What coefficients mean:

1
Reaction Stoich.

• What coefficients mean
• 2 Na Cl2 ? 2NaCl
• 2 Na 1 Cl2 2NaCl
• 4 Na
• 6 Na

2
Reaction Stoich.

• 2 Na Cl2 ? 2NaCl
• 4 Cl2
• 2 moles Na
• 10 moles Na
• ONLY WORKS FOR MOLES

3
Reaction Stoich.

• 1. How many moles of H2 and O2 must react to form
  6 moles of H2O?
• 2. How many moles of water must react with 0.25
  moles of CaC2?
• CaC2 2H2O ? C2H2 Ca(OH)2

4
Reaction Stoich.

• 3. How many moles of KCl and O2 are formed from
  the decomposition of 6 moles of KClO3?
• 4. How many grams of oxygen are needed to react
  with 14.6 g of Na to form Na2O? (Ans 5.08 g)

5
Reaction Stoich.

• 5. How many grams of oxygen are needed to react
  with 17.5 g of Al? (Ans 15.6)
• Al O2 ? Al2O3
• 6. How many grams of oxygen will react with 25.0
  g of C2H6? (Ans 93.3 g)
• C2H6 O2 ? CO2 H2O

6
Reaction Stoich.

• 7. Lead(II)Nitrate reacts with Potassium iodide
  to form Potassium nitrate and Lead(II)Iodide.
  How many grams of Potassium nitrate are formed
  from the reaction of 18.0 g of Lead(II)Nitrate?
  (Ans 11.0 g)

7
Reaction Stoich.

• 8. How many grams of P4 and O2 are needed to make
  3.62 g of P2O5? (Ans 1.58 g, 2.04 g)
• P4 O2 ? P2O5

8
Reaction Stoich.

• 9. How many grams O2 are needed to react with 209
  g of CH3OH? (Ans 314 g)
• CH3OH O2 ? CO2 H2O

9
Reaction Stoich.

• 10. What mass of oxygen is needed to react with
  16.7 g of iron to form Iron(III)oxide? (Ans
  7.18 g)
• 4Fe 3O2 ? 2Fe2O3

10
Limiting Reactant

• Sandwich analogy
• 13 slices of bread
• 4 pieces of turkey (low fat)
• Maximum of sandwiches?
• 2. Limiting Reactant Totally consumed in a
  reaction. No leftovers

11
Limiting Reactant

• How many grams of H2SO4 can be formed from the
  rxn of 5.00 moles of SO3 and 2.00 moles of H2O?
• SO3 H2O ? H2SO4
• (Ans 196 g)

12
Limiting Reactant

• 2. How many grams of H2O can be formed from the
  rxn of 6.00 moles of H2 and 4.00 moles of O2?
• O2 H2 ? H2O

13
Limiting Reactant

• 3. How many grams of NaCl can be formed from the
  reaction of 0.300 mol of Na and 0.100 mol of Cl2?
  (Ans 11.7 g)
• 2Na Cl2 ? 2NaCl

14
Limiting Reactant

• 4. How many grams of Ag can be formed from the
  rxn of 2.00 g of Zn and 2.50 g of silver nitrate?
  How much excess reactant remains?
• Zn AgNO3 ? Ag Zn(NO3)2
• (Ans 1.59 g Ag, 1.52 g xs zinc)

15
Limiting Reactant

• 7. How many grams of Ag2S can be formed from the
  rxn of 15.6 g of Ag and 2.97 g of H2S? (Assume
  O2 is in excess)
• 4Ag 2H2S O2 ? 2Ag2S 2H2O
• (Ans 18.0 g)

16
Limiting Reactant

• 6. How many grams of CO2 can be formed from the
  rxn of 40.0 g of CH3OH and 46.0 g of O2?
• 2CH3OH 3O2 ? 2CO2 4H2O
• (Ans 42.2 g)

17
Limiting Reactant

• 5. How many grams of Ba3(PO4)2 can be formed
  from the rxn of 3.50 g of Na3PO4 and 6.40 g of
  Ba(NO3)2? (Ans 4.92 g)
• Na3PO4 Ba(NO3)2 ? Ba3(PO4)2 NaNO3

18
Percent Yield

• Formula
• Actual Yield X 100 Yield
• Theoretical Yield

19
Percent Yield

• What is the yield if you start with 10.00 grams
  of C and obtain 1.49 g of H2 gas?
• C H2O ? CO H2
• (Ans 89.2)

20
Percent Yield

• Carbon was heated strongly in sulfur(S8) to form
  carbon disulfide. What is the percent yield if
  you start with 13.51 g of sulfur and collect 12.5
  g of CS2?
• 4C S8 ? 4CS2
• (Ans 78.0)

21
Molarity

• 1. Molarity measure of the concentration of a
  solution
• 2. Molarity moles/liter
• Similar to Density g/L

22
Molarity

• 3. Which is more concentrated?
• 1 M HCl 3 M HCl
• Crowded classroom example

23
Molarity

• 1. What is the molarity of a soln that contains
  49.0 g of H2SO4 in enough water to make 250.0 mL
  of soln? (Ans 2.00 M)
• 2. What is the molarity of a soln made by
  dissolving 23.4 g of Na2SO4 in enough water to
  make 125 mL of soln? (Ans 1.32 M)

24
Molarity

• 3. What mass of HCl is present in 155 mL of 0.540
  M HCl? (Ans 3.06 g)
• 4. How many grams of NaOH are in 5.00 mL of
  0.0900 M NaOH? (Ans 0.018 g)

25
Molarity

• 5. What volume of 0.0900 M NaOH is needed to
  provide 0.00058 moles? (Ans 6.44 mL)
• 6. What volume of 0.0764 M HCl is needed to
  provide 0.0694 g of HCl?(Ans 25 mL)

26
Mixing From a Solid

• 1. Mixing from a solid
• 2. How would you prepare 350.0 mL of 0.500 M
  Na2SO4? (Ans dilute 24.9 g to 350 mL)

27
Mixing From a Solid

• 3. How would you prepare 500.0 mL of 0.133 M
  KMnO4? (Ans dilute 10.5 g to 500 mL)
• 4. How would you prepare 250.0 mL of 0.00200 M
  NaOH? (Ans dilute 0.02 g to 250 mL)

28
Diluting from a Solution

• 1. Dilution Formula
• M1V1 M2V2
• 2. Used when you are starting with a more
  concentrated soln. (Grape juice concentrate,
  Coke syrup)

29
Diluting from a Solution

• 3. What is the molarity of a soln of KCl that is
  prepared by diluting 855 mL of 0.475 M soln to a
  volume of 1.25 L? (Ans 0.325 M)
• 4. You have a 3.00 L bottle of 11.3 M HCl. What
  volume of it must be diluted to make 1.00 L of
  0.555 M HCl? (Ans 49.1 mL)

30

• a) 21.9 g b) 29.3 g c) 6.6 g
• a) 83.6 g b) 5.74 mol c) 279.3g
• d) 0.430 g e) 175 g
• 16.5 g Cu
• 97. a) 16 mol b) 1.5 mol c) 2.81 mol
• d) 1.9 mol

31

• Page 247-248
• 147. NH3 is LR, 28.4 yield
• 153. 26.7 g FeCl3
• Page 251
• a) Mg Pb(NO3)2 ? Mg(NO3)2 Pb
• b) Pb(NO3)2 (NH4)2S ? PbS 2NH4NO3
• c) 2HBr Sr(OH)2 ? 2H2O SrBr2
• a) 0.0233 mol SbF3 b) 0.826 mol SbCl3
• c) 1100 g CCl4 d) 4.75 X 1025 molecules