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All Textbook Solutions for Introductory Chemistry: A Foundation

Estimate the length of time it would take you to count to Ayogadro’s number. Provide mathematical support.Suppose Avogadro’s number was 1000 instead of 6.0221023 . How, if at all, would this affect the relative masses on the periodic table? How, if at all, would this affect the absolute masses of the elements?Estimate the number of atoms in your body and provide mathematical support. Because it is an estimate, it need not be exact, although you should choose your number wisely.Consider separate equal mass samples of magnesium, zinc, and silver. Rank them from greatest to least number of atoms and support your answer.You have a 20.0-g sample of silver metal. You are given 10.0 g of another metal and told that this sample contains twice the number of atoms as the sample of silver metal. Identify this metal.How would you find the number of “ink molecules” it takes to write your name on a piece of paper with your pen? Explain what you would need to do, and provide a sample calculation.True or false? The atom with the largest subscript in a formula is the atom with the largest percent by mass in the compound. If true, explain why with an example. If false, explain why and provide a counter example. In either case, provide mathematical support.Which of the following compounds have the same empirical formulas? mg src=Images/HTML_99425-8-22ALQ_image001.jpg alt="" align="top"/>The percent by mass of nitrogen is 46.7% for a species containing only nitrogen and oxygen. Which of the following could he this species? mg src=Images/HTML_99425-8-23ALQ_image001.jpg alt="" align="top"/>24ALQ Give the empirical formula for each of the compounds represented below. mg src=Images/HTML_99425-8-25ALQ_image001.jpg alt="" align="top"/>erchants usually sell small nuts, washers, and bolts by weight (like jelly beans!) rather than by individually counting the items. Suppose a particular type of washer weighs 0.110 g on the average. What would 100 such washers weigh? How many washers would there be in 100. g of washers?he “Chemistry in Focus” segment Plastic That Talks and Listens! discusses polyvinylidene difluoride (PVDF). What is the empirical formula of PVDF? Note: An empirical formula is the simplest whole-number ratio of atoms in a compound. This is discussed more fully in Sections 8.7 and 8.8 of your text.efine the amu. What is one amu equivalent to in grains?hat do we mean by the average atomic mass of an element? What is “averaged” to arrive at this number?sing the average atomic masses for each of the following elements (see the table inside the cover of this book), calculate the mass (in amu) of each of the following samples. l type='a'> 125 carbon atoms 5 million potassium atoms 1.041022 lithium atoms 1 atom of magnesium 3.0111023 iodine atoms sing the average atomic masses for each of the following elements (see the table inside the front cover of this book), calculate the number of atoms present in each of the following samples. l type='a'> 40.08 amu of calcium 919.5 amu of tungsten 549.4 amu of manganese 6345 amu of iodine 2072 amu of lead 7QAP he atomic mass of copper is 63.55 amu. What would be the mass of 75 copper atoms? How many copper atoms are contained in a sample of copper that has a mass of 6100.8 arnu?here are _________ iron atoms present in 55.85 g of iron.There are 6.0221023 zinc atoms present in g of zinc.Suppose you have a sample of sodium weighing 11.50 g. How many atoms of sodium are present in the sample? What mass of potassium would you need to have the same number of potassium atoms as there are sodium atoms in the sample of sodium?Consider a sample of silver weighing 30OE0 g. How many at oms of silver are present in the sample? What mass of copper would you need for the copper sample to contain the same number of atoms as the silver sample?What mass of hydrogen contains the same number of atoms as 7.00 g of nitrogen?What mass of cobalt contains the same number of atoms as 57.0 g of fluorine?If an average sodium atom has a mass of 3.821023 g. what is the mass of a magnesium atom in grams?Ifan average fluorine atom has a mass of 3.161023 g, what is the average mass of a chlorine atom in grams?Which has the smaller mass, 1 mole of He atoms or 4 moles of H atoms?Which weighs less, 0.25 mole of xenon atoms or 2.0 moles of carbon atoms?Use the average atomic masses given inside the front cover of this book to calculate the number of moles of the element present in each of the following samples. l type='a'> 4.95 g of neon 72.5 gof nickel 115 mgofsilver 6.22 g of uranium ( is a standard abbreviation meaning “micro”) 135 gof iodine Use the average atomic masses given inside the front cover of this hook to calculate the number of moles of the element present in each of the following samples. l type='a'> 49.2 g of sulfur 7.44104 kg of lead 3.27 mg of chlorine 4.01 g of lithium l00.Ogofcopper 82.6 mg of strontium Use the average atomic masses given inside the front cover of this book to calculate the mass in grains of each of the following samples. l type='a'> 0.251 mole of lithium 1.51 moles of aluminum 8.75102 moles of lead 125 moles of chromium 4.25103 moles of iron 0.000105 mole of magnesium Use the average atomic masses given inside the front cover ofthis book to calculate the mass in grams of each of the following samples. l type='a'> 0.00552 mole of calcium 6.25 mmol of boron (1mmol=11000mole) i>135 moles of aluminum 1.34107 moles of barium 2.79 moles of phosphorus 0.0000997 mole of arsenic Using the average atomic masses given inside the front cover of this book, calculate the number of atoms present in each of the following samples. l type='a'> 1.50 g of silver, Ag 0.0015 moIe of copper, Cu 0.0015 g of copper, Cu 2.00 kg of magnesium, Mg 2.34 oz of calcium, Ca 2.34 g of calcium, Ca 2.34 moles of calcium, Ca Using the average atomic masses given inside the front cover of this book, calculate the indicated quantities. l type='a'> the mass in grams of 125 iron atoms the mass in amu of 125 iron atoms the number of moles of iron atoms in 125 g of iron the mass in grams of 125 moles of iron the number of iron atoms in 125 g of iron the number of iron atoms in 125 moles of iron The _________ of a substance is the mass (in grams) of 1 mole of the substance.26QAP