SCH 3U Workbook Answer Key - Unit 2 by Michael Papadimitriou

Francis Libermann Catholic High School Science Department

Grade 11 University Chemistry SCH 3U1 â&#x20AC;&#x201C; Course Workbook Unit 2 Answer Keys

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Avogadro Constant – Understanding Concepts 1. Knowledge: In your own words, define the mole. Use three examples.

2. Thinking: Imagine that $6.02×1023 were evenly distributed among six billion people. How much money would each person receive?

3. Thinking: A typical adult human heart beats an average of 60 times per minute. If you were allotted a mole of heartbeats, how long, in years, could you expect to live? You may assume each year has 365 days.

4. Thinking: Calculate the number of atoms in 3.45 mol of iron, Fe.

5. Thinking: A sample of carbon dioxide, CO2, contains 2.56×1024 molecules. a.) How many moles of carbon dioxide are present?

b.) How many moles of atoms are present?

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FRANCIS LIBERMANN CATHOLIC HIGH SCHOOL Chemistry Unit – Avogadro Constant & the Mole – Science Department

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6. Thinking: A balloon is filled with 0.50 mol of helium. How many atoms of helium are in the balloon?

7. Thinking: A sample of benzene, C6H6, contains 5.69 mol. a.) How many molecules are in the sample?

b.) How many hydrogen atoms are in the sample?

8. Thinking: Aluminum oxide, Al2O3, forms a thin coating on aluminum when aluminum is exposed to the oxygen in the air. Consider a sample made up of 1.17 mol of aluminum oxide. a.) How many molecules are in the sample?

b.) How many atoms are in the sample?

c.) How many oxygen atoms are in the sample?

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FRANCIS LIBERMANN CATHOLIC HIGH SCHOOL Chemistry Unit â&#x20AC;&#x201C; Avogadro Constant & the Mole â&#x20AC;&#x201C; Science Department

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9. Communication: Why do you think chemists chose to define the mole the way they did? __________________________________________________________________________________ __________________________________________________________________________________ __________________________________________________________________________________ __________________________________________________________________________________ 10. Thinking: A sample of zinc oxide, ZnO, contains 3.28×1024 molecules of zinc oxide. A sample of zinc metal contains 2.78 mol of zinc atoms. Which sample contains more zinc: the compound or the element?

11. Thinking: Complete the following table. Use this table to help you understand the concept of using the Avogadro constant with smaller numbers 1 Dozen

1 mole

2 moles

3.5 moles

Li=

Cl=

H 2O

LiClO3

C6H12O6

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FRANCIS LIBERMANN CATHOLIC HIGH SCHOOL Chemistry Unit – Avogadro Constant & the Mole – Science Department

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11. Thinking: Complete the following table. Use this table to help you understand the concept of using the Avogadro constant with smaller numbers 1 Dozen

2 Dozen

1 mole

2 moles

3.5 moles

Li=

Cl=

H 2O

LiClO3

C6H12O6

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FRANCIS LIBERMANN CATHOLIC HIGH SCHOOL Chemistry Unit – Avogadro Constant & the Mole – Science Department

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Molar Mass – Understanding Concepts Communication 1. Draw a diagram that shows the relationship between the atomic mass and molar mass of an element and the Avogadro constant.

Thinking 2. Consider a 78.6 g sample of ammonia, NH3. a.) How many moles of ammonia are in the sample?

b.) How many molecules of ammonia are in the sample?

3. Use your understanding of the mole to answer the following questions. a.) What is the average mass, in grams, of a single atom of silicon, Si?

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FRANCIS LIBERMANN CATHOLIC HIGH SCHOOL Chemistry Unit – Molar Mass – Science Department

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4. Consider a 0.789 mol sample of sodium chloride, NaCl. a.) What is the mass of the sample?

b.) How many formula units of sodium chloride are in the sample?

c.) How many ions are in the sample?

