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Molarity 1 (Worksheet)

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Work in groups on these problems. You should try to answer the questions without referring to your textbook. If you get stuck, try asking another group for help.

  1. Calculate molarity if 25.0 mL of 1.75 M HCl diluted to 65.0 mL.  

 

  1. Calculate molarity by dissolving 25.0g NaOH in 325 mL of solution.

 

  1. Calculate grams of solute needed to prepare 225 mL of 0.400 M KBr solution.

 

  1. Calculate mL of 0.650M  KNO3 needed to contain 25.0g KNO3.

 

  1. Which are water soluble? Zn(NO3)2  AlCl3  AgBr  FePO4  CuAc2

 

  1. Calculate grams Ca(OH)2 needed to completely neutralize 50.0 mL of 3.00 M HBr.  

 

  1. Calculate molarity of 35.0 mL KOH solution needed to completely neutralize 22.5 mL of                      1.75 M H2SO4.

 

  1. Calculate volume (mL) of 2.50M H2SO4 needed to completely neutralize 10.0g NaOH(s)

 

     Answers     

  1.  M1V1 = M2V2       (1.71 M)(25.0 mL) = M2(65.0 mL)          M2 = 0.658 M

 

  1.  M = mol/L = (25.0/40.0) / (0.325) = 1.92 mol/L

 

  1.  g = (M)(L)(FW) = (0.400)((0.225)(119) = 10.7 g

 

  1.  (25.0g)(1 mol/101 g)(1000mL/0.650 mol) = 381 mL

 

  1.  Zn(NO3)2  AlCl3   CuAc2
  1. 2 mol Ca(OH)2 = mol HBr                                                                                                            2 (g/74) = (3.00)(0.0500)        5.55 g Ca(OH)2
  1. mol KOH = 2 mol H2SO4                                                                                                               ( M)(mL)  = 2( M)(mL)                                                                                                       (M)(35.0mL) = 2(1.75 M)(22.5 mL)     2.25M KOH    
  1. 2 mol H2SO4 = mol NaOH                                                                                                            2 ( M)(L)  = g/FW                                                                                                                        2 (2.50)(L) = 10.0/40.0      L = 0.0500 50.0 mL