Give the name and calculate the molar mass for each of the following substances. l type="a"> H3PO4 i>Fe2O3 i>NaClO4 i>PbCl2 i>HBr i>Al(OH)3 Give the name and calculate the molar mass for each of the following substances. l type="a"> KHCO3 i>Hg2Cl2 i>H2O2 i>BeCl2 i>Al2( SO4)3 i>KClO3 Write the formula and calculate the molar mass for each of the following substances. l type='a'> barium chloride sulfur dioxide aluminum nitrate calcium acetate iron(II) chloride Write the formula and calculate the molar mass for each of the following substances. l type='a'> carbon dioxide aluminum phosphate iron(III) carbonate lead(II) nitrate strontium chloride Calculate the number of moles of the indicated substance present in each of the following samples. l type='a'> 21.4 mg of nitrogen dioxide 1.56 g of copper(II) nitrate 2.47 g of carbon disulfide 5.04 g of aluminum sulfate 2.99 g of lead(II) chloride 62.4 g of calcium carbonate 32QAP 33QAP Calculate the number of moles of the indicated substance present in each of the following samples. l type='a'> 1.95103 g of lithium carbonate 4.23 kg of calcium chloride 1.23 mg of strontium chloride 4.75 g of calcium sulfate 96.2 mg of nitrogen(IV) oxide 12.7 g of mercury(I) chloride Calculate the mass in grams of each of the following samples. l type='a'> 1.25 moles of aluminum chloride 3.35 moles of sodium hydrogen carbonate 4.25 millimoles of hydrogen bromide C6H12O6(1mmol=11000mole) i>1.31103 moles of uranium 0.00104 mole of carbon dioxide 1.49102 moles of iron Calculate the mass in grams of each of the following samples. l type="a"> 6.14104 moles of sulfur trioxide 3.11105 moles of lead(IV) oxide 0.495 mole of chloroform, CHCl3 i>2.45108 moles of trichloroethane, C2H3Cl3 i>0.167 mole of lithium hydroxide 5.26 moles of copper(l) chloride Calculate the mass in grams of each of the following samples. l type="a"> 0.251 mole of ethyl alcohol, C2H6O i>1.26 moles of carbon dioxide 9.31104 moles of gold(III) chloride 7.74 moles of sodium nitrate 0.000357 mole of iron Calculate the mass in grams of each of the following samples. l type="a"> 0.994 mole of benzene, C6H6 i>4.21 moles of calcium hydride 1.79104 moles of hydrogen peroxide, H2O2 i>1.22 rnmol of glucose, C6H12O6(1mmol=11000mole) i>10.6 moles of tin 0.000301 moIe of strontium fluoride Calculate the number of molecules present in each of the following samples. l type="a"> 4.75 mmol of phosphine, PH3 i>4.75 g of phosphine, PH3 i>1.25102 g of lead(II) acetate, Pb( CH3 CO2)2 i>1.25 X 10 2 moles of lead(II) acetate, Pb( CH3 CO2)2 i>a sample of benzene, C6H6 , which contains a total of 5.40 moles of carbon Calculate the number of molecules present in each of the following samples. oles of sulfur dioxide, SO2 of sulfur dioxide, SO2 :math>4.46105 g of ammonia, NH3 :math>4.46105 moles of ammonia, NH3 g of ethane, C2H6 Calculate the number of moles of carbon atoms present in eachof the following samples. l type="a"> 1.271 g of ethanol, C2H5OH i>3.982 g of 1 ,4-dichlorobenzene, C6H4Cl2 i>0.4438 g of carbon suboxide, C3O2 i>2.9 10 g of methylene chloride, CH2Cl2 Calculate the number of moles of sulfur atoms present in each of the following samples. l type='a'> 2.01 g of sodium sulfate 2.01 g of sodium sulfite 2.01 g of sodium sulfide 2.01 g of sodium thiosulfate, Na2S2O3 The mass fraction of an element present in a compound can be obtained by comparing the mass of the particular element present in 1 mole of the compound to the ________ mass of the compound.If the amount of a sample doubles, what happens to the percent composition of each element in the compound?lculate the percent by mass of each element in the following compounds. l type='a'> HClO3 i>UFl4 i>CaH2 i>Ag2S i>NaHSO3 i>MnO2 Calculate the percent by mass of each element in the following compounds. l type="a"> ZnO i>Na2S i>Mg(OH)2 i>H2O2 i>CaH2 i>K2O Calculate the percent by mass of the element listed first in the formulas for each of the following compounds. methane, CH4 sodium nitrate, NaNO3 carbon monoxide, CO nitrogen dioxide, NO2 1-octanol, C8H18O calcium phosphate, Ca3( PO4)2 3-phenyiphenol, C12H10O aluminum acetate, Al(C2H3O2)3 Calculate the percent by mass of the element listed first in the formulas for each of the following compounds. l type="a"> copper(II) bromide, CuBr2 i>copper(I) bromide, CuBr i>iron(II) chloride, FeCl2 i>iron(III) chloride, FeCl3 i>cobalt(II) iodide, Col2 i>cobalt(III) iodide, CoI3 i>tin(II) oxide, SnO i>tin(IV)oxide, SnO2 49QAP What is the mass percent of oxygen in each of the following compounds? l type='a'> carbon dioxide sodium nitrate iron(III) phosphate ammonium carbonate aluminum sulfate For each of the following samples of ionic substances, calculate the number of moles and mass of the positive ions present in each sample. l type="a"> 4.25 g of ammonium iodide, NH4I i>6.31 moles of ammonium sulfide, ( NH4)2S i>9.71 g of barium phosphide, Ba3P2 i>7.63 moles of calcium phosphate, Ca3( PO4)2 For each of the following ionic substances, calculate the percentage of the overall molar mass of the compound that is represented by the negative ions in the substance. l type='a'> ammonium sulfide calcium chloride barium oxide nickel(II) sulfate 53QAP Explain lo a friend who has not yet taken a chemistry course what is meant by the empirical formula of a compound.Give the empirical formula that corresponds to each of the following molecular formulas. l type="a"> sodium peroxide, Na2O2 i>terephthalic acid, C8H6O4 i>phenobarbital, C12H12N2O3 i>1,4-dichloro-2-butene, C4H6Cl2 Which of the following pairs of compounds have the same empirical formula? etylene, C2H2 , and benzene, C6H6 hane, C2H6 , and butane, C4H10 trogen dioxide, NO2 , and dinitrogen tetroxide, N2O4 phenyl ether, C12H10O , and phenol, C6H5OH A compound was analyzed and was found to contain the following percentages of the elements by mass: barium, 89 56%; oxygen, 10.44%. Determine the empirical formula of the compound.A compound was analyzed and was found to contain the following percentages of the elements by mass: nitrogen, 11 .64%; chlorine, 88.36%. Determine the empirical formula of the compound.A 0.59980-g sample of a new compound has been analyzed and found to contain the following masses of elements: carbon, 0.2322 g; hydrogen, 0.05848 g; oxygen, 0.3091 g. Calculate the empirical formula of the compound.A compound was analyzed and was found to contain the following percentages of the elements by mass: boron, 78.14%; hydrogen. 