5. A 5.00 carat diamond has a mass of 1.00 g. How many carbon atoms are in a 5.00 carat diamond?

6. A bottle of mineral supplement tablets contains 100 tablets and 200 mg of copper. The copper is found in the form of cupric oxide. What mass of cupric oxide is contained in each tablet?

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FRANCIS LIBERMANN CATHOLIC HIGH SCHOOL Chemistry Unit – Molar Mass – Science Department

Law of Conservation of Mass – Assignment KNOWLEDGE

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COMMUNICATION /9

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Communication Study the solution to the sample problem below then use the same approach to solve the practice problems below SAMPLEPROBLEM: A 137.1 g sample of silver bromide was found to contain 78.8 g of silver. (a) How much bromine was in the sample? (b) How much silver would there be in a 500 g sample of this compound? Here is the data from the problem, set out in a table. silver bromide 137.1 g 500.0 g

sample (a) sample (b)

silver 78.8 g yg

bromine xg zg

The problem solution requires finding the values of x and y. You can also find z. (a) Use conservation of mass to find x = 137.1 g – 78.8 g = 58.3 g. (b) Since the proportions are the same in the two samples, we can write

137.1 g 500.0 g

78.8 g y

, which gives y = 287.4 g

Thus, the first sample contained 58.3 g of bromine, and 500.0 g of silver bromide would contain 287.4 g of silver.

Practice Problems 1. A 45.6 g sample of zinc sulfide was found to contain 30.6 g of zinc. Find the masses of zinc and sulfur contained in 250.0 g of zinc sulfide. (3 marks)

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2. 39.5 g of cobalt will combine with 107.0 g of bromine to form a binary compound, A. How much of compound A can be formed from the reaction of 250.0 g of cobalt with sufficient bromine? (3 marks)

3. Analysis of 24.1 g of calcium oxide revealed that it contained 17.2 g of calcium. What mass of this compound would contain 60.0 g of calcium? (3 marks)

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FRANCIS LIBERMANN CATHOLIC HIGH SCHOOL Chemistry Unit – Law of Conservation of Mass – Science Department

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Percent Composition – Understanding Concepts Communication 1. Communication: Acetylene, C2H2, is the fuel in a welder’s torch. It contains an equal number of carbon and hydrogen atoms. Explain why acetylene is not 50% carbon by mass. _________________________________________________________________________________ _________________________________________________________________________________ _________________________________________________________________________________ 2. Knowledge: When determining percentage composition, why is it acceptable to work with either molar quantities, expressed in grams, or average molecular (or atomic or formula unit) quantities, expressed in atomic mass units?

3. Thinking: Indigo, C16H10N2O2, is the common name of the dye that gives blue jeans their characteristic colour. Calculate the mass of oxygen in 25.0 g of indigo.

4. Thinking: Potassium perchlorate, KClO4, is used extensively in explosives. Calculate the mass of oxygen in a 24.5 g sample of potassium perchlorate.

5. Thinking: 18.4 g of silver oxide, Ag2O, is decomposed into silver and oxygen by heating. What mass of silver will be produced?

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FRANCIS LIBERMANN CATHOLIC HIGH SCHOOL Chemistry Unit – Percent Composition – Science Department

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6. Application: The label on a box of baking soda (sodium hydrogen carbonate, NaHCO3) claims that there are 137 mg of sodium per 0.500 g of baking soda. Comment on the validity of this claim.

7. Thinking: A typical soap molecule consists of a polyatomic anion associated with a cation. The polyatomic anion contains hydrogen, carbon, and oxygen. One particular soap molecule has 18 carbon atoms. It contains 70.5% carbon, 11.5% hydrogen, and 10.4% oxygen by mass. It also contains one alkali metal cation. Identify the cation.

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FRANCIS LIBERMANN CATHOLIC HIGH SCHOOL Chemistry Unit – Percent Composition – Science Department

oxygen. One particular soap molecule has 18 carbon atoms. It contains 70.5% carbon, 11.5% hydrogen, and 10.4% oxygen by mass. It also contains onedate: alkali metal cation. Identify the cation.

