What is the mass in grams of 2.00 x 10^23molecules of F2 Answer

9.What is the mass of 3.06 x 10^22 molecules of CO2?

  • A.135g CO2
  • B. 2.24g CO2
  • C. 14.4g CO2
  • D. 866g CO2
  1. What is the mass in grams of 2.00 x 10^23molecules of F2 (Hint: Molecules-moles-mass)
  • A. 126g F2
  • B. 12.6g F2
  • C. 38g F2
  • D. 3.54 g F2

11.How many moles are in 98.3 grams of aluminum hydroxide, Al(OH)3?

  • A. 3.20 moles
  • B. 1.07 moles
  • C. 1.26 moles
  • D. 1.28 moles

Solution

No. 9

1 mole CO2 (molar mass=44) has 6.023×10^23 molecules So mass of 3.06×10^22 molecules = (44 x 3.06×10^22) / 6.023×10^23 = 2.24 g

No. 10 N(F2)/NA=n(mols) N(F2)=2.00×10^23 NA=6.02×10^23 then,plug in the numbers. 2.00×10^23/6.02*10^23=n 0.332 mols=n NOw, find the molar mass of F2 F=2x 19=38g/mol use the formula n= m/M nM=m 0.332mol x 38g/mol = 12.6g F2

No. 11

(molar mass of Al(OH)3 is 27 + (3 x 16) + (3 x 1) = 78 g/ mole) 98.3 grams x 1 mole = 1.26 moles Al(OH)3 OR (98.3g/78g = 1.26 moles)