Chemistry 11

Happy New Year Review and Moles and More!

1.     Calculate the number of formula units in 250. g CaCl₂. 1.35 x 10²⁴ f.u.

2.     Calculate the mass of 2.35 x 10²⁰ molecules of CO₂. 0.0172 g

3.     Calculate the STP volume of 10.0 g of CO₂ gas. 5.09 L

4.     Calculate the number of grams CaCl₂ in 350.0 mL of a 0.250 M solution. 9.72 g

5.     Calculate the volume of 0.250 M NaCl solution that would contain 0.17 g NaCl. 0.012 L

6.     1.26 g of AlCl₃ is dissolved in 160. mL of water. Calculate the molarity of the solution. 0.0590 M

7.     12.5 mL of CO₂ gas at STP are dissolved in 250.0 mL of water. Calculate the molarity of the solution. 0.00223 M

8.     16.0 g of Ca react with water. Calculate the volume of H₂ gas produced at STP.

Ca   +   2 H₂O   ----->   H₂   +   Ca(OH)₂       8.9 L

9.     60.0 g of Al react with 60.0 g of O₂. Calculate the amount of excess reactant.   

4Al   +   3O₂   ----->   2Al₂O₃                         6.67 g O₂

10.  What volume of 0.300 M solution must be diluted to a final volume of 1200 mL and have a molarity of 0.2500 M. 1.00L

11.  Calculate the number of grams NaCl produced by the complete reaction of 520 g Cl₂.

2Na    +    Cl₂    ------->    2NaCl                    857 g

12.  If the actual yield of NaCl in the last question was 200.0 g, calculate the percentage yield of NaCl (3 sig figs). 23.3%

13.  200.0 mL 0.200 M HCl reacts with 400. mL  0.150 M NaOH. Calculate the molarity of excess base. 0.0333 M

HCl   +     NaOH       ----->      NaCl    +     H₂O

14.  100.0 mL of 0.250 M HCl solution is diluted by adding 250.0 mL of water, calculate the new concentration. 0.0714 M

15.  65.5 mL of 0.300 M is diluted to a new molarity of 0.0600 M, how much water was added? 262 mL

16.  56.0 mL of 0.100 M HCl reacts with 0.250 M Ba(OH)₂, calculate the volume of base required to completely neutralize the acid. 0.0112 L

17.  Calculate the mass of AlCl₃ required to prepare 250.0 mL of 0.250 M solution. 8.33 g

18.  Calculate the volume of 0.30 M AlCl₃ solution that contains 6.00 g of AlCl₃. 0.15 L

19.  What volume of water would be required to make a

a) 1.54 M solution of NaCl given 75.0 g of solute? 0.833 L

b) 0.0486 M solution of AgNO₃ given 658.0 mg of solute? (Watch units!) 0.0790 L

20.  A 450.0 mL solution is diluted to 1.640 L. At this dilution, it has a concentration of 1.30 M. What was the original concentration? 4.74 M

21.  Calculate the resulting concentration when 250.0 mL of 3.50 M sodium phosphate solution has 850.0 cm³ of water added to it. 0.795 M

22.  What volume of water is needed to dilute 350.0 mL of 4.85 M MgCl₂ solution to a concentration of 0.550 M? (3.09 L – 0.350 L) = 2.74 L