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I Examine the photographs below. When concentrated sulfuric acid of acid pure carbon is formed, as is added to sucrose, 12H22O11 , a column Thinking: Examine the photographs below. When Cconcentrated sulfuric is added to sucrose, well as some water vapour and other gases. How would you find the C12H22O11, a column of pure carbon is formed, as well as some water vapour and other gases. How percent in of sucrose carbon in sucrose this reaction? may that all the would you find the mass percentmass of carbon using this using reaction? You mayYou assume assume that all the carbon in the sucrose is converted to carbon. carbon in the sucrose is converted to carbon. Design an experiment to determine the mass percent of Design an experiment to determine the mass percent of carbon in carbon in sucrose, based on this reaction. Do not try to perform this experiment. What difficulties sucrose, based on this reaction. Do not try to perform this experiment. might you encounter? What difficulties might you encounter?

_________________________________________________________________________________ _________________________________________________________________________________ _________________________________________________________________________________ _________________________________________________________________________________ _________________________________________________________________________________ _________________________________________________________________________________ _________________________________________________________________________________ _________________________________________________________________________________ _________________________________________________________________________________ 206 MHR • Unit 2 Chemical Quantities

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FRANCIS LIBERMANN CATHOLIC HIGH SCHOOL Chemistry Unit – Percent Composition – Science Department

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Empirical Formulas of Compounds – Understanding Concepts 1. Knowledge: a.) Why is the empirical formula of a compound also referred to as its simplest formula?

b.) Explain how the empirical formula of a compound is related to its molecular formula.

2. Thinking: Methyl salicylate, or oil of wintergreen, is produced by the wintergreen plant. It can also be prepared easily in a laboratory. Methyl salicylate is 63.1% carbon, 5.31% hydrogen, and 31.6% oxygen. Calculate the empirical formula of methyl salicylate.

3. Thinking: Determine the empirical formula of the compound that is formed by each of the following reactions. a.) 0.315 mol chlorine atoms react completely with 1.1 mol oxygen atoms

b.) 4.90 g silicon react completely with 24.8 g chlorine

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FRANCIS LIBERMANN CATHOLIC HIGH SCHOOL Chemistry Unit – Empirical Formulas – Science Department

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4. Thinking: Muscle soreness from physical activity is caused by a buildup of lactic acid in muscle tissue. Analysis of lactic acid reveals it to be 40.0% carbon, 6.71% hydrogen, and 53.3% oxygen by mass. Calculate the empirical formula of lactic acid.

5. Application: Imagine that you are a lawyer. You are representing a client charged with possession of a controlled substance. The prosecutor introduces, as forensic evidence, the empirical formula of the substance that was found in your client’s possession. How would you deal with this evidence as a lawyer for the defence? _________________________________________________________________________________ _________________________________________________________________________________ _________________________________________________________________________________ _________________________________________________________________________________ 6. Thinking: Olive oil is used widely in cooking. Oleic acid, a component of olive oil, contains 76.54% carbon, 12.13% hydrogen and 11.33% oxygen by mass. What is the empirical formula of oleic acid?

7. Thinking: Phenyl valerate is a colourless liquid that is used as a flavour and odorant. It contains 74.13% carbon, 7.92% hydrogen and 17.95% oxygen by mass. Determine the empirical formula of phenyl valerate.

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FRANCIS LIBERMANN CATHOLIC HIGH SCHOOL Chemistry Unit – Empirical Formulas – Science Department

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8. Thinking: Ferrocene is the common name given to a unique compound that consists of one iron atom sandwiched between two rings containing hydrogen and carbon. This orange, crystalline solid is added to fuel oil to improve combustion efficiency and eliminate smoke. As well, it is used as an industrial catalyst and a high-temperature lubricant. a.) Elemental analysis reveals ferrocene to be 64.56% carbon, 5.42% hydrogen and 30.02% iron by mass. Determine the empirical formula of ferrocene.

b.) Read the description of ferrocene carefully. Does this description provide enough information for you to determine the molecular formula of ferrocene? Explain your answer.

