11.2 molar mass moles grams by lanyuehua

VIEWS: 57 PAGES: 9

									• Molar Mass = mass in grams of one mole
  – Units grams/mole
• For elements, molar mass = atomic mass


  H              C               O Mg
  1.0           12.0            16.0           24.3
• Why aren’t all atomic masses whole numbers?
  – Remember that atomic masses are averages of all the
    isotopes
• Molecular mass = protons + neutrons = amu
  (amu = atomic mass units)
• Hydrogen atom has 1 proton = 1 amu




• Oxygen atom has 8 protons and 8 neutrons =
  16 amu
    Calculate the molar mass
• HCl      (think H1Cl1)
  1* 1.0 + 1* 35.5 = 36.5 g/mol
• Al2O3
  2 * 27.0 + 3 * 16.0 = 102 g/mol
• C25H52
  25 * 12.0 + 52 * 1.0 = 352 g/mol
• C6H12O6
  6 * 12.0 + 12 * 1.0 + 6 * 16.0 = 180 g/mol
• Mg(ClO3)2
  1* 24.3 + 2 * 35.5 + 6 * 16.0 = 191.3 g/mol
    Calculate the molar mass

• K3PO4         • (NH4)3PO4
  212.3 g/mol     149 g/mol


• Ca3(PO4)2     • BaSO4
  310.3 g/mol     233.4 g/mol


• H2SO4         • (NH4)3Fe(CN)6
  98.1 g/mol      265.8 g/mol
         Find the Molar Mass
• BeF2             • Al(OH)3
  47 g/mol           78 g/mol


• K 3P             • Ca(NO3)2
  148.3 g/mol        164.1 g/mol


• (NH4)2O          • LiNO3
  52 g/mol           68.9 g/mol
 Now we can use molar mass to
convert between moles and grams
                   ÷

      Mass     Molar Mass
                            Moles
     (grams)




                  x
• How many grams are in 2 moles of carbon?




• How many moles are in 27 grams of water?
• How many grams are in 0.75 moles of aluminum
  hydroxide?




• How many moles are in 475 grams of bromine?
      Complete in your notes showing your work!

• Determine the molar mass   • Calculate the moles
  –   K3PO4                    – 234 g NaCl
  –   Ca3(PO4)2                – 572 g MgCl2
  –   HCl                      – 23 g C6H12O6
  –   H2O
  –   BaSO4                  • Calculate the mass
                               –   3.45 mol K
                               –   1.75 mol CO2
                               –   5.2 mol KNO3
                               –   4.48 mol Ca3(PO4)2

								
To top