Chapter 1



AP Chemistry Review Assignment

Brown and LeMay: Chemistry the Central Science, 11th edition

Chapter 1 “Introduction: Matter and Measurement” Assignments

Classification and Properties of Matter

Read: pp. 1-12; Exercises: p.31: #11,15,16

11. Classify each of the following as a pure substance or a mixture; if a mixture, indicate whether it is homogeneous

or heterogeneous:

a) rice pudding Heterogeneous mixture

b) seawater Homogeneous mixture unless there are undissolved particles such as sand, then heterogeneous

c) magnesium Element

d) gasoline Homogeneous mixture

15. A solid white substance A is heated strongly in the absence of air. It decomposes to form a new white substance B and a gas C. The gas has exactly the same properties as the product obtained when carbon is burned in an excess of oxygen. Based on these observations, can we determine whether solids A and B and the gas C are elements or compounds? .A – compound B – cannot be determined, C - compound

16. In the process of attempting to characterize a substance, a chemist makes the following observations:

The substance is a silvery white, lustrous metal. It melts at 649oC and boils at 1105oC. Its density at 20oC is 1.738

g/cm3. The substance burns in air, producing an intense white light. It reacts with chlorine to give a brittle white

solid. The substance be pounded into thin sheets or drawn into wires. It is a good conductor of electricity.

Red – Physical, Green - Chemical

Units of Measurement

Read: pp. 13-19; Exercises: p. 32: #23, 24, 27

23. What decimal power do the following abbreviations represent?

a) D 1 x 10-1

b) c 1 x 10-2

c) f 1 x 10-15

d) μ 1 x 10-6

d) M 1 x 106

e) K 1 x 103

f) n 1 x 10-9

g) m 1 x 10-3

h) p 1 x 10-12

24. Use the appropriate metric prefixes to write the following measurements without use of exponents:

a) 6.35 x 10-2 L 63.5 mL

b) 6.5 x 10-4 s 6.5 μs

c) 9.5 x 10-4 m 0.95 mm

d) 4.23 x 10-9 m3 4.23 mm3

e) 12.5 x 10-8 kg 0.125 mg (125 μg)

f) 3.5 x 10-10 g 0.35 ng

g) 6.54 x 109 fs 6.54 μs

27. a) A sample of carbon tetrachloride, a liquid once used in dry cleaning, has a mass of 39.73 g and

a volume of 25.0 mL at 25oC. What is its density at this temperature? Will carbon tetrachloride

float on water? 1.59 g/mL, carbon tetrachloride will sink in water

b) The density of platinum is 21.45 g/cm3 at 20oC. Calculate the mass of 75.00 cm3 of platinum at this temperature. 1.609 kg

c) The density of magnesium is 1.738 g/cm3 at 20oC. What is the volume of 87.50 g of this metal at this temperature? 50.35 mL

Uncertainty in Measurement

Read: pp. 20-24; Exercises: pp. 32,33: #33, 35, 39

33. Indicate which of the following are exact numbers: c, d, and f

a) the mass of a paper clip

b) the surface area of a dime

c) the number of inches in a mile

d) the number of ounces in a pound

e) the number of microseconds in a week

f) the number of pages in your textbook

35. What is the number of significant figures in each of the following measured quantities:

a) 358 kg 3

b) 0.0054 s 2

c) 6.3050 cm 5

d) 0.0105 L 3

e) 7.0500 x 10-3 m3 5

39. Carry out the following operations, and express the answers with the appropriate numbers of significant figures:

a) 12.0550 + 9.05 = 21.11

b) 257.2 - 19.789 = 237.4

c) (6.21 x 103)(0.1050) = 652

d) 0.0577/75.3 = 7.66 x 10-2

Dimensional Analysis

Read: pp. 24-29; Exercises: p. 33: #43, 48, 53

43. Perform the following conversions:

a) 0.076 L to mL 76 mL

b) 5.0 x 10-8 m to nm 50. nm

c) 6.88 x 105 ns to s 6.88 x 10-4 s

d) 0.50 lb to g 2.3 x 102 g

e) 5.850 gal/hr to L/s 1.55 g/L

48. a) If an electric car is capable of going 225 km on a single charge, how many charges will it need to travel from Boston, Massachusetts, to Miami, Florida, a distance of 1486 mi, assuming that the trip begins with a full charge? 10.6 charges

b) If a migrating loon flies at an average speed of 14 m/s, what is its average speed in mi/hr? 31 mi/hr

c) What is the engine piston displacement in liters of an engine whose displacement is listed as 450 in3? 7.37 L

d) In March 1989, the Exxon Valdez ran aground and spilled 240,000 barrels of crude petroleum off the coast of Alaska. One barrel of petroleum is equal to 42 gal. How many liters of petroleum were spilled? 3.8 x 10-7 L

53. The Morgan silver dollar has a mass of 26.73 g. By law, it was required to contain 90% silver, with the remainder being copper.

a) When the coin was minted in the late 1800s, silver was worth $1.18 per troy ounce (31.1 g).

