## 3 STOICHIOMETRY: CALCULATIONS v CHEMICAL FORMULAS and EQUATIONS

### EXERCISES

VISUALIZING CONCEPTS

3.1 The reaction in between reactant A (blue spheres) and also reactant B (red spheres) is shown in the following diagram: Based top top this diagram, i beg your pardon equation best describes the reaction?

(a) A2 + B → A2B

(b) A2 + 4 B → 2 AB2

(c) 2 A + B4 → 2 AB2

(d) A + B2 → AB2

3.2 Under appropriate experimental conditions, H2 and also CO undergo a mix reaction to form CH3OH. The following drawing represents a sample the H2. Do a matching drawing of the CO essential to react fully with the H2. Just how did you come at the number of CO molecules in her drawing? 3.3 The adhering to diagram to represent the repertoire of aspects formed through a decomposition reaction. (a) If the blue spheres represent N atoms and the red ones represent O atoms, what was the empirical formula of the original compound? (b) could you draw a diagram representing the molecule of the compound that had actually been decomposed? Why or why not? 3.4 The complying with diagram to represent the collection of CO2 and H2O molecules created by complete burning of a hydrocarbon. What is the empirical formula the the hydrocarbon? 3.5 Glycine, one amino acid used by organisms to do proteins, is represented by the complying with molecular model.

You are watching: How many moles of thc does this 27 μg represent?

(a) write its molecular formula.

(b) identify its molar mass.

(c) calculation the massive of 3 mole of glycine.

(d) calculation the percent nitrogen by massive in glycine. 3.6 The following diagram represents a high-temperature reaction between CH4 and H2O. Based on this reaction, how numerous moles of every product deserve to be obtained beginning with 4.0 mol CH4? 3.7 Nitrogen (N2) and also hydrogen (H2) reaction to kind ammonia (NH3). Think about the mixture the N2 and H2 displayed in the accompanying diagram. The blue spheres represent N, and also the white ones represent H. Attract a representation of the product mixture, assuming that the reaction goes come completion. Just how did you arrive at her representation? What is the limiting reactant in this case? 3.8 Nitrogen monoxide and also oxygen react to type nitrogen dioxide. Take into consideration the mixture of NO and O2 displayed in the accompanying diagram. The blue spheres stand for N, and also the red ones represent O. (a) attract a depiction of the product mixture, assuming the the reaction goes to completion. What is the limiting reactant in this case? (b) How plenty of NO2 molecules would you draw as assets if the reaction had actually a percent yield of 75%? BALANCING chemical EQUATIONS (section 3.1)

3.9 (a) What clinical principle or regulation is offered in the process of balancing chemical equations? (b) In balancing equations, why must you not adjust subscripts in chemistry formulas? (c) how would you write out fluid water, water vapor, aqueous salt chloride, and solid sodium chloride in chemical equations?

3.10 (a) What is the difference between adding a subscript 2 come the end of the formula because that CO to offer CO2 and adding a coefficient in prior of the formula to offer 2 CO? (b) Is the complying with chemical equation, as written, continual with the law of conservation of mass?

3 Mg(OH)2(s) + 2 H3PO4(aq) → Mg3(PO4)2(s) + 6 H2O(l)

Why or why not?

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3.11 Balance the following equations:

(a) CO(g) + O2(g) → CO2(g)

(b) N2O5(g) + H2O(l) → HNO3(aq)

(c) CH4(g) + Cl2(g) → CCl4(l) + HCl(g)

(d) Al4C3(s) + H2O(l) → Al(OH)3(s) + CH4(g)

(e) C5H10O2(l) + O2(g) → CO2(g) + H2O(g)

(f) Fe(OH)3(s) + H2SO4(aq) → Fe2(SO4)3(aq) + H2O(l)

(g) Mg3N2(s) + H2SO4(aq) → MgSO4(aq) + (NH4)2SO4(aq)

3.12 Balance the complying with equations:

(a) Li(s) + N2(g) → Li3N(s)

(b) TiCl4(l) + H2O(l) → TiO2(s) + HCl(aq)

(c) NH4NO3(s) → N2(g) + O2(g) + H2O(g)

(d) Ca3P2(s) + H2O(l) → Ca(OH)2(aq) + PH3(g)

(e) Al(OH)3(s) + H2SO4(aq) → Al2(SO4)3(aq) + H2O(l)

(f) AgNO3(aq) + Na2CO3(aq) → Ag2NO3(s) + Na2CO3(aq)

(g) C2H5NH2(g) + O2(g) → CO2(g) + H2O(g) + N2(g)

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3.13 Write well balanced chemical equations to exchange mail to each of the adhering to descriptions: (a) heavy calcium carbide, CaC2, reacts through water to type an aqueous systems of calcium hydroxide and acetylene gas, C2H2. (b) as soon as solid potassium chlorate is heated, that decomposes to form solid potassium chloride and oxygen gas. (c) heavy zinc steel reacts v sulfuric mountain to form hydrogen gas and an aqueous equipment of zinc sulfate. (d) when liquid phosphorus trichloride is included to water, it reaction to kind aqueous phosphorous acid, H3PO3(aq), and aqueous hydrochloric acid. (e) once hydrogen sulfide gas is passed over solid hot iron(III) hydroxide, the resultant reaction produces solid iron(III) sulfide and gaseous water.