21 .86%. Determine the empirical formula of the compound.If a 1.271-g sample of aluminum metal is heated in a chlorine gas atmosphere, the mass of aluminum chloride produced is 6.280 g. Calculate the empirical formula of aluminum chloride.A compound was analyzed and was found to contain the following percentages of the elements by mass: tin, 45.56%; chlorine, 54.43%. Determine the empirical formula of the compound.When 3.269 g of zinc is heated in pure oxygen, the sample gains 0.800 g of oxygen in forming the oxide. Calculate the empirical formula of zinc oxide.If cobalt metal is mixed with excess sulfur and heated strongly, a sulfide is produced that contains 55.06% cobalt by mass. Calculate the empirical formula of the sulfide.If 1.25 g of aluminum metal is heated in an atmosphere of fluorine gas. 3.89 g of aluminum fluoride results. Determine the empirical formula of aluminum fluoride.If 2.50 g of aluminum metal is heated in a stream of fluorine gas, it is found that 5.28 g of fluorine will combine with the aluminum. Determine the empirical formula of the compound that results.A compound used ¡n the nuclear industry has the following composition: uranium. 67.61%; fluorine, 32.39%. Determine the empirical formula of the compound.A compound was analyzed and was found to contain the following percentages of the elements by mass: lithium. 46.46%; oxygen, 53.54%. Determine the empirical formula of the compound.A compound has the following percentage composition by mass: copper, 33.88%; nitrogen, 14.94%; oxygen, 51.18%. Determine the empirical formula of the compound.When lithium metal is heated strongly in an atmosphere of pure nitrogen, the product contains 59.78% Li and 40.22% N on a mass basis. Determine the empirical formula of the compound.A compound has been analyzed and has been found to have the following Composition: copper, 66.75%; phosphorus, 10.84%; oxygen, 22.41%. Determine the empirical formula of the compound.Tetraphenylporphyrin is a synthetic compound that resembles naturally occurring porphyrins. Porphyrins are found in hemoglobin and cytochromes, which are important to biological functions in humans. Tetraphenylporphyrin is composed of only C, H, and N atoms. Experiments show that tetraphenylporphyrin is 85.96% C and 4.92% H by mass. What is the empirical formula of tetraphenylporphyrin?When 1.00 mg of lithium metal is reacted with fluorine gas (F2) , the resulting fluoride salt has a mass of 3.73 mg. Calculate the empirical formula of lithium fluoride.Phosphorus and chlorine form two binary compounds, in which the percentages of phosphorus are 22.55% and 14.7%, respectively. Calculate the empirical formulas of the two binary phosphoruschlorine compounds.How does the molecular formula of a compound differ from the empirical formula? Can a compound’s empirical and molecular formulas be the same? Explain.76QAP A binary compound of boron and hydrogen has the following percentage composition: 78.14% boron. 21.86% hydrogen. If the molar mass of the compound is determined by experiment to be between 27 and 28 g. what are the empirical and molecular formulas of the compound?A compound with empirical formula CH was found by experiment to have a molar mass of approximately 78 g. What is the molecular formula of the compound?A compound with the empirical formula CH2 was found to have a molar mass of approximately 84 g. What is the molecular formula of the compound?A compound with empirical formula C2H5O was found in a separate experiment to have a molar mass of approximately 90 g. What is the molecular formula of the compound?A compound having an approximate molar mass of 165170 g has the following percentage composition by mass: carbon, 42.87%; hydrogen, 3.598%; oxygen, 28.55%; nitrogen, 25.00%. Determine the empirical and molecular formulas of the compound.A compound containing only sulfur and nitrogen is 69.6% S by mass. The molar mass is 184 g/mol. What is the correct name for this compound?Use the periodic table shown in Fig. 4.9 to determine the atomic mass (per mole) or molar mass of each of the substances in column 1, and find that mass in column 2. l> Column 1 Column 2 (1) molybdenum (a) 33.99 g (2) lanthanum (b) 79.9 g (3) carbon tetrabromide (c) 95.94 g (4) mercury(II)oxide (d) l25.4g (5) titanium(iV) oxide (e) 138.9 g (6) manganese(ll) chloride (f) 143.1 g (7) phosphine, (g) 156.7 g (8) tin(II) fluoride (h) 216.6 g (9) lead(II) sulfide (i) 239.3 g (10) copper(I)oxide (j) 3316g Complete the following table. l> Mass of Sample Moles of Sample Atoms in Sample 5.00 g AI td> 0.00250 mol Fe td> msp;2.61024 atoms Cu 0.00250 g Mg td> msp;2.7103 mol Na msp;1.00104 atoms U Complete the following table. l> Mass of Sample Moles of Sample Molecules in Sample Atoms in Sample 4.24 g msp;C6H6 0.224 mol msp;H2O msp;2.711022 molecules msp;CO2 1.26 mol HCl td> msp;2.211024 molecules msp;H2O 0.297 g msp;CH3OH Consider a hypothetical compound composed of elements X, Y, and Z with the empirical formula X2YZ3 . Given that the atomic masses of X, Y, and Z are 41.2, 57.7, and 63.9, respectively, calculate the percentage composition by mass of the compound. If the molecular formula of the compound is found by molar mass determination to be actually X4Y2Z6 , what is the percentage of each element present? Explain your results.A binary compound of magnesium and nitrogen is analyzed, and 1.2791 g of the compound ¡s found to contain 0.9240 g of magnesium. When a second sample of this compound is treated with water and heated, the nitrogen is driven off as ammonia, leaving a compound that contains 60.31% magnesium and 39.69% oxygen by mass. Calculate the empirical formulas of the two magnesium compounds.When a 2.11 8-g sample of copper is heated in an atmosphere in which the amount of oxygen present is restricted, the sample gains 0.2666 g of oxygen in forming a reddish-brown oxide. However, when 2.118 g of copper is heated in a stream of pure oxygen, the sample gains 0.5332 g of oxygen. Calculate the empirical formulas of the two oxides of copper.Hydrogen gas reacts with each of the halogen elements to form the hydrogen halides (HF,HCl,HBr,HI) . Calculate the per cent by mass of hydrogen in each of these compounds.Calculate the number of atoms of each element present in each of the following samples. l