At this price, what is the value of the silver in the silver dollar? $0.91

b) Today, silver sells for $13.25 per troy ounce.

How many Morgan silver dollars are required to obtain $25.00 worth of pure silver? 2.4 coins, so 3 coins needed.

Chapter 2 “Atoms, Molecules and Ions” Assignments

The Atomic Theory and The Discovery of Atomic Structure

Read: pp. 37-42; Exercises: pp. 69-71: #1, 15, 16,

1. A negatively charged particle is caused to move between two electrically charged plates, as illustrated

below

[pic]

a) Why does the path of the charged particle bend? The path of the charged particle bends because it is repelled by the negatively charged plate and attracted to the positively charged plate.

b) As the charge on the plates is increased, would you expect the bending to increase, decrease, or stay the

same? Like charges repel and opposite charges attract, so the sign of the electrical charge on the particle is negative.

c) As the mass of the particle is increased while the speed of the particles remains the same, would you expect the bending to increase, decrease, or stay the same? The greater the magnitude of the charges, the greater the electrostatic repulsion or attraction. As the charge on the plates is increased, the bending will increase.

d) An unknown particle is sent through the apparatus. Its path is deflected in the opposite direction from the negatively-charged particle, and it is deflected by a smaller magnitude. What can you conclude about this unknown particle? As the mass of the particle increase and speed stays the same, linear momentum of the particle increases and bending decreases.

15.

a) As shown in Figure 2.5 above, the positively-charged plate is above the negatively-charged plate.

What do you think would be the effect on the rate of oil drops descending if the charges on the plates

were reversed (negative above positive)? If the positive plate were lower than the negative plate the oil drops coated w/ negatively charged electrons would be attracted to the positively charged plate and would descend more quickly.

b) In his original series of experiments, Millikan measured the charge on 58 separate oil drops. Why do you suppose he chose so many drops before reaching his final conclusions? The more times a measurement is repeated, the better the chance of detecting and compensating for experimental errors.

16. Millikan determined the charge on the electron by studying the static charges on oil drops falling in an electric

field. A student carried out this experiment using several oil drops for her measurements and calculated the

charges on the drops. She obtained the following data:

|Droplet |Calculated Charge (C) |

|A |1.60 x 10-19 |

|B |3.15 x 10-19 |

|C |4.81 x 10-19 |

|D |6.31 x 10-19 |

a) What is the significance of the fact that the droplets carried different charges? The droplets carry different total charges because there may be 1,2,3 or more electrons on the droplet.

b) What conclusion can the student draw from these data regarding the charge of the electron? The electronic charge is likely to be the lowest common factor in all the observed charges.

c) What value (and to how many significant figures) should she report for the electronic charge? The average of the apparent electrical charges is 1.59 x 10-19 C

The Modern View of Atomic Structure and Atomic Weights

Read: pp. 43-48; Exercises: pp. 71,72: # 17, 20, 25, 29, 31

17. The radius of an atom of krypton (Kr) is about 1.9 A.

a) Express this distance in nanometers (nm) and in picometers (pm). 1.9 x 102 pm

b) How many krypton atoms would have to be lined up to span 1.0 mm? 2.6 x 106Kr atoms

c) If the atom is assumed to be a sphere, what is the volume in cm3 of a single Kr atom? 2.9 x 10-23 cm3

20. Determine whether each of the following statements is true or false; if false, correct the statement to make it true:

a) The nucleus has most of the mass and comprises very little of the volume of an atom;

b) Every atom of a given element has the same number of protons; True

c) The number of electrons in an atom equals the number of protons in the atom;

d) The protons in the nucleus of the helium atom are held together by a force called the strong nuclear force. True