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FRANCIS LIBERMANN CATHOLIC HIGH SCHOOL Chemistry Unit â&#x20AC;&#x201C; Empirical Formulas â&#x20AC;&#x201C; Science Department

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Molecular Formulas of Compounds – Understanding Concepts 1. Knowledge: Explain the role that a mass spectrometer plays in determining the molecular formula of an unknown compound. _________________________________________________________________________________ _________________________________________________________________________________ _________________________________________________________________________________ _________________________________________________________________________________ 2. Thinking: Tartaric acid, also known as cream of tartar, is used in baking. Its empirical formula is C2H3O3. If 1.00 mol of tartaric acid contains 3.61×1024 oxygen atoms, what is the molecular formula of tartaric acid?

3. Application: Why is the molecular formula of a compound much more useful to a forensic scientist than the empirical formula of the compound? _________________________________________________________________________________ _________________________________________________________________________________ _________________________________________________________________________________ _________________________________________________________________________________

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FRANCIS LIBERMANN CATHOLIC HIGH SCHOOL Chemistry Unit –Molecular Formulas – Science Department

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4. Knowledge: Vinyl acetate, C4H6O2, is an important industrial chemical. It is used to make some of the polymers in products such as adhesives, paints, computer discs, and plastic films. a.) What is the empirical formula of vinyl acetate?

b.) How does the molar mass of vinyl acetate compare with the molar mass of its empirical formula?

5. Thinking: A compound has the formula C6xH5xOx, where x is a whole number. Its molar mass is 186 g/mol; what is its molecular formula?

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FRANCIS LIBERMANN CATHOLIC HIGH SCHOOL Chemistry Unit â&#x20AC;&#x201C;Molecular Formulas â&#x20AC;&#x201C; Science Department

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Carbon-Hydrogen Combustion Analyzer & Hydrate Compounds Understanding Concepts 1. Knowledge: Many compounds that contain carbon and hydrogen also contain nitrogen. Can you find the nitrogen content by carbon-hydrogen analysis, if the nitrogen does not interfere with the combustion reaction? If so, explain how. If not, explain why not. _________________________________________________________________________________ _________________________________________________________________________________ _________________________________________________________________________________ _________________________________________________________________________________ 2. Thinking: What would be the mass of a bag of anhydrous magnesium sulfate, MgSO4, if it contained the same amount of magnesium as a 1.00 kg bag of Epsom salts, MgSO4!7H2O? Give your answer in grams.

3. Knowledge: A compound that contains carbon, hydrogen, chlorine, and oxygen is subjected to carbon-hydrogen analysis. Can the mass percent of oxygen in the compound be determined using this method? Explain your answer. _________________________________________________________________________________ _________________________________________________________________________________ _________________________________________________________________________________ _________________________________________________________________________________ _________________________________________________________________________________ _________________________________________________________________________________

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FRANCIS LIBERMANN CATHOLIC HIGH SCHOOL Chemistry Unit – Carbon-Hydrogen Combustion Analyzer – Science Department

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4. Communication: Imagine that you are an analytical chemist. You are presented with an unknown compound, in the form of a white powder, for analysis. Your job is to determine the molecular formula of the compound. Create a flow chart that outlines the questions that you would ask and the analyses you would carry out. Briefly explain why each question or analysis is needed.

5. Application: A carbon-hydrogen analyzer uses a water absorber (which contains magnesium perchlorate, Mg(ClO4)2) and a carbon dioxide absorber (which contains sodium hydroxide, NaOH). The water absorber is always located in front of the carbon dioxide absorber. What does this suggest about the sodium hydroxide that is contained in the CO2 absorber? _________________________________________________________________________________ _________________________________________________________________________________ _________________________________________________________________________________ _________________________________________________________________________________

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FRANCIS LIBERMANN CATHOLIC HIGH SCHOOL Chemistry Unit – Carbon-Hydrogen Combustion Analyzer – Science Department

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6. Thinking: A hydrate of zinc nitrate has the formula Zn(NO3)2!xH2O. If the mass of 1.00 mol of anhydrous zinc nitrate is 63.67% of the mass of 1.00 mol of the hydrate, what is the value of x?