type='a'> 4.2 1 g of water 6.81 g of carbon dioxide 0.000221 g of benzene, C6H6 i>2.26 moles of C12H22O11 Calculate the mass in grams of each of the following samples. l type='a'> 10,000,000,000 nitrogen molecules 2.491020 carbon dioxide molecules 7.0983 moles of sodium chloride 9.012106 moles of 1 ,2-dichloroelhane, C2H4Cl2 Calculate the mass of carbon in grams, the percent carbon by mass, and the number of individual carbon atoms present in each of the following samples. l type="a"> 7.8 19 g of carbon suboxide, C3O2 i>1.531021 molecules of carbon monoxide 0.200 mole of phenol, C6H6O Find the item in column 2 that best explains or completes the statement or question in column 1. l type="a"> Column 1 i>1 amu 1008 amu mass of the “average” atom of an element number of carbon atoms in 12.01 g of carbon 6.0221023 molecules total mass of all atoms in 1 mole of a compound smallest whole-number ratio of atoms present in a molecule formula showing actual number of atoms present in a molecule product formed when any carbon-containing compound is burned in O2 i>have the same empirical formulas, but different molecular formulas Column 2 msp;6.0221023 i>atomic mass mass of 1000 hydrogen atoms benzene, C6H6 , and acetylene, C2H2 i>carbon dioxide empirical formula 1.661023g i>molecular formula molar mass 1 mole You have a sample of copper (Cu) and a sample of aluminum (Al). You have an equal number of atoms in each sample. Which of the following statements concerning the masses of the samples is true? l type='a'> The mass of the copper sample is more than twice as great as the mass of the aluminum sample. i>The mass of the copper sample is more than the mass of the aluminum sample, but it is not more than twice as great. i>The mass of the aluminum sample is more than twice as great as the mass of the copper sample. i>The mass of the aluminum sample is more than the mass of the copper sample, hut it is not more than twice as great. i>The masses of the samples are equal.Calculate the number of grams of cobalt that contain the same number of atoms as 2.24 g of iron.A compound was analyzed and found to contain the following percentages of elements by mass: carbon, 79.89%; hydrogen, 20.11%. l type='a'> Determine the empirical formula of the compound. i>Which of the following could be a molar mass of the compound? 13.018 g/mol 16.042g/mol 28.052 g/mol 30.068 g/mol 104.23 g/rnol Calculate the number of grains of lithium that contain the same number of atom as 1 .00 kg of zirconium.Given that the molar mass of carbon tetrachloride, CCl4 , is 153 g, calculate the mass in grams of 1 molecule of CCl4 .Calculate the mass in grains of hydrogen present in 2.500 g of each of the following compounds. l type="a"> benzene, C6H6 i>calcium hydride, CaH2 i>ethyl alcohol, C2H5OH i>serine, C3H7O3N f you have equal mole samples of NO2 and F2 , which of the following must be true? l type='a'> The number of molecules in each sample is the same. i>The number of atoms in each sample is the same. i>The masses of the samples are the same. i>6.0221023 molecules are present in each sample.strikingly beautiful copper compound with the common name “blue vitriol” has the following elemental composition: 25.45% Cu, 12.84% S, 4.036% H, 57.67% O. Determine the empirical formula of the compound.certain transition metal ion (Mn+) forms a compound with oxygen (MxOy) . The molar mass of the compound is 250.2 g/mol. If the charge on the transition metal ion is +3, what is the identity of the transition metal, M? l type='a'> Th Ti Hg Ru Ag 103AP 104AP 105AP f an average sodium atom weighs 22.99 amu, how many sodium atoms are contained in 1.981013 amu of sodium? What will 3.011023 sodium atoms weigh?107AP 108AP 109AP 110AP 111AP 112AP alculate the number of moles of the indicated substance present in each of the following samples. l type='a'> 1.28 g of iron(II) sulfate 5.14 mg of mercury(II) iodide 9.21 µg of tin(IV) oxide 1.26 lb of cobalt(ll) chloride 4.25 g of copper(II) nitrate f you have equal-mole samples of each of the following compounds, which compound contains the greatest number of oxygen atoms? l type='a'> magnesium nitrate dinitrogen pentoxide iron(I1I) phosphate barium oxide potassium acetate 115AP 116AP alculate the number of moles of hydrogen atoms present in each of the following samples. l type='a'> 2.71 g of ammonia 0.824 mole of water 6.25 mg of sulfuric acid 451 g of ammonium carbonate ow many anions are there in 5.00 g of calcium bromide?119AP 120AP 1.2569-g sample of a new compound has been analyzed and found to contain the following masses of elements: carbon, 0.7238 g; hydrogen, 0.07088 g; nitrogen, 01407 g; oxygen, 0.3214 g. Calculate the empirical formula of the compound.hat mass of sodium hydroxide has the same number of oxygen atoms as 100.0 g of ammonium carbonate?hen 2.004 g of calcium is heated in pure nitrogen gas. The sample gains 0.4670 g of nitrogen. Calculate the empirical formula of the calcium nitride formed.opical hydrocortisone is often used to treat a variety of skin conditions, such as insect bites, eczema, and rashes. Each molecule of hydrocortisone contains 21 atoms of carbon (plus other atoms). The mass percentage of carbon in hydrocortisone is 69.5 8%. What is the molar mass of hydrocortisone?hen 1.00 g of metallic chromium is heated with elemental chlorine gas. 3.045 g of a chromium chloride salt results. Calculate the empirical formula of the compound.hen barium metal is heated in chlorine gas, a binary compound forms that consists of 65.95% Ba and 34.05% Cl by mass. Calculate the empirical formula of the compound.127CP itamin B12 , cyancobalamin, is essential for human nutrition. Its molecular formula is C63H88CoN14O14P . A lack of this vita min in the diet can lead to anemia. Cyanocohalamin is the form of the vitamin found in vitamin supplements. l type='a'> What is the molar mass of cyanocobalamin to two decimal places? How many moles of cyanocohalamin molecules are present in 250 mg of cyanocobalamin? What is the mass of 0.60 mole of cyanocobalamin? How many atoms of hydrogen are in 1 .0 mole of cyanocobalamin? What is the mass of 1.0107 molecules of cyanocobalamin? What is the mass (in grams) of one molecule of cyanocobalamin?129CP . How many atoms of carbon are present in 1 .0 g of CH4O ? How many atoms of carbon are present in 1.0 of CH3CH2OH ? How many atoms of nitrogen