25. Fill in the gaps in the following table assuming each column represents a neutral atom:

|Symbol |52Cr |55Mn |112Cd |222Rn |207Pb |

|Protons |24 |25 |48 |86 |82 |

|Neutrons |28 |30 |64 |136 |125 |

|Electrons |24 |25 |48 |86 |82 |

|Mass number |52 |55 |112 |222 |207 |

29. a) What isotope is used as the standard in establishing the atomic mass scale? Carbon - 12

b) The atomic weight of boron is reported as 10.81, yet no atom of boron has the mass of

10.81 amu. Explain. Atomic weights are really average atomic masses, the sum of the mass of each naturally occurring isotope of an element times its fractional abundance. Each B atom will have the mass of one of the naturally occurring isotopes, while the atomic weight is an average value.

31. Only two isotopes of copper occur naturally, 63Cu (atomic mass = 62.9296 amu; abundance 69.17%) and 65Cu

(atomic mass = 64.9278; abundance 30.83%). Calculate the atomic weight (average atomic mass) of copper.

63.55 amu

The Periodic Table and Molecules and Molecular Compounds

Read: pp. 49-54; Exercises: pp. 72,73: #38, 40, 43, 44, 51

38. Locate each of the following elements in the periodic table; indicate whether it is a metal, metalloid, or

non-metal; and give the name of the element:

a) Ca calcium (metal)

b) Ti Titanium (metal)

c) Ga gallium (metal)

d) Th thorium (metal)

e) Pt platinum (metal)

f) Se selenium (nonmetal)

g) Kr krypton (nonmetal)

40. The elements of group 4A show an interesting change in properties with increasing period.

Give the name and chemical symbol of each element in the group, and label it as a nonmetal,

metalloid, or metal. C, carbon, nonmetal; Si, silicon, metalloid; Ge, germanium, metalloid; Sn, tin, metal; Pb, lead, metal

43. Write the empirical formula corresponding to each of the following molecular formulas:

a) Al2Br6 AlBr3

b) C8H10 C4H5

c) C4H8O2 C2H4O2

d) P4O10 P2O5

e) C6H4Cl2 C3H2Cl

f) B3N3H6 BNH2

44. Determine the molecular and empirical formulas of the following:

a) the organic solvent benzene, which has six carbon atoms and six hydrogen atoms; C6H6, CH

b) the compound silicon tetrachloride, which has a silicon atom and four chlorine atoms and is used in the

manufacture of computer chips; SiCl4 for both

c) the reactive substance diborane, which has two boron atoms and six hydrogen atoms; B2H6, BH3

b) the sugar called glucose, which has six carbon atoms, twelve hydrogen atoms, and six oxygen atoms. C6H12O6, CH2O

51. Each of the following elements is capable of forming an ion in chemical reactions.

By referring to the periodic table, predict the charge of the most stable ion of each:

a) Mg2+

b) Al3+

c) K1+

d) Se2+

e) F1-

Ions and Ionic Compounds

53. Using the periodic table to guide you, predict the formula and name of the compound formed by the

following elements:

a) Ga and F GaF3, gallium (III) fluoride

b) Li and H LiF, lithium hydride

c) Al and I AlI3, Aluminum iodide

d) K and S K2S, potassium sulfide

55. Predict the empirical formula for the ionic compound forms by

a) Ca2+ and Br- CaBr2

b) K+ and CO32- K2CO3

c) Al3+ and C2H3O2- Al(C2H3O2)3

d) NH4+ and SO42- (NH4)2SO4

e) Mg2+ and PO43- Mg3(PO4)2

59. Predict whether each of the following compounds is molecular or ionic:

a. B2H6

b. CH3OH

c. LiNO3

d. Sc2O3

e. CsBr

f. NOCl

g. NF3

h. Ag2SO4

Naming Inorganic Compounds and Some Simple Organic Compounds

63. Give the names and charges of the cation and anion in each of the following compounds:

a) CaO calcium, 2+; oxide 2-

b) Na2SO4 sodium, 1+; sulfate, 2-

c) KClO4 potassium 1+; Chloride 1-

d) Fe(NO3)2 iron, 2+; nitrate 1-

e) Cr(OH)3 chromium 3+; hydroxide 1-

68. Give the chemical formulas for each of the following ionic compounds:

a) sodium phosphate Na3PO4

b) zinc nitrate Zn(NO3)2

c) barium bromate Ba(BrO3)2

d) iron(II) perchlorate Fe(ClO4)2

e) cobalt(II) hydrogen carbonate Co(HCO3)2

f) chromium(III) acetate Cr(C2H3O2)3

g) potassium dichromate K2Cr2O7

69. Give the name or chemical formula, as appropriate, for each of the following acids:

a) HBrO3 bromic acid

b) HBr hydrobromic acid

c) H3PO4 phosphoric acid

d) hypochlorous acid HClO

e) iodic acid HIO3

f) sulfurous acid H2SO3

73. Write the chemical formula for each substance mentioned in the following word descriptions.

a) Zinc carbonate can be heated for form zinc oxide and carbon dioxide. Zn(CO3)2, ZnO, CO2

