Moles

The following problems refer to FeSO4.

a. Is the compound ionic or molecular? How do you know?

b.Calculate the oxidation state of the iron.

c. Write the proper name of the compound.

d.Calculate the oxidation state of the sulfur in the SO4

2- ion.

e. Write the reaction that would occur between FeSO4 and NaCl.

f. Calculate how many moles of NaCl are needed to react with 15.4 moles of FeSO4.

Moles

What coefficients mean:

2 Na + Cl2 2NaCl

2 Na 1 Cl2 2NaCl

4 Na

4Cl2

Reaction Stoich.

Moles

2 Na + Cl2 2NaCl

6 moles Na

10 atoms Na

ONLY WORKS FOR

MOLES, MOLECULES, ATOMS

Reaction Stoichiometry

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

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 4.41 g of Li to form Li2O? (Ans: 5.08 g)

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

7. 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

Calculate the mass of aluminum required to produce 750.0 g of iron. Also calculate the formula units of Fe2O3 that are used in the process.

Al + Fe2O3 Al2O3 + Fe

363 g Al, 4.05 X 1024

What mass of oxygen is needed to react with 16.7 g of iron to form Iron(III)oxide? How many molecules of O2 are used?

4Fe + 3O2 2Fe2O3

Ans: 7.18 g, 1.35 X 1023 atoms

Lead(II)Nitrate reacts with potassium iodide to form potassium nitrate and lead(II)iodide.

a. Write the balanced reaction

b. What type of reaction is this?

c. Calculate the grams of potassium nitrate formed from the reaction of 18.0 g of lead(II)nitrate.

d. Calculate atoms of iodine in the lead(II) iodide

Moles

1. Sandwich analogy:

14 slices of bread

4 pieces of turkey (low fat)

Maximum # of sandwiches?

2. Limiting Reactant – Totally consumed in a reaction. No leftovers

Limiting Reactant

1. 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)

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

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

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)

5. 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)

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)

7. 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

Moles

A. Formula:

Actual Yield X 100 = % Yield

Theoretical Yield

Percent Yield

1. 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%)

2. 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%)

3. An aluminum ladder oxidizes according the following unbalanced equation:

Al + O2 Al2O3

a. 100.0 grams of aluminum reacted with excess oxygen. Calculate the theoretical yield. (189 g)

b. If the percent yield was 67.4%, calculate the actual yield. (127 g)

c. Calculate how many grams of oxygen were used. (88.9 g)

d. Identify the type of reaction that occurred.

11.5 grams of sodium reacts with 15.0 grams of chlorine (Cl2) to form sodium chloride. 18.2 grams of NaCl are collected.

a.Write the balanced chemical equation.b.Identify the limiting reactant.c.Calculate the theoretical yield of NaCl.

(24.7g)d.Calculate the percent yield. (73.7%)e.If the percent yield for a different trial

(starting with same amounts) was only 60.4%, calculate the actual yield.

f. Identify the type of reaction that occurred.

Moles

1. Molarity = measure of the concentration of a solution

2. Molarity = moles/literSimilar to Density = g/L

Molarity

Moles

3. Which is more concentrated?

1 M HCl 3 M HCl

Molarity

Moles

1. What is the molarity of a soln that contains 49.05 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)

Molarity

Moles

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)

Molarity

Moles

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)

Molarity

Moles

1. Mixing from a solid2. How would you prepare 350.0 mL of

0.500 M Na2SO4?

Mixing From a Solid

Moles

Moles

3. Write directions for the preparation of 500.0 mL of 0.133 M KMnO4 (10.5g)

4. Write directions for the preparation of 250.0 mL of 0.00200 M NaOH (0.02 g)

Mixing From a Solid

Moles

1. Dilution Formula:

M1V1 = M2V2

2. Used when you are starting with a more concentrated soln. (Grape juice concentrate, Coke syrup)

Diluting from a Solution

Moles

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)

Diluting from a Solution

MolesThe following questions refer to a 0.0987 M solution of NaNO3.

a. Calculate how many grams of NaNO3 are present in 50.0 mL of the solution. (0.419 g)

b. Calculate the volume of the solution required to provide 0.188 grams of NaNO3. (22.4 mL)

c. State how you would prepare 500.0 mL of the solution starting with solid NaNO3. (4.19 g)

d. State how you would prepare 500.0 mL of the solution starting with a large 3-L bottle of 2.00 M NaNO3(aq) (24.7 mL)

c. 1) Mass 4.19 g of NaNO3

2) Place in a small volume of water to dissolve

3) Dilute to 500 mL

d. 1) Measure 24.7 mL of 0.0987 M NaNO3

2) Dilute to 500 mL

MolesThe following questions refer to this equation:

H2SO4 + NaOH H2O + Na2SO4

a. Calculate how many moles of NaOH are present in 25.0 mL of 0.100 M NaOH.

b. Calculate how many grams of Na2SO4 are produced if the 25.0 mL of 0.100 M NaOH reacts.

c. Calculate the moles of H2SO4 that would be required.

d. Calculate the volume of H2SO4 required if the concentration is 0.0800 M.

e. State what type of reaction occurred.

The following questions refer to the following unbalanced reaction of ethanol (C2H5OH )

C2H5OH + O2 CO2 + H2O

a. State what type of reaction is occurring.

b.Calculate the grams of oxygen needed to react with 100.0 grams of ethanol.

c. Calculate the number of CO2 molecules produced.

d.The density of ethanol 0.789 g/cm3. Calculate the volume of ethanol needed to provide 100.0 grams.

Moles5. a) 10.0 mol b) 1.67 mol

7. a) 21.9 g b) 29.3 g c) 6.60 g

11 a) 83.6 g b) 5.74 mol c) 279 g

d) 0.430 g e) 175 g

13. 363 g Fe, 4.05 X 1024 Fe2O3

15. 16.5 g Cu

18. 323 g Cl2

23.a) 1.60 mol b) 1.50 mol c) 2.81 mol

d) 1.90 mol

27.39.4 g

30. 8.80 g CO2, 10.4 g HCl

Moles33. 47.0%

34. 13.8 g

38. 16.4 g

12-26. 22.5 g

12-27. 2.67 L

12-35. 1.27 M

12-37. 0.710 L

12-40. 2541 mL

MolesSodium bicarbonate (NaHCO3) was decomposed to compare the actual mass of sodium carbonate (Na2CO3) to the theoretical mass. About two grams of NaHCO3 was placed in a petri dish. The dish was heated on a hotplate, allowed to cool, and then massed. The theoretical mass of Na2CO3 was calculated from the chemical equation and compared to the actual mass. This experiment was accurate, with a percent error of 5.3%. The experiment was not precise because it produced a range of 0.80 grams in the actual mass of Na2CO3.

1 2 3 4 5 6 7 8 9 10

C D C D B B C C A D

11 12 13 14 15

B D B D D

4. Na2S(s) 2Na+(aq) + S2-(aq)

Lab Notes

• Goggles

• Use aluminum pans instead of petri dishes

• 4 trials total – Mark your dishes

• Wash dishes out at end and leave all materials at station

• BE CLEANER ABOUT THE BALANCE!!!!!

• Ignore back of sheet, use AP lab report format

• All work must be unique