Chapter 9 Worksheet.doc

Chapter 9 Worksheet #1

1. Show that the following equation obeys the law of conservation of mass. (First, convert the equation into terms of interacting particles, then convert to moles, then convert to mass. Use pg. 239 as an

example).

2 KClO3 (s) → 2 KCl (s) + 3O2 (g) Total particles of

reactants: 

Total particles of products:

Total moles of reactants:  Total moles of products:

Total mass of reactants:  Total mass of products:

2. How many grams of calcium sulfide would be needed to react completely with 4.50 g of silver nitrate to form solid silver sulfide and aqueous calcium nitrate?

A. Write the balanced chemical equation, using the correct formulas.

B. Find the number of moles of the given substance.

C. Convert moles of the required substance to grams and solve.

3. Methanol (CH3OH) is used in the production of many chemicals. Methanol is made by reacting carbon monoxide and hydrogen at high temperature and pressure.

CO (g) + 2H2 (g) → CH3OH (g)

A. How many grams of hydrogen would be required to completely react with 8.72 mol CO?

B. How many grams of each reactant are needed to produce 360. g CH3OH?

4. Carbon disulfide is an important industrial solvent. It is prepared by the reaction of carbon with sulfur dioxide.

____ C (s) + ____ SO2 (g) → ____ CS2 (l) + ____ CO (g)

A. Calculate the number of moles of CO produced from 2.46 moles of SO2 that completely react with C.

B. Calculate the number of grams of CS2 that form when 8.7 moles of C are reacted with SO2.

C. How many moles of CS2 form when 2.7 mol C reacts?

D. How many moles of carbon are needed to react with 5.44 mol SO2?

E. How many moles of carbon monoxide form at the same time that 0.246 mol CS2 forms?

F. How many mol SO2 are required to make 118 mol CS2?

_________mol CS2

_________mol C

_________mol CO

_________mol SO2 _________mol CO

Chapter 9 Worksheet #2

1. What mass of solid lead (II) chloride, PbCl2, can be produced by the reaction of 56.9 g of aqueous NaCl in aqueous Pb(NO3)2?

A. Write the balanced chemical equation, using the correct formulas.

B. Find the number of moles of the given substance.

C. Convert moles of the required substance to grams and solve.

2. What is the limiting reactant if 3.6 mol of aluminum and 5.3 mol of chlorine gas react to form aluminum chloride. How many moles of aluminum chloride are formed?

Write the equation: __________________________________________ Known/Unknown: __________________________________________

3. What is the limiting reactant if 6.4 mol of hydrogen gas react with 3.4 mol oxygen gas to form water. What mass of water is formed?

Write the equation: __________________________________________ Known/Unknown: __________________________________________

_______________ Limiting reagent

_______ mol AlCl3

_______________ Limiting reagent

4. The reaction of fluorine with ammonia produces dinitrogen tetrafluroride and hydrogen fluoride. Write the products below and balance the equation.

____ F2 (g) + ____ NH3 (g) →

A. If you have 68.6 g NH3, how many grams of F2 are required for complete reaction?

B. How many grams of NH3 are required to produce 4.65 g HF?

C. How many grams of N2F4 can be produced from 225 g F2?

5. Lithium nitride reacts with water to form ammonia and aqueous lithium hydroxide. Balance the equation and then solve the problems below.

____Li3N (s) + _____H2O (l) → ____NH3 (g) + ____LiOH (aq)

a. What mass of water is needed to react with 32.9 g Li3N?

b. When 32.9 g of Li3N are used, how many molecules of NH3 are produced?

c. Calculate the number of grams of Li3N that must be added to an excess of water to produce 15.0 L NH3?

6. Find the limiting reagent for the given combination of reactants, calculate the moles of product formed, and calculate the number of moles of excess reagent remaining after the reaction.

2 Al + 3 Cl2 → 2 AlCl3

3.6 mol 5.3 mol

Limiting reagent:

_______________________________

Moles of product formed:

_______________________________

Chapter 9 Worksheet #3

Moles Conversions, Limiting Reagents & Percent Yield

1. A reaction started with 384 grams of S6 (s). Assuming an unlimited supply of oxygen, what is the calculated yield and the percent yield if only 680 grams of sulfur dioxide are produced?

Balanced equation: _________________________________________________ Known/Unknown: __________________________________________________

2. If 7.5 grams of NH3 are produced, how many grams of H2 reacted? N2 + 3H2  2NH3

3. For the balanced equation below, find the limiting reagent for the given combination of reactants,

calculate the moles of product formed, and calculate the number of moles of excess reagent remaining after the reaction.