3.14 Write balanced chemical equations to exchange mail to every of the complying with descriptions: (a) as soon as sulfur trioxide gas reacts through water, a solution of sulfuric acid forms. (b) Boron sulfide, B2S3(s), reacts violently with water to type dissolved boric acid, H3BO3, and also hydrogen sulfide gas. (c) Phosphine, PH3(g), combusts in oxygen gas to kind water vapor and solid tetraphosphorus decaoxide. (d) once solid mercury(II) nitrate is heated, that decomposes to form solid mercury(II) oxide, gas nitrogen dioxide, and oxygen. (e) Copper metal reacts through hot focused sulfuric acid solution to form aqueous copper(II) sulfate, sulfur dioxide gas, and also water.

PATTERNS OF chemistry REACTIVITY (section 3.2)

3.15 (a) once the metallic element sodium combines with the nonmetallic aspect bromine, Br2(l), how deserve to you determine the chemistry formula the the product? exactly how do you recognize whether the product is a solid, liquid, or gas in ~ room temperature? compose the well balanced chemical equation for the reaction. (b) when a hydrocarbon burns in air, what reactant besides the hydrocarbon is affiliated in the reaction? What commodities are formed? create a well balanced chemical equation because that the burning of benzene, C6H6(l), in air.

3.16 (a) recognize the chemistry formula of the product created when the metallic facet aluminum combines through the non-metallic element bromine, Br2. Create the balanced chemical equation because that the reaction. (b) What products form when a link containing C, H, and O is fully combusted in air? write a balanced chemical equation for the burning of acetone, C3H6O(l), in air.

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3.17 write a balanced chemical equation for the reaction that occurs when (a) Mg(s) reacts v Cl2(g); (b) barium carbonate decomposes into barium oxide and carbon dioxide gas when heated; (c) the hydrocarbon styrene, C8H8(l), is combusted in air; (d) dimethylether, CH3OCH3(g), is combusted in air.

3.18 create a balanced chemical equation because that the reaction that occurs as soon as (a) calcium metal undergoes a mix reaction v O2(g); (b) copper(II) hydroxide decomposes into copper(II) oxide and water once heated; (c) heptane, C7H16(l), burns in air; (d) methyl tert-butyl ether, C5H12O(l), burns in air.

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3.19 Balance the complying with equations and also indicate even if it is they are combination, decomposition, or burning reactions:

(a) C3H6(g) + O2(g) → CO2(g) + H2O(g)

(b) NH4NO3(s) → N2O(g) + H2O(g)

(c) C5H6O(l) + O2(g) → CO2(g) + H2O(g)

(d) N2(g) + H2(g) → NH3(g)

(e) K2O(s) + H2O(l) → KOH(aq)

3.20 Balance the following equations and indicate whether they are combination, decomposition, or burning reactions:

(a) PbCO3(s) → PbO(s) + CO2(g)

(b) C2H4(g) + O2(g) → CO2(g) + H2O(g)

(c) Mg(s) + N2(g) → Mg3N2(s)

(d) C7H8O2(l) + O2(g) → CO2(g) + H2O(g)

(e) Al(s) + Cl2(g) → AlCl3(s)

FORMULA WEIGHTS (section 3.3)

3.21 identify the formula weights of every of the following compounds: (a) nitric acid, HNO3; (b) KMnO4; (c) Ca3(PO4)2; (d) quartz, SiO2; (e) gallium sulfide, (f) chromium(III) sulfate, (g) phosphorus trichloride.

3.22 determine the formula weights of each of the following compounds: (a) nitrous oxide, N2O, known as laughing gas and also used as an anesthetic in dentistry; (b) benzoic acid, HC7H5O2, a substance used as a food preservative; (c) Mg(OH)2, the active ingredient in milk that magnesia;(d) urea, (NH2)2CO, a compound provided as a nitrogen fertilizer; (e) isopentyl acetate, CH3CO2C5H11, responsible because that the odor of bananas.

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3.23 calculation the portion by massive of oxygen in the adhering to compounds: (a) morphine, C17H19NO3; (b) codeine, C18H21NO3(c) cocaine, C17H21NO4; (d) tetracycline, C22H24N2O8; (e) digitoxin, C41H64O13; (f) vancomycin, C66H75Cl2NO24.

3.24 calculation the percentage by mass of the indicated element in the following compounds: (a) carbon in acetylene, C2H2, a gas offered in welding; (b) hydrogen in ascorbic acid, HC6H7O6, likewise known as vitamin C; (c) hydrogen in ammonium sulfate, (NH4)2SO4, a substance offered as a nitrogen fertilizer; (d) platinum in PtCl2(NH3)2, a chemotherapy agent referred to as cisplatin; (e) oxygen in the mrs sex hormone estradiol, C18H24O2; (f) carbon in capsaicin, C18H27NO3, the link that gives the hot taste come chili peppers.

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3.25 based on the adhering to structural formulas, calculation the percent of carbon by mass present in each compound:  3.26 calculation the percentage of carbon by massive in every of the compounds represented by the adhering to models: AVOGADRO"S NUMBER and THE MOLE (section 3.4)

3.27 (a) What is Avogadro"s number, and also how is it regarded the mole? (b) What is the relationship in between the formula load of a substance and also its molar mass?

3.28 (a) What is the mass, in grams, of a mole of 12C? (b) How many carbon atoms are existing in a mole the 12C?

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3.29 without doing any detailed calculations (but making use of a periodic table to offer atomic weights), rank the following samples in stimulate of increasing number of atoms: 0.50 mol H2O, 23 g Na, 6.0 × 1023 N2 molecules.