are present in 25.0 g of CO( NH2)2 ?onsider samples of phosphine (PH3) , water (H2O) . Hydrogen sulfide (H2S) , and hydrogen fluoride (HF), each with a mass of 119 g. Rank the compounds from the leastto the greatest number of hydrogen atoms contained in the samples.he chemical formula for aspirin is C9H8O4 . What is the mass percent for each element in 1 mole of aspirin? (Give your answer to four significant figures.) l type="a"> carbon > % l type="a"> hydrogen > % l type="a"> oxygen > %133CP compound with molar mass 180.1 g/mol has the following composition by mass: 40.0% 6.70% 53.3% termine the empirical and molecular formulas of the compound.ercise 9.1 Calculate the moles of CO2formed when 4.30 moles of C3H8reacts with the required 21.5 moles of O2. NT Use the moles of C3H8, and obtain the mole ratio between C3H8and CO2from the balanced equation.ercise 9.2 What mass of carbon dioxide is produced when 96.1 g of propane reacts with sufficient oxygen?ercise 9.3 Calculate the mass of water formed by the complete reaction of 96.1 g of propane with oxygen.ur lab partner has made the observation that we always measure the mass of chemicals in lab, but then use mole ratios to balance equations. What if your lab partner decided to balance equations by using masses as coefficients? Is this possible? Why or why not?ercise 9.4 Hydrofluoric acid, an aqueous solution containing dissolved hydrogen fluoride, is used to etch glass by reacting with the silica, SiO2, in the glass to produce gaseous silicon tetra fluoride and liquid water. The unbalanced equation is :math>HF(aq)+SiO2(s)SiF4(g)+H2O(l) l type='a'> Calculate the mass of hydrogen fluoride needed to react with 5.68 g of silica. Hint: Think carefully about this problem. What is the balanced equation for the reaction? What is given? What do you need to calculate? Sketch a map of the problem before you do the calculations. Calculate the mass of water produced in the reaction described in part a.ercise 9.5 In Example 9.6 we answered one of the questions we posed in the introduction to this chapter. Now let’s see if you can answer the other question posed there. Determine what mass of carbon monoxide and what mass of hydrogen are required to form 6.0 kg of methanol by the reaction :math>CO(g)+2H2(g)CH3OH(l)Lithium nitride, an ionic compound containing the Li+and N3ions, is prepared by the reaction of lithium metal and nitrogen gas. Calculate the mass of lithium nitride formed from 56.0 g of nitrogen gas and 56.0 g of lithium in the unbalanced reaction. Li(s)+N2(g)Li3N(s)ercise 9.7 Titanium(IV) oxide is a white compound used as a coloring pigment. In fact, the pages in the hooks you read are white because of the presence of this compound in the paper. Solid titanium( IV) oxide can he prepared by reacting gaseous titanium( IV) chloride with oxygen gas. A second product of this reaction is chlorine gas. :math>TiCl4(g)+O2(g)TiO2(s)+Cl2(g) ppose 6.71103g of titanium(IV) chloride is reacted with 2.45103g of oxygen. Calculate the maximum mass of titanium(JV) oxide that can form.If the percent yield of TiO2 is 75%, what mass is actually formed?elate Active Learning Question 2 from Chapter 2 to the concepts of chemical stoichiometry.You are making cookies and are missing a key ingredient—eggs. You have plenty of the other ingredients, except that you have only 1.33 cups of butter and no eggs. You note that the recipe calls for 2 cups of butter and 3 eggs (plus the other ingredients) to make 6 dozen cookies. You telephone a friend and have him bring you some eggs. How many eggs do you need? If you use all the butter (and get enough eggs), how many cookies can you make? fortunately, your mend hangs up before you tell him how mans eggs you need, then he arrives, he has a surprise for you—to save time he has broken the eggs in a bowl for you. You ask him how many he brought, and he replies, All of them, but I spilled some on the way over. You weigh the eggs and find that they weigh 62.1 g. Assuming that an average egg weighs 34.21 g: How much hunger is needed to react with all the eggs? How many cookies can you make? Which will you have left over, eggs or butter? How much is kit over? Relate this question to the concepts of chemical stoichiometry.Nitrogen (N2) and hydrogen (H2)react to form ammonia (NH3). Consider the mixture of N2 and H2 in a closed container as illustrated below: Assuming the reaction goes to completion, draw a representation of the product mixture. Explain how you arrived at this representation.4ALQ ou know that chemical A reacts with chemical B. You react 10.0 g A with 10.0 g B. What information do you need to know to determine the amount of product that will be produced? Explain.f 10.0 g of hydrogen gas is reacted with 10.0 g of oxygen gas according to the equation :math>2H2+O22H2O should not expect to form 20.0 g of water. Why not? What mass of water can be produced with a complete reaction?7ALQ 8ALQ hat happens to the weight of an iron bar when it rusts? l type='a'> There is no change because mass is always conserved. i>The weight increases. i>The weight increases, hut it the rust is scraped off, the bar has the original weight. i>The weight decreases. stify your choice and, for choices you did not pick, explain what is wrong with them. Explain what it means for something to rust.10ALQ What is meant by the term mole ratio? Give an example of a mote ratio, and explain how it is used in solving a stoichiometry problem.Which would produce a greater number of moles of product: a given amount of hydrogen gas reacting with an excess of oxygen gas to produce water, or the same amount of hydrogen gas reacting with an excess of nitrogen gas to make ammonia? Support your answer.Consider a reaction represented by the following balanced equation :math>2A+3BC+4D u find that it requires equal masses of A and B so that there are no reactants left over. Which of the following is true? Justify your choice. l type='a'> The molar mass of A must be greater than the molar mass of B. i>The molar mass of A must be less than the molar mass of B. i>The molar mass of A must be the same as the molar mass of B.14ALQ Consider the balanced chemical equation :math>A+5B3C+4D en equal masses of A and B are reacted, which is limiting, A or B? Justify your choice. If the molar mass of A is greater than the molar mass of B, then A must be limiting. If