Calculating Mass of a Number of Moles

• Moles and Molar Mass:

  • The mole is a unit that measures the amount of substance. One mole of any substance contains $6.022×10^23$particles (Avogadro's number).
  • Molar mass is the mass of one mole of a substance (measured in grams per mole, g/mol). It's numerically equal to the relative atomic or molecular mass of a substance.
• • Calculating Mass from Moles:
  • Use the formula: Mass (g)=Moles×Molar Mass (g/mol)Mass (g)=Moles×Molar Mass (g/mol)
  • For example, if you have 2 moles of water (H₂O) and the molar mass of H₂O is 18 g/mol, the mass would be: 2 moles×18 g/mol=36 2moles×18 g/mol=36 g
  • Calculating Moles from Mass:
  • Rearrange the formula to find moles if you know the mass: Moles=Mass (g)Molar Mass (g/mol)Moles=Molar Mass (g/mol)Mass (g)​
  • If you have 50 g of CO₂ (molar mass = 44 g/mol), then: Moles=50 g44 g/mol≈1.14 moles= 50/44 Moles=44 g/mol50 g​≈1.14 moles