3.30 without doing any detailed calculations (but utilizing a periodic table to offer atomic weights), rank the adhering to samples in bespeak of increasing variety of atoms: 9.0 × 1023 molecules of H2O2, 2.0 mol CH4, 16 g O2.

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3.31 What is the mass, in kilograms, of one Avogadro"s number of people, if the mean mass the a person is 160 lb? how does this compare with the fixed of Earth, 5.98 × 1024 kg?

3.32 If Avogadro"s variety of pennies is separated equally amongst the 300 million men, women, and also children in the joined States, how numerous dollars would certainly each receive? exactly how does this compare through the gross residential product (GDP) the the joined States, which to be \$14.4 trillion in 2008? (The GDP is the complete market value of the nation"s goods and services.)

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3.33 calculation the following quantities:

(a) mass, in grams, the 0.105 mole the sucrose (C12H22O11)

(b) mole of Zn(NO3)2 in 143.50 g the this substance

(c) number of molecules in 1.0 × 10−6 mol CH3CH2OH

(d) variety of N atom in 0.410 mol NH3

3.34 calculation the following quantities:

(a) mass, in grams, that 1.50 × 10−2 mol of CdS

(b) variety of moles of NH4Cl in 86.6 g that this substance

(c) variety of molecules in 8.447 × 10−2 mol C6H6

(d) variety of O atom in 6.25 × 10−3 mol Al(NO3)3

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3.35 (a) What is the mass, in grams, that 2.50 × 10−3 mol that ammonium phosphate?

(b) How many moles that chloride ions room in 0.2550 g the aluminum chloride?

(c) What is the mass, in grams, of 7.70 × 1020 molecule of caffeine, C8H10N4O2?

(d) What is the molar fixed of cholesterol if 0.00105 mol has a fixed of 0.406 g?

3.36 (a) What is the mass, in grams, that 1.223 mol of iron(III) sulfate?

(b) How numerous moles the ammonium ions space in 6.955 g the ammonium carbonate?

(c) What is the mass, in grams, of 1.50 × 1021 molecule of aspirin, C9H8O4?

(d) What is the molar fixed of diazepam (Valium®) if 0.05570 mol has a massive of 15.86 g?

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3.37 The molecular formula that allicin, the link responsible because that the characteristic smell of garlic, is C6H10OS2. (a) What is the molar massive of allicin? (b) How countless moles of allicin are existing in 5.00 mg the this substance? (c) How countless molecules of allicin are in 5.00 mg the this substance? (d) How many S atom are current in 5.00 mg of allicin?

3.38 The molecule formula of aspartame, the fabricated sweetener marketed as NutraSweet®, is C14H18N2O5. (a) What is the molar fixed of aspartame? (b) How numerous moles that aspartame are current in 1.00 mg the aspartame? (c) How countless molecules that aspartame are present in 1.00 mg the aspartame? (d) How many hydrogen atom are current in 1.00 mg that aspartame?

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3.39 A sample that glucose, C6H12O6, has 1.250 × 1021 carbon atoms. (a) How plenty of atoms the hydrogen does it contain? (b) How many molecules of glucose does the contain? (c) How many moles the glucose does that contain? (d) What is the massive of this sample in grams?

3.40 A sample that the masculine sex hormone testosterone, C19H28O2, has 3.88 × 1021 hydrogen atoms. (a) How many atoms that carbon does that contain? (b) How numerous molecules of testosterone does the contain? (c) How numerous moles that testosterone does it contain? (d) What is the fixed of this sample in grams?

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3.41 The allowable concentration level the vinyl chloride, C2H3Cl, in the setting in a chemical tree is 2.0 × 10−6 g/L. How countless moles the vinyl chloride in every liter walk this represent? How countless molecules every liter?

3.42 At the very least 25 μg that tetrahydrocannabinol (THC), the energetic ingredient in marijuana, is forced to create intoxication. The molecular formula the THC is C21H30O2. How numerous moles the THC go this 25 μg represent? How numerous molecules?

EMPIRICAL formulas (section 3.5)

3.43 give the empirical formula of every of the complying with compounds if a sample includes (a) 0.0130 mol C, 0.0390 mol H, and 0.0065 mol O; (b) 11.66 g iron and 5.01 g oxygen; (c) 40.0% C, 6.7% H, and 53.3% O by mass.

3.44 determine the empirical formula of each of the complying with compounds if a sample has (a) 0.104 mol K, 0.052 mol C, and 0.156 mol O; (b) 5.28 g Sn and 3.37 g F; (c) 87.5% N and 12.5% H by mass.

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3.45 determine the empirical formulas of the compounds v the following compositions through mass:

(a) 10.4% C, 27.8% S, and 61.7% Cl

(b) 21.7% C, 9.6% O, and also 68.7% F

(c) 32.79% Na, 13.02% Al, and also the remainder F

3.46 determine the empirical recipe of the compounds through the complying with compositions by mass:

(a) 55.3% K, 14.6% P, and 30.1% O

(b) 24.5% Na, 14.9% Si, and also 60.6% F

(c) 62.1% C, 5.21% H, 12.1% N, and the remainder O

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3.47 A compound whose empirical formula is XF3 is composed of 65% F by mass. What is the atomic mass that X?

3.48 The compound XCl4 consists of 75.0% Cl by mass. What is the aspect X?

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3.49 What is the molecular formula of every of the adhering to compounds?