the molar mass of A is less than the molar mass of B, then A must be limiting. If the molar mass of A is greater than the molar mass of B, then B must be limiting. If the molar mass of A is less than the molar mass of B, then B must be limiting.Which of the following reaction mixtures would produce the greatest amount of product, assuming all went to completion? Justify your choice. ch involves the reaction symbolized by the equation :math>2H2+O22H2O les of H2and 2 moles of O2. les of H2and 3 moles of O2. les of H2and I mole of O2. les of H2and I mole of O2. ach would produce the same amount of product.Baking powder is a mixture of cream of tartar (KHC4H4O6)and baking soda (NaHCO3). When it is placed in an oven at typical baking temperatures (as part of a cake, ¡or example), it under goes the following reaction ( CO2makes the cake rise): msp;(KHC4H4O6)(s)+NaHCO3(s)KNaC4H4O6(s)+H2O(g)+CO2(g) u decide to make a cake one clay, and the recipe calls for baking powder. Unfortunately, you have no baking powder. You do have cream of tartar and baking soda, so you use stoichiometry to figure out how much of each to mix. the following choices, which is the best way to make baking powder? The amounts given in the choices are in teaspoons (that is, you will use a teaspoon to measure the baking soda and cream of tartar). Justify your choice. sume a teaspoon of cream of tartar has the same mass as a teaspoon of baking soda. l type='a'> Add equal amounts of baking soda and cream of tartar. i>Add a bit more than twice as much cream of tartar as baking soda. i>Add a hit more than twice as much baking soda as cream of tartar. i>Add more cream of tartar than baking soda, hut not quite twice as much. i>Add more baking soda than cream of tartar, hut not quite twice as much.You have seven closed containers each with equal masses of chlorine gas (Cl2). You add 10.0 g of sodium to the first sample, 20.0 g of sodium to the second sample, and so on (adding 70.0 g of sodium to the seventh sample). Sodium and chloride react to form sodium chloride according to the equation :math>2Na(s)+Cl2(g)2NaCl(s) ter each reaction is complete, you collect and measure the amount of sodium chloride formed. A graph of your results is shown below. mg src=Images/HTML_99425-9-18ALQ_image001.jpg alt="" align="top"/> swer the following questions: l type='a'> Explain the shape of the graph. lculate the mass of NaClformed when 20.0 g of sodium is used.Calculate the mass of Cl2 , in each container. lculate the mass of NaClformed when 50.0 g of sodium is used. Identify the leftover reactant and determine its mass for parts b and d above.19ALQ 20ALQ Consider the reaction between NO(g)and O2(g)represented below. mg src=Images/HTML_99425-9-21ALQ_image001.jpg alt="" align="top"/> at is the balanced equation for this reaction, and what is the limiting reactant?hat do the coefficients of a balanced chemical equation tell us about the proportions in which atoms and molecules react on an individual (microscopic) basis?he vigorous reaction between aluminum and iodine gives the balanced equation: :math>2Al(s)+3I2(s)2AlI2(s). mg src=Images/HTML_99425-9-2QAP_image001.jpg alt="" align="top"/> at do the coefficients in this balanced chemical equation tell us about the proportions in which these substances react on a macroscopic (mole) basis?3QAP hich of the following statements is true for the reaction of nitrogen gas with hydrogen gas to produce ammonia (NH3)? Choose the best answer. l type='a'> Subscripts can be changed to balance this equation, just as they can he changed to balance the charges when writing the formula for an ionic compound. i>The nitrogen and hydrogen will not react until you have added the correct mole ratios. i>The mole ratio of nitrogen to hydrogen in the balanced equation is 1:2. i>Ammonia will not form unless 1 mole of nitrogen and 3 moles of hydrogen have been added. i>The balanced equation allows you to predict how much ammonia you will make based on the amount of nitrogen and hydrogen present.or each of the following reactions, give the balanced equation for the reaction and state the meaning of the equation in terms of the numbers of individual molecules and in terms of moles of molecules. msp;PCl3(l)+H2O(l)H3PO3(aq)+HCl(g) msp;XeF2(g)+H2O(l)Xe(g)+HF(g)+O2(g) msp;S(s)+HNO3(aq)H2SO4(aq)+H2O(l)+NO2(g) msp;NaHSO3(s)Na2SO3(s)+SO2(l)+H2O(l)or each of the following reactions, give the balanced chemical equation for the reaction and state the meaning of the equation in terms of individual molecules and in terms of moles of molecules. msp;MnO2(s)+Al(s)Mn(s)+Al2O3(s) msp;B2O3(s)+CaF2(s)BF3(g)+CaO(s) msp;NO2(g)+H2O(l)HNO3(aq)+NO(g) msp;C6H2(g)+H2C6(g)H12(g)7QAP 8QAP onsider the balanced chemical equation :math>4Al(s)+3O2(g)2Al2O3(s). at mole ratio would you use to calculate how many moles of oxygen gas would be needed to react completely with a given number of moles of aluminum metal? What mole ratio would you use to calculate the number of moles of product that would be expected if a given number of moles of aluminum metal reacts completely?Write the balanced chemical equation for the complete combustion of heptene, C7H14. In combustion, hcpLcnc reacts with oxygen to produce carbon dioxide and water. What is the mole ratio that would enable you to calculate the number of moles of oxygen needed to react exactly with a given number of moles of heptene? What mole ratios would you use to calculate how many moles of each product form from a given number of moles of heptene?For each of the following balanced chemical equations, calculate how many moles of product(s) would be produced if 0.500 mole of the first reactant were lo react completely. msp;CO2(g)+4H2(g)CH4(g)+2H2O(l) msp;BaCl2(aq)+2AgNO3(aq)2AgCl(s)+Ba(NO3)2(aq) msp;C3H8(g)+5O2(g)4H2O(l)+3CO2(g) msp;3H2SO4(aq)+2Fe(s)Fe2(SO4)3(aq)+3H2(g)12QAP For each of the following balanced chemical equations, calculate how many grams of the product(s) would be produced by complete reaction of 0.125 mole of the first reactant. msp;AgNO3(aq)+LiOH(aq)AgOH(s)+LiNO3(aq) msp;Al2(SO4)3(aq)+3CaCl2(aq)2AlCl3(aq)+3CaSO4(s) msp;CaCO3(s)+2HCl(aq)CaCl2(aq)+CO2(g)+H2O(l) msp;2C4H10(g)+13O2(g)8CO2(g)+10H2O(g)For each of the following balanced chemical equations, calculate how many moles and how many grams of each product would be produced by the complete conversion of 0.50 mole of the