b) On treatment with hydrofluoric acid, silicon dioxide forms silicon tetrafluoride and water.

HF, SiO2, SiF4, H2O

c) Sulfur dioxide reacts with water to form sulfurous acid. SO2, H2O, H2SO3

d) The substance phosphorus trihydride, commonly called phosphine, is a toxic gas. PH3

e) Perchloric acid reacts with cadmium to form cadmium (II) perchlorate. HClOr, Cd, Cd(ClO4)2

f) Vanadium (III) bromide is a colored solid. VBr3

74. Assume that you encounter the following phrases in your reading.

What is the chemical formula for each substance mentioned?

a) Sodium hydrogen carbonate is used as a deodorant. NaHCO3

b) Calcium hypochlorite is used in some bleaching solutions. Ca(ClO)2

c) Hydrogen cyanide is a very poisonous gas. HCN

d) Magnesium hydroxide is used as a cathartic. Mg(OH)2

e) Tin(II) fluoride has been used as a fluoride additive in toothpastes. SnF2

f) When cadmium sulfide is treated with sulfuric acid, fumes of hydrogen sulfide are given off. CdS, H2SO4. H2S

Chapter 3 “Stoichiometry: Calculations with Chemical Formulas and Equations” Assignments

Chemical Equations

11. Balance the following equations:

a) 2CO(g) + O2(g) ⋄ 2CO2(g)

b) N2O5(g) + H2O(l) ⋄ 2HNO3(aq)

c) CH4(g) + 4Cl2(g) ⋄ CCl4(l) + 4HCl(g)

d) Al4C3(s) + 12H2O(l) ⋄ 4 Al(OH)3(s) + 3CH4(g)

e) 2C5H10O2(l) + 13O2(g) ⋄ 10CO2(g) + 10H2O(g)

f) 2Fe(OH)3(s) + 3H2SO4(aq) ⋄ Fe2(SO4)3(aq) + 6 H2O(l)

g) Mg3N2(s) + 4H2SO4(aq) ⋄ 3 MgSO4(aq) + (NH4)2SO4(aq)

13. Write balanced chemical equations to correspond to each of the following descriptions:

a) Solid calcium carbide, CaC2, reacts with water to form an aqueous solution of calcium hydroxide and acetylene gas, C2H2. CaC2 + 2H2 O ( Ca(OH)2 + C2H2

b) When solid potassium chlorate is heated, it decomposes to form solid potassium chloride and oxygen gas.

2KClO3(s) ( 2KCl (s) + 3O2

c) Solid zinc metal reacts with sulfuric acid to form hydrogen gas and an aqueous solution of zinc sulfate.

Zn(s) + H2SO4(aq) ( H2 + ZnSO4(aq)

d) When liquid phosphorus trichloride is added to water, it reacts to form aqueous phosphorous acid, H3PO3(aq), and aqueous hydrochloric acid. PCl3 (l) + 3H2O(l) ( H3PO3(aq) + 3HCl(aq)

e) When hydrogen sulfide gas is passed over solid hot iron(III) hydroxide, the resultant reaction produces solid iron(III) sulfide and gaseous water. 3H2S(g) + 2Fe(OH)3(s) ( Fe2S3 (s) + 6H2O(g)

Some Simple Patterns of Chemical Reactivity

15. a) When the metallic element sodium combines with the nonmetallic element bromine, Br2(l), how can you

determine the chemical formula of the product? How do you know whether the product is a solid, liquid, or gas

at room temperature? Write the balanced chemical equation for the reaction. 2Na(s) + Br2(l) ( 2NaBr

b) When a hydrocarbon burns in air, what reactant besides the hydrocarbon is involved in the reaction? Oxygen gas What products are formed? Carbon dioxide and water Write a balanced chemical equation for the combustion of benzene, C6H6(l), in air. 2C6H6(l) + 15 O2(g) ( 12CO2(g) + 6 H2O(l)

17. Write a balanced chemical equation for the reaction that occurs when

a) solid magnesium reacts with chlorine gas; Mg(s) + Cl2(g) ( MgCl2(s)

b) nickel(III) hydroxide decomposes into nickel(II) oxide and water when heated;

2Ni(OH)3 ( 2NiO + 3H2O

c) the hydrocarbon styrene, C8H8(l), is combusted in air; C8H8 + 10O2 ( 8CO2 + 4H2O

d) the gasoline additive MTBE (methyl tertiary-butyl ether), C5H12O(l), burns in air.