(a) empirical formula CH2, molar fixed = 84 g/mol

(b) empirical formula NH2Cl, molar massive = 51.5 g/mol

3.50 What is the molecular formula of each of the adhering to compounds?

(a) empirical formula HCO2, molar massive = 90.0 g/mol

(b) empirical formula C2H4O, molar fixed = 88 g/mol

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3.51 recognize the empirical and molecular recipe of each of the following substances:

(a) Styrene, a link substance used to make Styrofoam® cups and also insulation, has 92.3% C and 7.7% H through mass and has a molar fixed of 104 g/mol.

(b) Caffeine, a stimulant uncovered in coffee, contains 49.5% C, 5.15% H, 28.9% N, and 16.5% O by mass and has a molar massive of 195 g/mol.

(c) Monosodium glutamate (MSG), a odor enhancer in certain foods, contains 35.51% C, 4.77% H, 37.85% O, 8.29% N, and 13.60% Na, and has a molar fixed of 169 g/mol.

3.52 recognize the empirical and also molecular formulas of each of the complying with substances:

(a) Ibuprofen, a headache remedy, contains 75.69% C, 8.80% H, and 15.51% O by mass, and also has a molar fixed of 206 g/mol.

(b) Cadaverine, a foul-smelling substance developed by the activity of bacteria on meat, contains 58.55% C, 13.81% H, and also 27.40% N through mass; that molar fixed is 102.2 g/mol.

(c) Epinephrine (adrenaline), a hormone secreted into the bloodstream in time of danger or stress, consists of 59.0% C, 7.1% H, 26.2% O, and also 7.7% N by mass; that MW is around 180 amu.

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3.53 (a) Combustion evaluation of toluene, a typical organic solvent, gives 5.86 mg the CO2 and 1.37 mg the H2O. If the compound includes only carbon and also hydrogen, what is its empirical formula? (b) Menthol, the substance we have the right to smell in mentholated sneeze drops, is created of C, H, and O. A 0.1005-g sample the menthol is combusted, developing 0.2829 g of CO2 and also 0.1159 g the H2O. What is the empirical formula for menthol? If menthol has actually a molar mass of 156 g/mol, what is its molecular formula?

3.54 (a) The characteristic smell of pineapple is because of ethyl butyrate, a compound containing carbon, hydrogen, and oxygen. Combustion of 2.78 mg of ethyl butyrate produce 6.32 mg the CO2 and 2.58 mg of H2O. What is the empirical formula that the compound? (b) Nicotine, a component of tobacco, is created of C, H, and N. A 5.250-mg sample of nicotine was combusted, producing 14.242 mg of CO2 and 4.083 mg the H2O. What is the empirical formula for nicotine? If nicotine has actually a molar fixed of 160 ± 5 g/mol, what is its molecular formula?

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3.55 Valproic acid, provided to act seizures and bipolar disorder, is created of C, H, and O. A 0.165-g sample is combusted in an apparatus such as that displayed in number 3.14. The get in massive of the H2O absorb is 0.166 g, whereas that of the CO2 absorb is 0.403 g. What empirical formula for valproic acid execute these results indicate? Is this empirical formula constant with the molecule model shown here? 3.56 Propenoic acid, as shown here, is a reactive organic liquid offered in the produce of plastics, coatings, and also adhesives. One unlabeled container is thought to save this acid. A 0.2033-g sample is combusted in an apparatus such together that shown in number 3.14. The obtain in mass of the H2O absorb is 0.102 g, whereas the of the CO2 absorb is 0.374 g. Is this analysis consistent v the contents of the container being propenoic acid? ______

3.57 Washing soda, a compound supplied to prepare hard water for washing laundry, is a hydrate, which method that a certain number of water molecule are included in the solid structure. Its formula deserve to be written as Na2CO3 • xH2O, wherein x is the variety of moles the H2O per mole that Na2CO3. When a 2.558-g sample of washing soda is heated in ~ 25 °C, every the water that hydration is lost, leave 0.948 g that Na2CO3. What is the worth of x?

3.58 Epsom salts, a solid laxative used in veterinarian medicine, is a hydrate, which means that a certain variety of water molecule are had in the hard structure. The formula for Epsom salts have the right to be created as MgSO4 • xH2O, whereby x indicates the number of moles the H2O per mole that MgSO4. As soon as 5.061 g of this hydrate is heated come 250 °C, every the water that hydration is lost, leaving 2.472 g of MgSO4. What is the worth of x?

CALCULATIONS based upon CHEMICAL EQUATIONS (section 3.6)

3.59 Why is it crucial to use well balanced chemical equations as soon as determining the quantity of a product formed from a provided quantity of a reactant?

3.60 What parts of balanced chemical equations offer information around the family member numbers of moles of reactants and also products involved in a reaction?

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3.61 Hydrofluoric acid, HF(aq), cannot be stored in glass bottles since compounds called silicates in the glass are struck by the HF(aq). Sodium silicate (Na2SiO3), because that example, reacts together follows:

Na2SiO3(s) + 8 HF(aq) → H2SiF6(aq) + 2 NaF(aq) + 3 H2O(l)

(a) How countless moles the HF are essential to react v 0.300 mol the Na2SiO3?

(b) How numerous grams of NaF form when 0.500 mol that HF reacts through excess Na2SiO3?

(c) How numerous grams that Na2SiO3 can react with 0.800 g the HF?

3.62 The reaction between potassium superoxide, KO2, and CO2,

4 KO2 + 2 CO2 → 2K2CO3 + 3 O2

is used as a resource of O2 and also absorber the CO2 in self-contained breathing devices used through rescue workers. (a) How numerous moles the O2 are created when 0.400 mol of KO2 reacts in this fashion?