reactant indicated in boldface. State clearly the mole ratio used for each conversion. msp;NH3(g)+HCl(g)NH4Cl(s) msp;CH4(g)+4S(s)CS2(l)+2H2S(g) msp;PCl3(l)+3H2O(l)H3PO3(aq)+3HCl(aq) msp;NaOH(s)+CO2(g)NaHCO3(s)For each of the following unbalanced equations, indicate how many moles of the second reactant would he required to react exactly with 0.275 mole of the first reactant. State clearly the mole ratio used for the conversion. msp;Cl2(g)+KI(aq)I2(s)+KCl(aq) msp;Co(s)+P4(s)Co3P2(s) msp;Zn(s)+HNO3(aq)ZnNO3(aq)+H2(g) msp;C5H12(l)+O2(g)CO2(g)+H2O(g)For each of the following unbalanced equations, indicate how many moles of the first product are produced if 0.625 mole of the second product forms. State clearly the mole ratio used for each conversion. msp;KO2(s)+H2O(l)KOH(s) msp;SeO2(g)+H2Se(g)H2O(g) msp;CH3CH2OH(l)+O2(g)CH3CHO(aq)+H2O(l) msp;Fe2O3(s)+Al(s)Fe(l)+Al2O(s)What quantity serves as the conversion factor between the mass of a sample and how many moles the sample contains?18QAP Using the average atomic masses given inside the front cover of this book, calculate how many moles of each substance the following masses represent l type='a'> 4.15 g of silicon, Si 2.72 mg of gold(III) chloride, AuCl3 i>1.05 kg of sulfur, S1.000901 g of iron(III) chloride, FeCl3 i>5.62103g of magnesium oxide, MgO Using the average atomic masses given inside the front cover of this book, calculate the number of moles of each substance contained in the following masses. l type="a"> 2.01102g of silver 45.2 mg of ammonium sulfide 61.7 of uranium 5.23 kg of sulfur dioxide 272 g of iron(III) nitrate Using the average atomic masses given inside the front cover of this book, calculate the mass in grams of each of the following samples. l type='a'> 2.17 moles ot germanium, Ge 4.24 mmcl of Iead(II) chloride (1 mmol = 1/1000 moI) 0.0971 mole of ammonia, NH3 :math>4.26103moles of hexane, C6H14 i>1.71 moles of iodine monochloride, ICI Using the average atomic masses given inside the front cover of this hook, calculate the mass in grains of each of the following samples. l type='a'> 0.341 mole of potassium nitride 2.62 mmol of neon (1 mmol = 1/1000 mol) 0.00449 mole of manganese(II) oxide 7.18105moles of silicon dioxide 0.00021 mole of iron(III) phosphate For each of the following unbalanced equations, calculate how many moles of the second reactant would be required to react completely with 0.413 moles of the first reactant. msp;Co(s)+F2(g)CoF3(s) msp;Al(s)+H2SO4(aq)Al2(SO4)3(aq)+H2(g) msp;K(s)+H2O(l)KOH(aq)+H2(g) msp;Cu(s)+O2(g)Cu2O(s)For each of the following unbalanced equations, calculate how many moles of the second reactant would be required to react completely with 0.557 grams of the first reactant. msp;Al(s)+Br2(l)AlBr3(s) msp;Hg(g)+HClO4(aq)Hg(ClO4)2(aq)+H2(g) msp;K(s)+P(s)K3P(s) msp;CH4(g)+Cl2(g)CCl4(l)+HCl(g)For each of the following unbalanced equations, calculate how many grants of each product would be produced by complete reaction of 12.5 g of the reactant indicated in boldface. Indicate clearly the mole ratio used for the conversion. msp;TiBr4(g)+H2(g)Ti(s)+HBr(g) msp;SiH4(g)+NH3(g)Si3N4(s)+H2(g) msp;NO(g)+H2(g)+2H2O(l) msp;Cu2S(s)Cu(s)+S(g)Boron nitride reacts with iodine monofluoride i trichlorofluoro methane at 30°C to produce pure nitrogen triiodide and by-product (BF3). :math>BN+3IFNI3+BF3 l type='a'> What mass of iodine monofluoride must be used to produce 30.0 g of nitrogen triiodide? When 30.0 g of nitrogen triiodide is produced, what is the maximum mass of by-product (BF3)created?“Smelling salts,” which are used to revive someone who has fainted, typically contain ammonium carbonate, (NH4)2CO3. Ammonium carbonate decomposes readily to form ammonia, carbon dioxide, and water. The strong odor of the ammonia usually restores consciousness in the person who has tainted. The unbalanced equation is :math>(NH4)2CO3(s)NH3(g)+CO2(g)+H2O(g) lculate the mass of ammonia gas that is produced if 1 .25 g of ammonium carbonate decomposes completely.Calcium carbide, CaC2, can be produced in an electric furnace by strongly heating calcium oxide (lime) with carbon. The unbalanced equation is :math>CaO(s)+C(s)CaC2(s)+CO(g) lcium carbide is useful because it reacts readily with water to form the flammable gas acetylene, C2H2, which is used ex tensively in the welding industry. The unbalanced equation is :math>CaC2(s)+H2O(l)C2H2(g)+Ca(OH)2(s) at mass of acetylene gas, C2H2, would he produced by complete reaction of 3.75 g of calcium carbide?When elemental carbon is burned in the open atmosphere, with plenty of oxygen gas present, the product is carbon dioxide. :math>C(s)+O2(g)CO2(g) wever, when the amount of oxygen present during the burning of the carbon is restricted, carbon monoxide is more likely to result. :math>2C(s)+O2(g)CO(g) at mass of each product is expected when a 5.00-g sample of pure carbon is burned under each of these conditions?If baking soda (sodium hydrogen carbonate) is heated strongly, the following reaction occurs: :math>2NaHCO3(s)Na2CO3(s)+H2O(g)+CO2(g) lculate the mass of sodium carbonate that will remain if a 1.52-g sample of sodium hydrogen carbonate is heated.Although we usually think of substances as “burning” only in oxygen gas, the process of rapid oxidation to produce a flame may also take place in other strongly oxidizing gases. For example, when iron is heated and placed in pure chlorine gas. The iron “burns” according to the following (unbalanced) reaction: :math>Fe(s)+Cl2(g)FeCl3(s) w many milligrams of iron(III) chloride result when 15.5 mg of iron is reacted with an excess of chlorine gas?When yeast is added to a solution of glucose or fructose, the sugars are said to undergo fermentation, and ethyl alcohol is produced. :math>C6H12O6(aq)2C2H5OH(aq)+2CO2(g) is is the reaction by which wines arc produced from grape juice. Calculate the mass of ethyl alcohol, C2H5OH. Produced when 5.25 g of glucose, C6H12O6, undergoes this reaction.Sulfurous acid is unstable in aqueous solution and gradually decomposes to water and sulfur dioxide gas (which explains the choking with associated with sulfurous acid solutions). :math>H2SO3(aq)H2O(l)+SO2(s) 4.25 g of sulfurous acid undergoes this reaction, what mass of sulfur dioxide is released?Small quantities of ammonia gas can be generated in the laboratory by heating an ammonium salt with a strong base. For example, ammonium chloride