Practice Problems 9 Chapter 4 CHE 151
Graham/07
1. What is the molar concentration of the copper ions (Cu2+) in a 0.7542 M
solution of copper (II) chloride?
CuCl2(s) Cu2+(aq) + 2 Cl—(aq)
0.7542 mole CuCl2 x 1 mole Cu2+ = 0.7542 mole Cu2+ = 0.7542 M Cu2+
1 L soln. 1 mole CuCl2 1 L soln.
2. What volume of a 0.7542 M copper (II) chloride solution would be required
to provide 0.971 moles of Cu2+ ions?
0.971 mole Cu2+ x 1 L soln. = 1.29 L soln.
0.7542 mole Cu2+
3. Calculate the molarity of of the Cl- ion in a solution prepared by mixing
100. mL of 0.150 M NaCl and 100. mL of 0.150 M MgCl2. Assume the
volumes are additive.
0.100 L NaCl x 0.150 mole NaCl x 1 mole Cl- + 0.100 MgCl2 x 0.150 mole MgCl2 x 2 mole Cl-
soln. 1 L NaCl soln. 1 mole NaCl soln. 1 L MgCl2 soln. 1 mole MgCl2
= 0.0450 mole Cl-
Total volume
of solution = 0.200 L
0.0450 mole Cl- = 0.225 M Cl-
0.200 L soln
4. Characterize the following compounds as soluble or insoluble in water.
a.) Ca3(PO4)2 _insoluble_______ b.) K2S __soluble_______
c.) Hg(NO3)2 _soluble________ d.) ZnSO4 _soluble______
e.) NH4ClO4 ___soluble______
5. Write the overall and the net ionic equation for the combination of potassium
carbonate and copper(II) bromide solutions.
K2CO3(aq) + CuBr2(aq) 2 KBr(aq) + CuCO3(s)
2K+(aq) + CO32-(aq) + Cu2+(aq) + 2 Br-(aq) 2 K+(aq) + 2 Br-(aq) + CuCO3(s) (overall ionic equation)
Cu2+(aq) + CO32-(aq) CuCO3(s) (net ionic equation)
6. What volume, in liters, of 1.00 M Pb(NO3)2 is needed to react completely with
0.500L of 4.00 M NaCl ?
Pb(NO3)2(aq) + 2NaClaq) 2 NaNO3(aq) + PbCl2(s)
0.500 L NaCl x 4.00 mole NaCl x 1 mole Pb(NO3)2 x 1 L Pb(NO3)2 soln =
soln. 1 L NaCl soln. 2 mole NaCl 1.00 mole Pb(NO3)2
1.00 L Pb(NO3)2 soln.