(b) How countless grams that KO2 are necessary to form 7.50 g the O2?

(c) How countless grams the CO2 are used when 7.50 g that O2 room produced?

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3.63 several brands of antacids usage Al(OH)3 to react v stomach acid, which has primarily HCl:

Al(OH)3(s) + HCl(aq) → AlCl3(aq) + H2O(l)

(a) Balance this equation.

(b) calculation the variety of grams the HCl that deserve to react through 0.500 g that Al(OH)3.

(c) calculate the number of grams that AlCl3 and also the number of grams that H2O formed when 0.500 g of Al(OH)3 reacts.

(d) display that her calculations in components (b) and (c) are constant with the regulation of conservation of mass.

3.64 An steel ore sample consists of Fe2O3 along with other substances. Reaction the the ore through CO produces steel metal:

Fe2O3(s) + CO(g) → Fe(s) + CO2(g)

(a) Balance this equation.

(b) calculation the number of grams the CO that have the right to react v 0.350 kg that Fe2O3.

(c) calculation the number of grams that Fe and the variety of grams that CO2 developed when 0.350 kg that Fe2O3 reacts.

(d) show that her calculations in components (b) and (c) are regular with the law of preservation of mass.

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3.65 Aluminum sulfide reacts with water to form aluminum hydroxide and also hydrogen sulfide. (a) create the well balanced chemical equation because that this reaction. (b) How plenty of grams the aluminum hydroxide are derived from 14.2 g the aluminum sulfide?

3.66 Calcium hydride reacts through water to type calcium hydroxide and also hydrogen gas. (a) compose a balanced chemical equation for the reaction. (b) How plenty of grams that calcium hydride are needed to kind 4.500 g that hydrogen?

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3.67 Automotive air bags inflate as soon as sodium azide, NaN3, quickly decomposes to its ingredient elements:

2 NaN3(s) → 2 Na(s) + 3 N2(g)

(a) How many moles of N2 are produced by the decomposition of 1.50 mol of NaN3?

(b) How many grams the NaN3 are forced to form 10.0 g the nitrogen gas?

(c) How numerous grams of NaN3 are compelled to produce 10.0 ft3 the nitrogen gas, about the size of an automotive waiting bag, if the gas has a thickness of 1.25 g/L?

3.68 The complete combustion of octane, C8H18, the main component that gasoline, proceeds together follows:

2 C8H18(l) + 25 O2(g) → 16 CO2(g) + 18 H2O(g)

(a) How countless moles the O2 are needed to burn 1.50 mol that C8H18?

(b) How plenty of grams the O2 are necessary to burn 10.0 g of C8H18?

(c) Octane has a thickness of 0.692 g/mL at 20 °C. How numerous grams of O2 are compelled to burn 15.0 gal that C8H18 (the capacity of an typical fuel tank)?

(d) How numerous grams the CO2 are created when 15.0 gal that C8H18 room combusted?

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3.69 A item of aluminum foil 1.00 cm square and 0.550 mm thick is allowed to react v bromine to kind aluminum bromide. (a) How plenty of moles of aluminum were used? (The thickness of aluminum is 2.699 g/cm3.) (b) How numerous grams the aluminum bromide form, presume the aluminum reaction completely?

3.70 Detonation of nitroglycerin proceeds as follows:

4 C3H5N3O9(l) → 12 CO2(g) + 6 N2(g) + O2(g) + 10 H2O(g)

(a) If a sample include 2.00 mL the nitroglycerin (density = 1.592 g/mL) is detonated, how many complete moles of gas room produced? (b) If each mole that gas occupies 55 together under the conditions of the explosion, how countless liters that gas room produced? (c) How numerous grams that N2 are developed in the detonation?

LIMITING reactants (section 3.7)

3.71 (a) specify the state limiting reactant and also excess reactant. (b) Why space the amounts of commodities formed in a reaction identified only through the lot of the limiting reactant? (c) Why must you basic your selection of which link is the limiting reactant top top its variety of initial moles, not on its initial mass in grams?

3.72 (a) specify the terms theoretical yield, really yield, and percent yield. (b) Why is the actual yield in a reaction almost always much less than the theoretical yield? (c) can a reaction ever before have 110% actual yield?

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3.73 A manufacturer that bicycles has actually 4815 wheels, 2305 frames, and also 2255 handlebars. (a) How countless bicycles deserve to be produced using these parts? (b) How numerous parts that each kind are left over? (c) Which component limits the manufacturing of bicycles?

3.74 A bottling plant has actually 126,515 bottles through a capacity of 355 mL, 108,500 caps, and also 48,775 together of beverage. (a) How numerous bottles have the right to be filled and also capped? (b) just how much of each item is left over? (c) which component boundaries the production?

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3.75 salt hydroxide reacts with carbon dioxide together follows:

2 NaOH(s) + CO2(g) → Na2CO3(s) + H2O(l)

Which is the limiting reactant once 1.85 mol NaOH and 1.00 mol CO2 are permitted to react? How plenty of moles of Na2CO3 can be produced? How numerous moles that the overabundance reactant remain after the perfect of the reaction?

3.76 Aluminum hydroxide reacts with sulfuric acid as follows:

2 Al(OH)3(s) + 3 H2SO4(aq) → Al2(SO4)3(aq) + 6 H2O(l)

Which is the limiting reactant when 0.500 mol Al(OH)3 and also 0.500 mol H2SO4 are enabled to react? How numerous moles of Al2(SO4)3 can kind under this conditions? How many moles of the overabundance reactant remain after the perfect of the reaction?