23.  Complete the Balanced equation and state the type of reaction.

__SR__a)  __ 1 Cl_{2 (g)}    +  __ 1 MgBr_{2 (aq)}  ------->  Br_{2 (l)}    +    MgCl_{2 (aq)}

__SR__b)  __ 1 H₂S _(g)   +  __1 Ag _(s)  ------->     Ag₂S _(l) +    H_{2 (g)}

__Dec _c)  __ 2 NaCl _(s)    ------->   2 Na _(l) +   Cl_{2 (g)}

__Comb__d)  __ 1 CH_{4 (g)}    + __2 O_{2 (g)}   ----->  CO_{2 (g)} + 2 H₂O _(g)

__DR__e)  __ 3 H₂SO_{4  (aq)} + ___ 1 Ca₃(PO₄)_{2 (s)}  ------> 2 H₃PO_{4 (aq)} +  3 CaSO_{4 (aq)}

__SR__f)  __ 2 K _(s)    +  __ 2 HOH _(l)  ------>  2 KOH _(aq)  +  H_{2 (g)}

__Syn__g)  __ 3 S_{8 (s)}    +  __ 16 Al _(s)    ------->  8 Al₂S_{3 (s)}

__DR__h)  __ 1 Pb(NO₃)_{2 (aq)}  + __ 2 NaCl _(aq)  ------> 2 NaNO_{3 (aq)}  + PbCl_{2 (s)}

__Syn__i)   __ 3 Sr _(s)    + __ 1 N_{2 (g)}    ------>   Sr₃N_{2 (s)}

__Neut__j)   __ 3 HCl _(aq)  +   __ 1 Al(OH)_{3 (aq)}  -------> AlCl_{3 (aq)}  +  3 H₂O _(l)

24.  Write the reaction (balanced equation) for each reaction given the description. Include phase subscripts!!

            a)  zinc is added to hydrochloric acid

Zn _(s)  +  2 HCl _(aq)     ----->        ZnCl_{2 (aq)}  +  H_{2 (g)}

            b)  A solution of nickel (II) nitrate is added to sodium carbonate.

Ni(NO₃)_{2 (aq)}     + Na₂CO_{3 (aq)} ----->  NiCO_{3 (s)}  +  2 NaNO_{3 (aq)}

            c)  Hexane C₆H_{14 (l)} is burned in air.

__2_C₆H_{14 (g)} + __19_O_{2 (g)} ----->   12 CO_{2 (g)} +   14 H₂O _(g)

            d)  Magnesium hydroxide is added in pieces to a solution of phosphoric acid.

3 Mg(OH)_{2 (aq)}  +  2 H₃PO_{4 (aq)} ----->   Mg₃(PO₄)_{2 (aq)}  +  6 H₂O _(l)

            e)  Iodine crystals are added to a solution of iron (III) chloride.

I_{2 (s)}  +  FeCl_{3 (aq)} ----->    N.R.   

25. For each reaction description, write the balanced chemical equation, total ionic equation and the net ionic equation. Circle spectator ions. All chemical species must have phase subscripts!

      a) a solution of nickel (III) nitrate is reacted with zinc metal.

Non-ionic:         3 Zn _(s)    +  2 Ni(NO₃)_{3  (aq)}  ----->  2 Ni _(s)  +  3 Zn(NO₃)_{2 (aq)}

Total ionic:        3 Zn _(s)   + 2 Ni³⁺ _(aq) + 6 NO₃^- _(aq) -----> 2 Ni _(s) + 3 Zn²⁺ _(aq)  + 6 NO₃^- _(aq)

Net ionic:           3 Zn _(s)    +  2 Ni³⁺ _(aq)  -----> 2 Ni _(s)  +  3 Zn²⁺ _(aq)

      b) a solution of hydrobromic acid is added to aluminum hydroxide solution.

Non-ionic:                     3 HBr _(aq)   +   Al(OH)_{3 (aq)}  -----> AlBr_{3 (aq)} +  3 H₂O _(l)

Total ionic:        3 H⁺_(aq) +  3 Br^- _(aq)  +  Al³⁺ _(aq)  +  3 OH^- _(aq)  -----> Al³⁺ _(aq)  +  3 Br^- _(aq)  +  3 H₂O _(l)

Net ionic:                                               H⁺_(aq)  + OH^- _(aq)  -----> H₂O _(l)

      c) Barium nitrate solution is mixed with a solution of sodium phosphate.

Non-ionic:         2 Na₃PO_{4 (aq)}   + 3 Ba(NO₃)_{2 (aq)} -----> Ba₃(PO₄)_{2 (s)}  +  6 NaNO_{3 (aq)}

Total ionic:   6 Na⁺_(aq) + 2 PO₄^3- _(aq) + 3 Ba²⁺ _(aq) +  6 NO₃^- _(aq) -----> Ba₃(PO₄)_{2 (s)}  +  6 Na⁺ _(aq) + 6 NO₃^- _(aq)

Net ionic:                       3 Ba²⁺ _(aq)  +  2 PO₄^3- _(aq) -----> Ba₃(PO₄)_{2 (s)}