CHM 1040: Final 3/4

  1. Calculate the mass percent composition of calcium in Ca(NO3)2.

    A) 24.4%
    B) 39.2%
    C) 11.6%
    D) 16.2%
    E) 59.6%
    A) 24.4%
  2. What type of reaction is responsible when a free element is converted to a compound?

    B) Oxidation-reduction
  3. A compound with molar mass of approximately 80 g/mol has the
    following composition (mass percent): C: 75.9%, H: 6.4%, and N: 17.7%.
    What is its molecular formula?

    C) C5H5N
  4. Which two compounds have the same empirical formula?

    E) C2H5OH and C6H18O3
  5. In the reaction: 2Fe(s) + 3Cl2(g) ->2FeCl3(s) (same as question 8), if 43 grams of iron were reacted, how many grams of FeCl3 could be produced?

    C) 125
  6. Which compound has a molar mass closest to 100 g/mol?

    B) C7H10
  7. Which is a valid, general definition of a salt?

    C) The compound besides water that is formed in an acid-base reaction.
  8. How
    many moles of water may be formed when 12 moles of hydrogen gas are
    mixed with 11 moles of oxygen gas and are allowed to react? 2H2 + O2 --> 2H2O

    C) 12
  9. Which of the following reactions could be classified as a double-displacement reaction?

    B) Pb(NO3)2 (aq) + H2S (aq) --? 2HNO3 (aq) + PbS (s) (OK)
  10. In one word, why do we use average atomic masses for the elements?

    D) isotopes
  11. In the reaction: 2Fe(s) + 3Cl2(g) ->2 FeCl3(s), if 43 grams of iron were reacted, how many moles of iron were reacted?

    D) 0.77
  12. .

    magnesium were to react with the non-metal fluorine, how many electrons
    would each Mg atom lose, and how many would each F atom gain?

    C) Mg: 2; F: 1
  13. What is the net charge of a precipitate formed by two aqueous solutions?

    B) Neutral, because an insoluble salt compound is formed.
  14. Consider the generic reaction A + B —? C. This is an example of a

    C) synthesis.
  15. Calculate the molar mass of lead(II) nitrate (in g/mol).

    C) 331.2
Card Set
CHM 1040: Final 3/4
CHM 1040: Final 3/4