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3.77 The fizz produced when an Alka-Seltzer® tablet is dissolved in water is as result of the reaction between sodium bicarbonate (NaHCO3) and also citric acid (H3C6H5O7):

3 NaHCO3(aq) + H3C6H5O7(aq) → 3 CO2(g) + 3 H2O(l) + Na3C6H5O7(aq)

In a certain experiment 1.00 g of sodium bicarbonate and also 1.00 g that citric acid are permitted to react. (a) which is the limiting reactant? (b) How countless grams that carbon dioxide form? (c) How countless grams that the excess reactant remain after the limiting reactant is completely consumed? 3.78 among the measures in the commercial process for converting ammonia come nitric acid is the counter of NH3 to NO:

4 NH3(g) + 5 O2(g) → 4 NO(g) + 6 H2O(g)

In a details experiment, 2.00 g the NH3 reacts through 2.50 g that O2(a) i beg your pardon is the limiting reactant? (b) How numerous grams the NO and of H2O form? (c) How plenty of grams the the overfill reactant continue to be after the limiting reactant is totally consumed? (d) display that her calculations in components (b) and (c) are constant with the legislation of conservation of mass.

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3.79 options of sodium carbonate and silver nitrate react to kind solid silver- carbonate and a systems of salt nitrate. A systems containing 3.50 g of salt carbonate is blended with one containing 5.00 g of silver nitrate. How plenty of grams of salt carbonate, silver- nitrate, silver carbonate, and sodium nitrate are present after the reaction is complete?

3.80 remedies of sulfuric acid and also lead(II) acetate react to type solid lead(II) sulfate and a systems of acetic acid. If 5.00 g the sulfuric acid and 5.00 g that lead(II) acetate space mixed, calculate the number of grams of sulfuric acid, lead(II) acetate, lead(II) sulfate, and also acetic acid existing in the mixture ~ the reaction is complete.

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3.81 once benzene (C6H6) reacts with bromine (Br2), bromoben-zene (C6H5Br) is obtained:

C6H6 + Br2 → C6H5Br + HBr

(a) once 30.0 g the benzene reacts with 65.0 g the bromine, what is the theoretical yield of bromobenzene? (b) If the actual productivity of bromobenzene is 42.3 g, what is the percent yield?

3.82 as soon as ethane (C2H6) reacts through chlorine (Cl2), the key product is C2H5Cl, but other commodities containing Cl, such together C2H4Cl2, are additionally obtained in small quantities. The development of this other products reduces the yield of C2H5Cl. (a) calculation the theoretical productivity of C2H5Cl when 125 g of C2H6 reacts v 255 g of Cl2, assuming the C2H6 and also Cl2 react just to form C2H2Cl and HCl. (b) calculation the percent productivity of C2H5Cl if the reaction produces 206 g the C2H5Cl.

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3.83 Hydrogen sulfide is an impurity in natural gas that should be removed. One common removal an approach is referred to as the Claus process, which depends on the reaction:

8 H2S(g) + 4 O2(g) → S8(l) + 8 H2O(g)

Under optimal conditions the Claus process gives 98% productivity of S8 indigenous H2S. If you began with 30.0 grams that H2S and 50.0 grams the O2, how plenty of grams that S8 would certainly be produced, suspect 98% yield?

3.84 as soon as hydrogen sulfide gas is bubbled into a solution of sodium hydroxide, the reaction develops sodium sulfide and water. How many grams of salt sulfide are developed if 1.25 g that hydrogen sulfide is bubbled right into a solution containing 2.00 g of salt hydroxide, assuming the the sodium sulfide is do in 92.0% yield?

3.85 write the balanced chemical equations because that (a) the complete combustion of acetic mountain (CH3COOH), the main active ingredient in vinegar; (b) the decomposition of solid calcium hydroxide into solid calcium(II) oxide (lime) and also water vapor; (c) the mix reaction in between nickel metal and also chlorine gas.

3.86 If 1.5 mol C2H5OH, 1.5 mol C3H8, and also 1.5 mol CH3CH2 COCH3 are completely combusted in oxygen, i m sorry produces the largest number of moles that H2O? i m sorry produces the least? Explain.

3.87 The efficiency of nitrogen fertilizers depends on both their capacity to supply nitrogen to plants and also the lot of nitrogen they deserve to deliver. Four common nitrogen-containing fertilizers space ammonia, ammonium nitrate, ammonium sulfate, and also urea <(NH2)2CO>. Rank this fertilizers in regards to the mass portion nitrogen lock contain.

3.88 (a) The molecular formula of acetylsalicylic acid (aspirin), among the most common pain relievers, is C9H8O4. How plenty of moles the C9H8O4 room in a 0.500-g tablet computer of aspirin? (b) How many molecules that C9H8O4 room in this tablet? (c) How numerous carbon atoms space in the tablet?

3.89 Very tiny crystals written of 1000 to 100,000 atoms, referred to as quantum dots, room being investigated for usage in electronic devices.

(a) A quantum period was do of solid silicon in the form of a sphere, with a diameter that 4 nm. Calculation the mass of the quantum dot, using the density of silicon (2.3 g/cm3).

(b) How countless silicon atoms space in the quantum dot?

(c) The thickness of germanium is 5.325 g/cm3. If friend made a 4-nm quantum period of germanium, how plenty of Ge atoms would it contain? i think the period is spherical.