7. Knowledge: A 2.524 g sample of a compound contains carbon, hydrogen, and oxygen. The sample is subjected to carbon-hydrogen analysis. 3.703 g of carbon dioxide and 1.514 g of water are collected. a.) Determine the empirical formula of the compound.

b.) If one molecule of the compound contains 12 atoms of hydrogen, what is the molecular formula of the compound?

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FRANCIS LIBERMANN CATHOLIC HIGH SCHOOL Chemistry Unit – Carbon-Hydrogen Combustion Analyzer – Science Department

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Stoichiometry Problems – Practice Questions KNOWLEDGE

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Ammonia (NH3) can be produced by the reaction of Li3N and water. A by-product of the reaction is lithium hydroxide (LiOH). (a) Write the balanced chemical equation for this reaction.

(b) Write the ratio of Li3N molecules: H2O molecules: LiOH molecules: NH3 molecules.

(d) How many moles of lithium hydroxide will be produced if 1.27 moles of Li3N are reacted with excess water?

(e) How much Li3N is required to react with excess water to produce 35.4 g of NH3?

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FRANCIS LIBERMANN CATHOLIC HIGH SCHOOL Chemistry Unit – Stoichiometry – Science Department

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Particle Relationships in Chemical Equations – Assignment KNOWLEDGE

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Communication 1. Balance the following equations and state the type of reaction shown. BALANCE

REACTION TYPE

a.) ____NaClO3 → ____NaCl + ____O2

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b.) ____K2O + ____H2O → ____KOH

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c.) ____KOH + ____HBr → ____H2O + ____KBr

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d) ____C2H2 + ____Br2 → ____C2H2Br2

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e) ____NaI + ____Cl2 → ____NaCl + ____I2

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2. a.) Balance the following equation: ____Mg(OH)2 + ____HNO3 → ____Mg(NO3)2 + ____H2O

Products Atom Type

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Reactants

Number of Atoms

Atom Type

NO3

NO3 THINKING

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Number of Atoms

FRANCIS LIBERMANN CATHOLIC HIGH SCHOOL Chemistry Unit – Ratio of Atoms – Science Department

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b.) Write the ratio of Mg(OH)2 formula units to HNO3 molecules.

c.) Write the ratio of Mg(NO3)2 formula units to H2O molecules.

d.) How many molecules of water are formed if there are 4000 formula units of Mg(OH)2 initially?

Use the format shown below to help you solve this equation.

e.) Where does the information for the known ratio come from? How about the information for the unknown ratio?

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FRANCIS LIBERMANN CATHOLIC HIGH SCHOOL Chemistry Unit – Ratio of Atoms – Science Department

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Stoichiometry – Understanding Concepts 1. Knowledge: Why is a balanced chemical equation needed to solve stoichiometric calculations?

2. Knowledge: Sulfur and oxygen can combine to form sulfur dioxide and sulfur trioxide. a.) Write a balanced chemical equation for the formation of sulfur dioxide from S and O2.

b.) Write a balanced chemical equation for the formation of sulfur trioxide.

c.) How many moles of oxygen must react with 1.0 mol of S to form 1.0 mol of sulfur trioxide?

d.) What mass of oxygen is needed to react with 32.1 g of S to form sulfur trioxide?

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FRANCIS LIBERMANN CATHOLIC HIGH SCHOOL Chemistry Unit – Stoichiometry – Science Department

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3. Knowledge: For the following questions look at the complete combustion reaction of propane a.) Write a balanced chemical equation for the complete combustion reaction of propane.

b.) Write the mole ratios for the reactants and products in the combustion of propane.

c.) How many moles of oxygen are needed to react with 0.500 mol of propane?

d.) How many molecules of oxygen are needed to react with 2.00 mol of propane?

e.) If 3.00 mol of propane burn completely in oxygen, how many moles of gas are produced?

