Composition of Hydrates

1.  A hydrated sodium salt containing 39.7 % water is analyzed as follows:  Na 16.9 %, C
    17.7 %, H 6.67 %, and O 58.8 %.  What is the empirical formula of this salt?

2.  Nicotine is a compound that contains 74.0 % carbon, 8.7 % hydrogen, and 17.3 %
     nitrogen.  If the molecular mass is 162, what is the molecular formula?

3.  Strontium hydroxide is isolated as a hydrate, which means that a certain number of water
     molecules are included in the solid.  When 6.85 grams of the hydrate are dried in an oven,
     3.13 grams of anhydrous Sr(OH)2 are formed.

4.  A 2.5 gram sample of a hydrate of Ca(NO3)2 was heated, and only 1.7 grams of the
     anhydrous salt remained.  What percentage of water was in the hydrate?

5.  A 5.0 gram sample of Cu(NO3) 2 . n H2O is heated, and 3.9 gram sample of the
     anhydrous salt remains.  What is the value of n?


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