2 H2 + O2 → 2 H2O

6.4 mol 3.4 mol

4. Calcium carbonate reacts with phosphoric acid to produce calcium phosphate, carbon dioxide, and water. 3 CaCO3 (s) + 2 H3PO4 (aq) → Ca3(PO4)2 (aq) + 3 CO2 (g) + 3 H2O (l)

A. How many grams of carbon dioxide are produced if 19.9 g CaCO3 is reacted with 5.66 g H3PO4? Hint: Find the limiting reagent!

Limiting reagent:

_______________________________

Moles of product formed:

_______________________________

Moles of excess reagent remaining: _______________________________ Theoretical yield: __________

Actual yield: _______________

B. If 2.999 g of CO2 are actually produced in the laboratory, what is the percent yield of the reaction? Hint: use the value you solved for in part a.

5. Nitric acid and zinc react to form zinc nitrate, ammonium nitrate, and water.

4 Zn (s) + 10 HNO3 (aq) → 4 Zn(NO3)2 (aq) + NH4NO3 (aq) + 3 H2O (l) A. How many atoms of zinc react with 1.49 g HNO3?

B. Calculate the number of grams of water that are produced if 23.4g of HNO3 react with 29.1 g Zn.

C. If 1.77g of water are actually produced in the reaction, what is the percent yield of the water?

6. Heating an ore of antimony (Sb2S3) in the presences of iron gives the element antimony and iron (II) sulfide.

Sb2S3 (s) + 3 Fe (s) → 2 Sb (s) + 3 FeS (s)

When 15.0 g Sb2S3 reacts with an excess of Fe, 9.84 g Sb is produced. What is the percent yield of this reaction?

7. When 50.0 g of silicon dioxide is heated with an excess of carbon, 32.2 g of silicon carbide is produced. SiO2 (s) + 3 Cl (s) → SiC (s) + 2 CO (g)

a. What is the percent yield of this reaction?

b. How many grams of CO gas are made?

8. Ammonium nitrate will decompose explosively at high temperatures to form nitrogen, oxygen, and water vapor.

2 NH4NO3 (s) → 2 N2 (g) + 4 H2O (g) + O2 (g)

Chapter 9 – Stoichiometry Review

Know the following terms:

stoichiometry percent yield actual yield

theoretical yield gram formula mass

Law of Conservation of Mass

excess reagent limiting reagent mol-mol ratio

Problems:

1. According to the reaction below, what is the mole ratio of aluminum sulfate to aluminum chloride? ____ Al2(SO4)3 + ____ BaCl2  ____ BaSO4 + ____ AlCl3

a) 2:1 b) 1:2 c) 2:2 d) 3:2

2. From the same equation, what is the mole ratio between barium sulfate and aluminum chloride?

a) 2:1 b) 1:2 c) 2:2 d) 3:2

3. What conversion factor from the reaction below would you use to begin converting 4.56g of N2 to moles of NH3 produced? N2 + 3 H2  2 NH3

4. How many moles of NH3 may be produced from 1.20 moles of N2 assuming that hydrogen is excess. N2 + 3 H2  2 NH3

5. Calculate the number of moles of H2 produced from 0.78 moles Ga and 1.92 moles HCl? ____ Ga + ____ HCl  ____ GaCl3 + ____ H2

6. How many moles of H2O2 are required to react with 11.0 g of N2H4 according to the following reaction? 7 H2O2 + N2H4  2 HNO3 + 8 H2O

7. How many grams of S are formed at STP from the reaction of 6.80 g of H2S and 7.43L O2 according to the following reaction? 2 H2S + SO2  3 S + 2 H2O

8. Thin films of silicon, used in fabrication of electronic components, may be prepared by the decomposition of silane. What mass (in g) of SiH4 is required to prepare 0.2173 g of silicon?

9. The reaction of 0.68 g of NH3 with excess O2 according to the following reaction yields 0.98 g of NO. What is the percent yield? 4 NH3 + 5 O2  4 NO + 6 H2O

10. A chemist combines 6.32g of C2H2 and 12.2g of oxygen. How many grams of carbon dioxide are produced? What is the limiting reactant? How many grams excess reagent remain after the previous reaction?

2C2H2(g) + 5O2(g)  4CO2(g) + 2 H2O(l)

11. Hydrazine (N2H4) is used as rocket fuel. It reacts with oxygen to form nitrogen and water. N2H4 (l) + O2 (g) → N2 (g) + 2 H2O (g)

a. How many liters of N2 (at STP) form when 1.0 kg N2H4 reacts with 1.0 kg H2O?

b. How many grams of excess reagent remain after the reaction?

Limiting reagent:

_______________________________

Grams of product formed:

_______________________________