2C5H12O(l), + 15 O2 ( 10CO2 + 12H2O

19. Balance the following equations, and indicate whether they are combination, decomposition, or combustion

reactions:

a) 2Al(s) + 3Cl2(g) ⋄ 2AlCl3(s) Combination

b) C2H4(g) + 3O2(g) ⋄ 2CO2(g) + 2H2O(g) Combustion

c) 2Li(s) + N2(g) ⋄ 2Li3N(s) Combination

d) PbCO3(s) ⋄ PbO(s) + CO2(g) Decomposition

e) C7H8O2(l) + 8O2(g) ⋄ 7CO2(g) + 4H2O(g) Combustion

Formula Weights

21. Determine the formula weights (molar masses) of each of the following compounds:

a) nitric acid, HNO3, 63.0 g/mol

b) potassium permanganate, KMnO4, 158.0 g/mol

c) calcium phosphate, Ca3(PO4)2, 270.2 g/mol

d) quartz, SiO2, 60.1 g/mol

e) gallium sulfide Ga2S3, 235.7 g.mol

f) chromium (III) sulfate Cr2 (SO4)3, 296.2 g/mol

g) phosphorus trichloride PCl3, 106.4 g/mol

24. Calculate the percentage by mass of the indicated element in the following compounds:

a) carbon in acetylene, C2H2, a gas used in welding 92.3 % C

b) hydrogen in ascorbic acid, HC6H7O6, also known as vitamin C 4.5 % H

c) hydrogen in ammonium sulfate, (NH4)2SO4, a substance used as a nitrogen fertilizer 6.1 % H

d) platinum in PtCl2(NH3)2, a chemotherapy agent called cisplatin 65.0 % Pt

e) oxygen in the female sex hormone estradiol, C18H24O2 11.8 % O

f) carbon in capsaicin, C18H27NO3, the compound that gives the hot taste to chili peppers 70.8 % C

The Mole

29. Without doing any detailed calculations (but using a periodic table to give atomic weights), rank the following

samples in order of increasing number of atoms: 0.50 mol H2O; 23 g Na; 6.0 x 1023 N2 molecules.

Na, H2O , N2

33. Calculate the following quantities:

a) mass, in grams, of 0.105 moles sucrose (C12H22O11) 35.9 g sucrose

b) moles of Zn(NO3)2 in 143.50 g of this substance 0.7576 mol Zinc Nitrate

c) number of molecules in 1.0 x 10-6 mol CH3CH2OH 6.0 x 1017 Ethanol molecules

d) number of N atoms in 4.88 x 10-3 mol Al(NO3)3

37. The molecular formula of allicin, the compound responsible for the characteristic smell of garlic, is C6H10OS2.

a) What is the molar mass of allicin? C6H10OS2

b) How many moles of allicin are present in 5.00 mg of this substance? 3.08 x 10-5 moles

c) How many molecules of allicin are in 5.00 mg of this substance? 1.86 x 1019 molecules

d) How many S atoms are present in 5.00 mg of allicin? 3.71 x 1019 S atoms

Empirical Formulas from Analysis

43. Give the empirical formula of each of the following compounds if a sample contains

a) 0.0130 mol C, 0.0390 mol H, and 0.0065 mol O C2H6O

b) 11.66 g iron and 5.01 g oxygen Fe2O3

c) 40.0% C, 6.7% H, and 53.3% O by mass CH2O

45. Determine the empirical formulas of the compounds with the following compositions by mass:

a) 10.4% C, 27.8% S, and 61.7% Cl CSCl2

b) 21.7% C, 9.6% O, and 68.7% F C3OF6

c) 32,79% Na, 13.02% Al, and 54.19% F Na3AlF6

47. What is the molecular formula of each of the following compounds?

a) empirical formula CH2, molar mass = 84 g/mol C6H12

b) empirical formula NH2Cl, molar mass = 51.5 g/mol Same!

