Answers to Lab Problems

  
  1) A 157.82 g sample of MgNO3 . ???H2O in an evaporating dish is heated until it is dry.  The mass of the evaporating dish is 152 g.  The mass of the anhydrous sample and the evaporating dish is 154.58 g MgNO3.  What is the formula for the hydrate and name the hydrate?

MgNO3 . 6H2O

magnesium nitrate hexahydrate

2) A 0.36 g sample of  Mg is reacted with an excess of hydrochloric acid at  24C and
    100.1 KPa.  The resulting hydrogen gas is collected under water.  The objective is to
     generate the ideal gas constant experimentally.  The volume of the gas collected was
    368 mL.  What was the ideal gas constant found in lab?  What was the percent error?

     8.02 KPa dm3            2.3 % error      
               mol K

3) How many mL of 1.00 M NaOH are needed to neutralize a 10.00 mL aliquot of
    1 M HCl after it has been partially neutralized to a .20 M HCl solution by the
     addition of 0.25 g CaCO3 antacid?

       10 mL NaOH required to neutralize HCl

 

 

 
 

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