Moles, Empirical Formulas & Percentage Composition - Disk #5


  1. __________ Heating 1.16 grams of KClO3 yields .7 grams of KCl. The loss in weight is .45 grams. What is the weight of oxygen in 1.16 grams of KClO3?
  2. __________ Find the weight of Carbon (C) in a mole of CO2.
  3. __________ What is the percentage of Carbon (C) in a mole of CO2?
  4. __________ How many grams of Hydrogen (H) are there in one mole of H2O?
  5. __________ What is the percentage of Hydrogen (H) in one mole of H2O?
  6. __________ What is the gram-molecular weight of H2O?
  7. __________ How many grams of Oxygen (O) are there in one mole of H2O?
  8. __________ What is the percentage of Oxygen (O) in one mole of H2O?
  9. __________ How many grams of Oxygen (O) are there in 100 grams of water?
  10. __________ How many grams of Cu are contained in 3 grams of a compound which is 44% Copper (Cu)?
  11. __________ How many grams of a compound would be needed to supply 67 grams of Nickel (Ni) if the compound contains 45.3% Nickel?
  12. __________ What is the weight percent of Zinc (Zn) in ZnCl2? Atomic wts: Zn=65.4 Cl=35.5
  13. __________ What is the weight percent Sodium (Na) in NaClO4? Atomic wts: Na= 23 Cl=35.5 O=16
  14. __________ Glucose has the formula C6H12O6. How many moles of carbon are in 1 mole of glucose?
  15. __________ The molecular formula for glucose is C6H12O6. What is its empirical formula?
  16. __________ The molecular formula for benzene is C6H6. What is the empirical formula?
  17. __________ The molecular formula for cyclohexane is C6H12. What is the empirical formula?
  18. __________ The molecular formula for hydrogen peroxide is H2O2. What is its empirical formula?
  19. __________ Calculate the empirical formula for a compound which is 70% Iron (Fe) and 30% Oxygen (O).
  20. __________ How many grams of Fe are there in 100 grams of a compound which is 70% Iron?
  21. __________ How many moles of Fe are there in 70 grams of Iron? (Atomic Weight of Fe is 55.8)
  22. __________ How many moles of Oxygen are there in 30 grams of Oxygen? (Atomic Weight of O is 16)
  23. __________ Calculate the molecular formula of a compound which has the empirical formula CH2 and a molecular formula of 42.
  24. __________ What is the formula weight of CH2? Atomic wts: C=12 H=1
  25. __________ How many CH2 units are can there be in a molecule with a molecular weight of 42?
  26. __________ What is the empirical formula of a compound that contains 44.3% Copper (Cu) and 55.7% Bromine (Br)? Atomic wts: Cu=63.5 Br=79.9
  27. __________ How many grams of Cu are there in 100 grams of the above compound?
  28. __________ How many grams of Br are there in 100 grams of the above compound?
  29. __________ How many moles of Cu are in 44.3 grams? Atomic wts: Cu=63.5 Br=79.9
  30. __________ How many moles of Br are in 55.6 grams?
  31. __________ What is the empirical formula of a compound which contains 49.4% Potassium (K), 20.3% Sulfur (S), and 30.3% Oxygen (O)? Atomic wts: K=39.1 S=32.1 O=16
  32. __________ What is the empirical formula of a compound which contains 50.1% Sulfur (S) and 49.9% Oxygen (O)? Atomic wts: S-32.1 O-16
  33. __________ What is the empirical formula of a compound which contains 42.8% Carbon (C) and 57.2% Oxygen (O)? Atomic wts: C=12 O=16
  34. __________ What is the empirical formula of a compound which contains 37.5% Carbon (C), 12.5% Hydrogen (H), and 50% Oxygen (O)? Atomic wts: C=12 H=1 O=16
  35. __________ What is the empirical formula of a compound which contains 46.7% Nitrogen (N) and 53.3% Oxygen (O)? Atomic wts: N=14 O=16

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