49. Determine the empirical and molecular formulas of each of the following substances:

a) Styrene, a compound substance used to make Styrofoam cups and insulation, 92.3% C and 7.7% H by mass and

has a molar mass of 104 g/mol; CH, C8H8

b) caffeine, a stimulant found in coffee, contains 49.5% C, 5.15% H, 28.09% N, and 16.5% O by mass and has a

molar mass of 195 g/mol; C4H5N2O; C8H10N4O2

c) monosodium glutamate (MSG), a flavor enhancer in certain foods that contains 35.51% C, 4.77% H,

37.85% O, 8.29% N, and 13.60% Na, and has a molar mass of 169 g/mol. NaC5H8O4N for both

Quantitative Information from Balanced Equations

57. Hydrofluoric acid, HF(aq), cannot be stored in glass bottles because compounds called silicates in the glass are

attacked by the HF(aq). Sodium silicate (Na2SiO3), for example, reacts as follows:

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

a) How many moles of HF are needed to react with 0.300 mol of Na2SiO3? 2.40 mol HF

b) How many grams of NaF form when 0.500 mol of HF reacts with excess Na2SiO3? 5.25 g NaF

c) How many grams of Na2SiO3 can react with 0.800 g of HF? 0.610 g Na2SiO3

58. The fermentation of glucose (C6H12O6) produces ethyl alcohol (C2H5OH) and CO2:

C6H12O6 (aq) ⋄ 2 C2H5OH (aq) + 2 CO2 (aq)

a) How many moles of CO2 are produced when 0.400 mol of C6H12O6 reacts in this fashion? 0.800 mol CO2

b) How many grams of C6H12O6 are needed to form 7.50 g of C2H5OH? 14.7 g C6H12O6

c) How many grams of CO2 form when 7.50 g of C2H5OH are produced 7.16 g CO2

61. Aluminum sulfide reacts with water to form aluminum hydroxide and hydrogen sulfide.

a) Write the balanced chemical equation for this reaction. Al2S3(s) + 6H2O(l) ( 2Al(OH)3(s) + 3H2S(g)

b) How many grams of aluminum hydroxide are obtained from 10.5 g of aluminum sulfide? 14.7 g Al(OH)3

64. The complete combustion of octane, C8H18, a component of gasoline, proceeds as follows:

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

a) How many moles of O2 are needed to burn 1.25 mol of C8H18?15.6 moles O2

b) How many grams of O2 are needed to burn 10.0 g of C8H18? 35.0 g O2

c) Octane has a density of 0.692 g/mL at 20oC. How many grams of O2 are required to burn 1.00 gal of C8H18? 9.18 x 103g O2

Limiting Reactants: Theoretical Yields

70. A bottling plant as 121,515 bottles with a capacity of 355 mL, 122,500 caps, and 40,875 L of beverage. (a) How many bottles can be filled and capped? 1.15 x 105 bottles can be filled and capped (b) How much of each item is left over? 7 x 103 caps remain and 6 x 103 bottles remain (c) Which component limits the production? The volume of the beverage limits production

72. Aluminum hydroxide reacts with sulfuric acid as follows:

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

Which reagent is the limiting reactant when 0.500 mol 2Al(OH)3 0.500 mol H2SO4 are allowed to react? H2SO4 How many moles of Al2(SO4)3 can form under these conditions? 0.167 mol Al2(SO4)3 can form How many moles of the excess reactant remain after the completion of the reaction? 0.167 mol Al(OH)3 remain

74. One of the steps in the commercial process for converting ammonia to nitric acid is the conversion of NH3 to NO:

4 NH3 (g) + 5 O2 (g) --> 4 NO (g) + 6 H2O (g)

In a certain experiment, 1.50 g of NH3 reacts with 2.75 g of O2. (a) Which is the limiting reactant? O2 (b) How many grams of NO and of H2O form? 1.86 g water formed (c) How many grams of the excess reactant remain after the limiting reactant is completely consumed? 0.329 g NH3 re,aom (d) Show that your calculations in parts (b) and (c) are consistent with the law of conservation of mass. Mass products = 2.06 g NO + 1.86 g H2O + 0.329 g NH3 remaining = 4.25 g products

Mass reactants = 1.50 g NH3 + 2.75 g O2 = 4.25 g. reactants

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