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FRANCIS LIBERMANN CATHOLIC HIGH SCHOOL Chemistry Unit – Stoichiometry – Science Department

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4. Thinking: Phosphorus pentachloride, reacts with water to form phosphoric acid and hydrochloric acid. a.) What mass of phosphorus pentachloride is needed to react with an excess quantity of water to produce 23.5 g of phosphoric acid?

b.) How many molecules of water are needed to react with 3.87 g of phosphorus pentachloride?

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FRANCIS LIBERMANN CATHOLIC HIGH SCHOOL Chemistry Unit – Stoichiometry – Science Department

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5. Thinking: A chemist has a beaker containing lead (II) nitrate, dissolved in water. The chemist adds a solution containing sodium iodide and a bright yellow precipitate is formed. The chemist continues to add sodium iodide until no further yellow precipitate is formed. The chemist filters the precipitate, dries it in an oven, and finds it has a mass of 1.43 g. a.) Write a balanced chemical equation to describe what happened in this experiment. Hint: compounds with sodium ions are always soluble.

b.) Use the balanced chemical equation to determine what mass of lead nitrate was dissolved in the water in the beaker.

6. Application: The Apollo-13 mission overcame an astonishing number of difficulties on its return to Earth. One problem the astronauts encountered was removing carbon dioxide from the air they were breathing. Do some research to find out: a.) What happened to lead to an unexpected accumulation of carbon dioxide? _____________________________________________________________________________ _____________________________________________________________________________ _____________________________________________________________________________ _____________________________________________________________________________ _____________________________________________________________________________ b.) What did the astronauts do to overcome this difficulty? _____________________________________________________________________________ _____________________________________________________________________________ _____________________________________________________________________________ KNOWLEDGE

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FRANCIS LIBERMANN CATHOLIC HIGH SCHOOL Chemistry Unit â&#x20AC;&#x201C; Stoichiometry â&#x20AC;&#x201C; Science Department

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Stoichiometry – Practice Problems KNOWLEDGE

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Thinking 1. Aluminum carbide, Al4C3, is a yellow powder that reacts with water to produce aluminum hydroxide and methane. What mass of water is required to react completely with 25.0 g of aluminum carbide?

2. Iron (III) oxide, also known as rust, can be removed from iron by reacting it with hydrochloric acid to produce iron (III) chloride and water. What mass of hydrochloric acid is required to react with 1.00×102 g of rust?

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FRANCIS LIBERMANN CATHOLIC HIGH SCHOOL Chemistry Unit – Stoichiometry – Science Department

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3. Powdered zinc reacts rapidly with powdered sulfur (S8) in a highly exothermic reaction to produce zinc sulfide. What mass of zinc sulfide is expected when 32.0 g of sulfur reacts with sufficient zinc?

4. Iron reacts slowly with hydrochloric acid to produce iron (II) chloride and hydrogen gas. What mass of HCl is required to react with 3.56 g of iron?

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FRANCIS LIBERMANN CATHOLIC HIGH SCHOOL Chemistry Unit – Stoichiometry – Science Department

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5. Dinitrogen pentoxide is a white solid. When heated it decomposes to produce nitrogen dioxide and oxygen. How many grams of oxygen gas will be produced in this reaction when 2.34 g of nitrogen dioxide are made?

6. Ammonium sulfate is used as a source of nitrogen in some fertilizers. It reacts with sodium hydroxide. What mass of sodium hydroxide is required to react completely with 15.4 g of ammonium sulfate?

