moles

• MOLE:


  A measurement for the AMOUNT OF SUBSTANCE of a chemical.

  • Unit: mol
• • ONE MOLE of any substance has the same number of particles as Avogadro's constant.
  • The value for AVOGADRO’S CONSTANT is 6.02 x 1023 per mole.
  • The PARTICLES mentioned can be atoms, molecules, ions & even electrons.

  
• ONE MOLE of any substance has the SAME MASS in grams as its own relative formula mass (Mr).

  
• Moles = mass / RELATIVE FORMULA MASS
• Find the number of moles in 32g of Methane (CH4):

  Mr = 12 + 1 + 1 + 1 + 1 = 16

  • Moles = 32 / 16 = 2mol

  
• Mass = moles x Mr of element
• Find the mass of 3.5mol of Ammonia (NH3):

  Mr = 14 + 1 + 1 + 1 = 17

  • Mass = moles x Mr = 3.5 x 17 = 59.5g

  
• 1/40 x 6.02 x 10^23 = 1.51 x 10^22

  
• moles of C70 molecules = 1/70 = 0.0142857

  • molecules = 0.0142857 x 6.02 x 10^23 = 8.6 x 10^21

  
• 0.15

  
• 23 / 6.02 x 10^23 = 3.82 x 10^-23

  
• 50.4kg = 50400g

  • 50400 / 28 = 1.8 x 10^3