3.90 (a) One molecule that the antibiotic penicillin G has a mass of 5.342 × 10−21 g. What is the molar fixed of penicillin G? (b) Hemoglobin, the oxygen-carrying protein in red blood cells, has 4 iron atoms every molecule and also contains 0.340% stole by mass. Calculation the molar massive of hemoglobin.

3.91 Serotonin is a compound that conducts nerve impulses in the brain. It includes 68.2 mass percent C, 6.86 fixed percent H, 15.9 mass percent N, and 9.08 mass percent O. Its molar massive is 176 g/mol. Recognize its molecule formula.

3.92 The koala dines specifically on eucalyptus leaves. Its digestive mechanism detoxifies the eucalyptus oil, a poison to various other animals. The chief constituent in eucalyptus oil is a substance dubbed eucalyptol, which contains 77.87% C, 11.76% H, and the remainder O. (a) What is the empirical formula because that this substance? (b) A massive spectrum of eucalyptol mirrors a top at about 154 amu. What is the molecule formula the the substance?

3.93 Vanillin, the dominant flavoring in vanilla, includes C, H, and O. Once 1.05 g the this problem is fully combusted, 2.43 g of CO2 and also 0.50 g of H2O space produced. What is the empirical formula that vanillin?

<3.94> an organic link was found to contain only C, H, and also Cl. As soon as a 1.50-g sample the the link was fully combusted in air, 3.52 g that CO2 to be formed. In a separate experiment the chlorine in a 1.00-g sample of the link was converted to 1.27 g of AgCl. Identify the empirical formula the the compound.

<3.95> A compound, KBrOx, where x is unknown, is analyzed and also found to contain 52.92% Br. What is the worth of x?

<3.96> An aspect X forms an iodide (Xl3) and a chloride (XCl3). The iodide is quantitatively convert to the chloride when it is boil in a present of chlorine:

2 XI3 + 3 Cl2 → 2 XCl3 + 3 I2

If 0.5000 g that Xl3 is treated, 0.2360 g of XCl3 is obtained. (a) calculation the atomic load of the element X. (b) identify the facet X.

3.97 A technique used by the U. S. Ecological Protection agency (EPA) because that determining the concentration the ozone in waiting is to happen the air sample through a “bubbler” containing salt iodide, which removes the ozone follow to the following equation:

O3(g) + 2 NaI(aq) + H2O(l) → O2(g) + I2(s) + 2 NaOH(aq)

(a) How numerous moles of salt iodide are required to eliminate 5.95 × 10−6 mol of O3? (b) How countless grams of sodium iodide are essential to eliminate 1.3 mg the O3?

3.98 A chemical plant uses electric energy to decompose aqueous options of NaCl to give Cl2, H2, and also NaOH:

2 NaCl(aq) + 2 H2O(l) → 2 NaOH(aq) + H2(g) + Cl2(g)

If the tree produces 1.5 × 106 kg (1500 metric tons) that Cl2 daily, estimate the amounts of H2 and NaOH produced.

3.99 The fat stored in a camel"s hump is a resource of both energy and also water. Calculate the mass of H2O developed by management of 1.0 kg that fat, presume the fat is composed entirely that tristearin (C57H110O6), a typical animal fat, and also assuming that throughout metabolism, tristearin reacts through O2 to form only CO2 and also H2O.

<3.100> once hydrocarbons are shed in a limited amount of air, both CO and also CO2 form. Once 0.450 g of a particular hydrocarbon was burned in air, 0.467 g the CO, 0.733 g that CO2, and also 0.450 g of H2O were formed. (a) What is the empirical formula of the compound? (b) How plenty of grams that O2 were supplied in the reaction? (c) How many grams would have been forced for finish combustion?

3.101 A mixture of N2(g) and H2(g) reaction in a closeup of the door container to form ammonia, NH3(g). The reaction ceases before either reactant has actually been completely consumed. In ~ this stage 3.0 mol N2, 3.0 mol H2, and 3.0 mol NH3 are present. How plenty of moles that N2 and H2 were current originally?

<3.102> A mixture include KClO3, K2CO3, KHCO3, and KCl was heated, developing CO2, O2, and also H2O gases follow to the following equations:

2 KClO3(s) → 2 KCl(s) + 3 O2(g)

2 KHCO3(s) → K2O(s) + H2O(g) + 2 CO2(g)

K2CO3(s) → K2O(s) + CO2(g)

The KCl does no react under the problems of the reaction. If 100.0 g the the mixture produces 1.80 g that H2O, 13.20 g that CO2, and also 4.00 g that O2, what was the ingredient of the initial mixture? (Assume complete decomposition that the mixture.)

3.103 once a mixture that 10.0 g that acetylene (C2H2); and 10.0 g of oxygen (O2) is ignited, the resultant combustion reaction produce CO2 and H2O. (a) write the balanced chemical equation because that this reaction. (b) i m sorry is the limiting reactant? (c) How countless grams of C2H2, O2, CO2, and also H2O are present after the reaction is complete?

3.104 Aspirin (C9H8O4) is developed from salicylic acid (C7H6O3) and also acetic anhydride (C4H6O3):

C7H6O3 + C4H6O3 → C9H8O4 + HC2H3O2

(a) just how much salicylic mountain is compelled to develop 1.5 × 102 kg that aspirin, suspect that every one of the salicylic mountain is converted to aspirin? (b) exactly how much salicylic acid would be compelled if only 80% the the salicylic mountain is convert to aspirin? (c) What is the theoretical yield of aspirin if 185 kg the salicylic acid is enabled to react with 125 kg of acetic anhydride? (d) If the case described in part (c) produce 182 kg the aspirin, what is the percent yield?