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FRANCIS LIBERMANN CATHOLIC HIGH SCHOOL Chemistry Unit – Stoichiometry – Science Department

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7. The addition of concentrated hydrochloric acid to manganese (IV) oxide leads to the production of chlorine gas, MnCl2 and water. What mass of chlorine can be obtained when 4.76×10–2 g of hydrochloric acid reacts with sufficient manganese (IV) oxide? ____ HCl(aq) + ____ MnO2(g)  ____ MnCl2(aq) + ____ Cl2(g) + ____ H2O(l)

8. Magnesium oxide reacts with phosphoric acid to produce magnesium phosphate and water. How many grams of magnesium oxide are required to react completely with 33.5 g of phosphoric acid?

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FRANCIS LIBERMANN CATHOLIC HIGH SCHOOL Chemistry Unit – Stoichiometry – Science Department

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9. The thermal decomposition of ammonium dichromate is an impressive reaction. When heated with a Bunsen burner or propane torch, the orange crystals of ammonium dichromate slowly decompose to green chromium (III) oxide in a volcano-like display. Colourless nitrogen gas and water vapour are also given off. a.) Calculate the number of molecules of chromium (III) oxide that is produced from the decomposition of 10.0 g of ammonium dichromate.

b.) In a different reaction, 16.9 g of nitrogen gas is produced when a sample of ammonium dichromate decomposed. How many water molecules are also produced in this reaction?

c.) How many formula units of ammonium dichromate are needed to produce 1.45 g of H2O?

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FRANCIS LIBERMANN CATHOLIC HIGH SCHOOL Chemistry Unit â&#x20AC;&#x201C; Stoichiometry â&#x20AC;&#x201C; Science Department

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10. Ammonia gas reacts with oxygen to produce water and nitrogen oxide. This reaction can be catalyzed, or sped up, by Cr2O3 , as produced by the decomposition reaction of ammonium dichromate. a.) How many molecules of oxygen are required to react with 34.0 g of ammonia?

b.) What mass of nitrogen oxide is expected from the reaction of 8.95×1024 molecules of oxygen with

sufficient ammonia?

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FRANCIS LIBERMANN CATHOLIC HIGH SCHOOL Chemistry Unit – Stoichiometry – Science Department

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Limiting Reactants – Practice Problems KNOWLEDGE

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Thinking 1. 3.76 g of zinc reacts with 8.93×1023 molecules of hydrogen chloride. Which reactant is present in excess?

2. Aluminum with copper (II) chloride. If 0.25 g of aluminum reacts with 0.51 g of copper (II) chloride, determine the limiting reactant.

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FRANCIS LIBERMANN CATHOLIC HIGH SCHOOL Chemistry Unit – Limiting reactants – Science Department

2011 -11 -26 00:41:09

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2.7.02.2 - Limiting Reactants Practice Questions with Space Answers.pdf (#4)

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3. Hydrogen fluoride, HF, is a highly toxic gas. It is produced by the double displacement reaction of calcium fluoride reacting with concentrated sulfuric acid. Determine the limiting reactant when 10.0 g of calcium fluoride reacts with 15.5 g of sulfuric acid.

4. Acrylic, a common synthetic fibre, is formed from acrylonitrile, C3H3N. Acrylonitrile can be prepared by the reaction of propylene, C3H6, with nitric oxide, NO. Two other products formed are water and nitrogen gas. What is the limiting reactant when 126 g of propylene reacts with 175 g of nitric oxide?

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FRANCIS LIBERMANN CATHOLIC HIGH SCHOOL Chemistry Unit – Limiting reactants – Science Department

2011 -11 -26 00:41:11

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5. Hydrazine, N2H4, reacts exothermically with hydrogen peroxide to produce nitric acid and water. a.) 120.0 g of hydrazine reacts with an equal mass of hydrogen peroxide. Which is the limiting reactant?

b.) What mass of nitric acid is expected?

c.) What mass, in grams, of the excess reactant remains at the end of the reaction?

