 mole = molar mass (g), calculate from PTE.

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To convert from…

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moles to mass, multiply by molar mass

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mass to moles, divide by molar mass

Example: What is the mass of 0.82 moles of lithium
carbonate, Li2CO3?

Moles to Mass

Multiply moles by molar mass.

Example: How many moles are in 2.3 g sodium chloride,
NaCl?

Mass to Moles

Divide mass by molar mass.

• The unit you are looking for always goes on the top of the conversion factor

• If both numbers are on the top multiply them

• If one number is on the top and one is on the bottom divide.