INTEGRATIVE EXERCISES

These practice require an abilities from earlier chapters as well as an abilities from the present chapter.

3.105 think about a sample of calcium carbonate in the form of a cube measuring 2.005 in. On each edge. If the sample has a thickness of 2.71 g/cm3, how countless oxygen atoms does the contain?

3.106 (a) friend are provided a cube of silver steel that procedures 1.000 cm on every edge. The thickness of silver is 10.5 g/cm3. How numerous atoms space in this cube? (b) since atoms space spherical, they can not occupy all of the an are of the cube. The silver atoms load in the heavy in together a method that 74% of the volume of the hard is actually filled with the silver atoms. Calculate the volume of a single silver atom. (c) utilizing the volume of a silver- atom and also the formula for the volume of a sphere, calculation the radius in angstroms the a silver atom.

3.107 (a) If an automobile travels 225 mi through a gas purpose of use of 20.5 mi/gal, how countless kilograms the CO2 room produced? Assume the the petrol is written of octane, C8H18(l), whose thickness is 0.69 g/mL. (b) Repeat the calculation because that a van that has a gas purpose of use of 5 mi/gal.

3.108 Section 2.9 presented the idea of structural isomerism, with 1-propanol and also 2-propanol as examples. Identify which of this properties would identify these two substances: (a) boiling point; (b) combustion evaluation results; (c) molecule weight; (d) density at a provided temperature and also pressure. Friend can examine on the properties of these 2 compounds in Wolfram Alpha (http://www.wolframalpha.com/) or the CRC Handbook that Chemistry and also Physics.

3.109 A specific coal consists of 2.5% sulfur by mass. Once this charcoal is melted at a power plant, the sulfur is converted right into sulfur dioxide gas, i beg your pardon is a pollutant. To minimize sulfur dioxide emissions, calcium oxide (lime) is used. The sulfur dioxide reacts v calcium oxide to type solid calcium sulfite. (a) Wr ns te the well balanced chemical equation for the reaction. (b) If the coal is shed in a power plant that offers 2000 loads of coal per day, what massive of calcium oxide is required day-to-day to eliminate the sulfur dioxide? (c) How many grams of calcium sulfite are created daily by this strength plant?

3.110 Copper is great electrical conductor widely used in making electrical circuits. In producing a published circuit board for the electronics industry, a layer of copper is laminated top top a plastic board. A circuit sample is then published on the board using a chemically resistant polymer. The plank is climate exposed to a chemistry bath that reacts v the exposed copper, leaving the wanted copper circuit, which has been safeguarded by the overlaying polymer. Finally, a solvent clears the polymer. One reaction provided to remove the exposed copper indigenous the circuit board is A plant needs to create 5000 circuit boards, each with a surface ar area measure 2.0 in. × 3.0 in. The boards space covered with a 0.65-mm great of copper. In succeeding processing, 85% that the copper is removed. Copper has a thickness of 8.96 g/cm3. Calculate the masses of Cu(NH3)4Cl2 and NH3 necessary to develop the circuit boards, assuming that the reaction used gives a 97% yield.

3.111 Hydrogen cyanide, HCN, is a gift gas. The lethal sheep is about 300 mg HCN every kilogram the air as soon as inhaled. (a) calculation the lot of HCN that gives the lethal sheep in a little laboratory room measure up 12 × 15 × 8.0 ft. The thickness of air at 26 °C is 0.00118 g/cm3. (b) If the HCN is developed by reaction that NaCN v an mountain such together H2SO4, what mass of NaCN gives the lethal sheep in the room?

2 NaCN(s) + H2SO4(aq) → Na2SO4(aq) + 2 HCN(g)

(c) HCN creates when synthetic fibers include Orlon® or Acrilan® burn. Acrilan® has actually an empirical formula the CH2CHCN, so HCN is 50.9% the the formula through mass. A rug measures 12 × 15 ft and contains 30 oz that Acrilan® fibers every square yard of carpet. If the rug burns, will a lethal sheep of HCN be generated in the room? Assume the the yield of HCN from the fibers is 20% and also that the carpet is 50% consumed.

See more: How Many Vertices Does A Triangular Prism Have, How Many Vertices Does A Triangular Prism

3.112 The source of oxygen the drives the internal combustion engine in an vehicle is air. Air is a mixture of gases, principally N2 (˜79%) and O2 (˜20%). In the cylinder the an car engine, nitrogen deserve to react v oxygen to produce nitric oxide gas, NO. Together NO is emitted from the tailpipe that the car, it have the right to react with an ext oxygen to create nitrogen dioxide gas. (a) Write balanced chemical equations for both reactions. (b) Both nitric oxide and nitrogen dioxide room pollutants that can lead to mountain rain and an international warming; collectively, lock are referred to as “NOx” gases. In 2007, the United claims emitted an estimated 22 million lots of nitrogen dioxide into the atmosphere. How many grams the nitrogen dioxide is this? (c) The manufacturing of NOx gases is an undesirable side reaction that the main engine combustion procedure that turns octane, C8H18, into CO2 and also water. If 85% the the oxygen in an engine is used to combust octane and the remainder provided to develop nitrogen dioxide, calculation how plenty of grams of nitrogen dioxide would certainly be produced during the combustion of 500 grams the octane.