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FRANCIS LIBERMANN CATHOLIC HIGH SCHOOL Chemistry Unit – Limiting reactants – Science Department

2011 -11 -26 00:41:12

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6. In the textile industry, chlorine is used to bleach fabrics. Any of the toxic chlorine that remains after the bleaching process is destroyed by reacting it with a sodium thiosulfate solution. ____ Na2S2O3(aq) + ____ Cl2(g) + ____ H2O(l)  ____ NaHSO4(aq) + ____ HCl(aq) 135 kg of sodium thiosulfate reacts with 50.0 kg of chlorine and 238 kg of water. How many grams of sodium hydrogen sulfate are expected?

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FRANCIS LIBERMANN CATHOLIC HIGH SCHOOL Chemistry Unit – Limiting reactants – Science Department

2011 -11 -26 00:41:13

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7. Manganese (III) fluoride can be formed by the reaction of manganese(II) iodide with fluorine. Another product formed is liquid iodine pentafluoride. a.) 1.23 g of manganese (II) iodide reacts with 25.0 g of fluorine. What mass of manganese (III) fluoride is expected?

b.) How many molecules of iodine pentafluoride is produced in part a.)?

c.) What reactant is in excess? How much of it remains at the end of the reaction?

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FRANCIS LIBERMANN CATHOLIC HIGH SCHOOL Chemistry Unit – Limiting reactants – Science Department

2011 -11 -26 00:41:15

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8. Carbon disulfide is used as a solvent for water-insoluble compounds, such as fats, oils, and waxes. Calculate the mass of carbon disulfide that is produced when 17.5 g of carbon reacts with 225 g of sulfur dioxide. Another product formed is carbon oxide.

9. Aqueous solution of ferric sulfate with aqueous sodium hydroxide. What mass of ferric hydroxide is produced when 10.0 g of ferric sulfate reacts with an equal mass of sodium hydroxide?

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FRANCIS LIBERMANN CATHOLIC HIGH SCHOOL Chemistry Unit – Limiting reactants – Science Department

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2.7.02.2 - Limiting Reactants Practice Questions with Space Answers.pdf (6/6)

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Percentage Yield – Practice Problems KNOWLEDGE

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Thinking 1. 20.0 g of bromic acid, HBrO3 , is reacted with excess hydrobromic acid to form water and bromine. a.) What is the theoretical yield of bromine for this reaction?

b.) If 47.3 g of bromine is produced, what is the percentage yield of bromine?

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FRANCIS LIBERMANN CATHOLIC HIGH SCHOOL Chemistry Unit – Percentage Yield – Science Department

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2. Aqueous barium nitrate reacts with sodium sulfate. When 35.0 g of barium nitrate is reacted with excess sodium sulfate, 29.8 g of precipitate is recovered by the chemist. a.) Calculate the theoretical yield of the precipitate.

b.) Calculate the percentage yield of precipitate.

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FRANCIS LIBERMANN CATHOLIC HIGH SCHOOL Chemistry Unit – Percentage Yield – Science Department

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3. Yeasts can act on a sugar, such as glucose to produce ethyl alcohol, C2H5OH, and carbon dioxide. If 223 g of ethyl alcohol are recovered after 1.63 kg of glucose react, what is the percentage yield of the reaction?

4. The following reaction proceeds with a 70% yield. ____ C6H6(l) + ____ HNO3(aq)  ____ C6H5NO2(l) + ____ H2O(l) Calculate the mass of C6H5NO2 expected if 12.8 g of C6H6 reacts with excess HNO3.

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FRANCIS LIBERMANN CATHOLIC HIGH SCHOOL Chemistry Unit – Percentage Yield – Science Department

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5. Marble is made primarily of calcium carbonate. When calcium carbonate reacts with hydrogen chloride, it reacts to form calcium chloride, carbon dioxide and water. If this reaction occurs with 81.5% yield, what mass of carbon dioxide will be collected if 15.7 g of calcium carbonate is added to sufficient hydrogen chloride?

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FRANCIS LIBERMANN CATHOLIC HIGH SCHOOL Chemistry Unit – Percentage Yield – Science Department