Calculating Mass of a Number of Moles

• What should you be able to calculate by the end of the video?

  Mass needed for a given number of moles
• What equation is used to calculate the number of moles from mass?

  Number of moles = mass / relative formula mass
• How do you calculate mass from moles?

  Mass = number of moles * relative formula mass
• What is the formula for sodium chloride?

  NaCl
• What is the relative atomic mass of sodium?

  23
• What is the relative atomic mass of chlorine?

  35.5
• How do you find the relative formula mass of sodium chloride?

  Add the atomic masses of sodium and chlorine
• What is the relative formula mass of sodium chloride?

  58.5
• What is the mass of four moles of sodium chloride?

  234 grams
• What is the formula for potassium oxide?

  K₂O
• What is the relative atomic mass of potassium?

  39
• What is the relative atomic mass of oxygen?

  16
• How do you calculate the relative formula mass of potassium oxide?

  Add the atomic masses of two potassium and one oxygen
• What is the relative formula mass of potassium oxide?

  94
• What is the mass of three moles of potassium oxide?

  282 grams
• What is the formula for cesium nitrate?

  CsNO₃
• What is the relative atomic mass of cesium?

  133
• What is the relative atomic mass of nitrogen?

  14
• How do you calculate the relative formula mass of cesium nitrate?

  Add the atomic masses of cesium, nitrogen, and three oxygens
• What is the relative formula mass of cesium nitrate?

  195
• What is the mass of 0.1 moles of cesium nitrate?

  19.5 grams
• What is the relative atomic mass of copper?

  63.5
• What is the formula for copper sulfate?

  CuSO₄
• What is the relative atomic mass of sulfur?

  32
• What is the relative atomic mass of oxygen?

  16
• How do you calculate the relative formula mass of copper sulfate?

  Add the atomic masses of copper, sulfur, and four oxygens
• What is the relative formula mass of copper sulfate?

  159.5
• What is the mass of five moles of copper sulfate?

  797.5 grams
• What is the general process to calculate mass from moles?

  1. Identify the compound's formula.
  2. Find the relative atomic masses of its elements.
  3. Calculate the relative formula mass.
  4. Use the equation: Mass = number of moles * relative formula mass.
• What are the steps to find the relative formula mass of a compound?

  • Identify the number of each type of atom.
  • Multiply the number of atoms by their respective atomic masses.
  • Sum all the values to get the relative formula mass.