reacts with sodium hydroxide according to the following balanced equation: :math>NH4Cl(s)+NaOH(s)NH3(g)+NaCl(s)+N2O(g) at mass of ammonia gas is produced if 1.39 g of ammonium chloride reacts completely?Elemental phosphorus bums in oxygen with an intensely hot flame, producing a brilliant light and clouds of the oxide product. These properties of the combustion of phosphorus have led to its being used in bombs and incendiary devices for warfare. :math>P4(s)+5O2(g)2P2O5(s) 4.95 g of phosphorus is burned, what mass of oxygen does it combine with?36QAP Ammonium nitrate has been used as a high explosive because it is unstable and decomposes into several gaseous substances. The rapid expansion of the gaseous substances produces the explosive force. :math>NH4NO3(s)N2(g)+O2(g)+H2O(g) lculate the mass of each product gas ¡f1 .25 g of ammonium nitrate reacts.If common sugars arc heated too strongly, they char as they decompose into carbon ¡md water vapor. For example, if sucrose (table sugar) is bated, the reaction is :math>C12H22O11(s)12C(s)+11H2O(g) at mass of carbon is produced if 1.19 g of sucrose decomposes completely?Thionyl chloride, SOCl2, is used as a very powerful drying agent in many synthetic chemistry experiments in which the presence of even small amounts of water would be detrimental. The unbalanced chemical equation is :math>SOCl2(l)+H2O(l)SO2(g)+HCl(g) lculate the mass of water consumed by complete reaction of 35.0 g of SOCl2.40QAP Which of the following statements is(are) true? l type='a'> A balanced equation relates the numbers of molecules of reactants and products (or numbers of moles of reactants and products). i>To convert between moles of reactants and moles of products, we use mole ratios derived from the balanced equation. i>Often reactants are not mixed in stoichiometric quantities (they do not run out” at the same time). In that case, we must use the limiting reactant to calculate the amounts of products formed. When a chemical reaction occurs, it must follow the law of conservation of mass.Explain how one determines which reactant in a process is the limiting reactant. Does this depend only on the masses of the reactant present? Give an example of how to determine the limiting reactant by using a Before-Change-After (RCA) table with a balanced chemical equation and reactant starling amounts.Consider the equation: 2A+B5C. If 10.0 g of A reacts with 5.00 g of B. how is the limiting reactant determined? Choose the best answer and explain. l type='a'> Choose the reactant with the smallest coefficient in the balanced chemical equation. So in this case, the limiting reactant is B. Choose the reactant with the smallest mass given. So in this case, the limiting reactant is The mass of each reactant must be converted to moles and then compared to the ratios in the balanced chemical equation. So in this case, the limiting reactant cannot be determined without the molar masses of A and B. The mass of each reactant must he converted to moles first. The reactant with the fewest moles present is the limiting reactant. So in this case, the limiting reactant cannot be determined without the molar masses of A and B. The mass of each reactant must be divided by their coefficients in the balanced chemical equation, and the smallest number present is the limiting reactant. So in this case, there is no limiting reactant because A and B arc used up perfectly.Balance the following chemical equation, and then answer the question below. :math>CuSO4(aq)+KI(s)CuI(s)+I2(s)+K2SO4(aq) ich reactant is the limiting reactant? Choose the best answer. th CuSO4and Kl are equally limiting because they react in a 1:1 mole ratio. i>CuSO4is the limiting reactant because only 2 moles are available compared with 4 moles of Kl. i>Kl is the limiting reactant because it is present in excess. i>Neither CuSO4 nor Kl is a limiting reactant because 6 total moles are present on the reactant side compared with 5 total moles on the product side. i>The limiting reactant cannot be determined because the starting amounts are not given.For each of the following unbalanced reactions, suppose exactly 5.00 moles of each reactant are taken. Determine which reactant is limiting, and also determine what mass of the excess reagent will remain after the limiting reactant is consumed. For each reaction, solve the problem three ways: l type='a'> Set up and use Before—Change—After (BCA) tables. i>Compare the moles of reactants to see which runs out first. i>Consider the amounts of products that can be formed by completely consuming each reactant. i>CaC2(s)+H2O(l)Ca(OH)2(s)+C2H2(g) i>AgNO3(aq)+Al(s)Ag(s)+Al(NO3)3(aq)For each of the following unbalanced chemical equations, suppose that exactly 5.00 g of each reactant is taken. Determine which reactant is limiting, and calculate what mass of each product is expected (assuming that the limiting reactant is completely consumed). msp;S(s)+H2SO4(aq)SO2(g)+H2O(l) msp;MnO2(s)+H2SO4(l)Mn(SO4)2(s)+H2O(l) msp;H2S(g)+O2(g)SO2(g)+H2O(l) msp;AgNO3(aq)+Al(s)Ag(s)+Al(NO3)3(aq)For each of the following unbalanced chemical equations, suppose 10.0 g of each reactant is taken. Show by calculation which reactant is the limiting reagent. Calculate the mass of each product that is expected. msp;C3H8(g)+O2(g)CO2(g)+H2O(g) msp;Al(s)+Cl2(g)AlCl3(s) msp;NaOH(s)+CO2(g)Na2CO3(s)+H2O(l) msp;NaHCO3(s)+HCl(aq)NaCl(aq)+H2O(l)+CO2(g)For each of the following unbalanced chemical equations, suppose that exactly 1.00 g of each reactant is taken. Determine which reactant is limiting, and calculate what mass of the product in boldface is expected (assuming that the limiting reactant is completely consumed).3 msp;CS2(l)+O2(g)CO2(g)+SO2(g) msp;NH3(g)+CO2(g)CN2H4O(s)+H2O(g) msp;H2(g)+MnO2(s)MnO(s)+H2O(g) msp;I2(l)+Cl2(g)ICI(g)For each of the following unbalanced chemical equations, suppose 1.00 g of each reactant is taken. Show by calculation which reactant is limiting. Calculate the mass of each product that is expected. l type='a'> UO2(s)+HF(aq)UF4(aq)+H2O(l) i>NaNO3(aq)+H2SO4(aq)Na2SO4(aq)+HNO3(aq) i>Zn(s)+HCl(aq)ZnCl2(aq)+H2(g) i>B(OH)3(s)+CH3OH(l)B(OCH3)3(s)+H2O(l)For each of the following unbalanced chemical equations, suppose that exactly 15.0 g of each reactant are taken. Using Before ChangeAfter (BCA) tables, determine which reactant is limiting, and calculate what mass of each product is expected. (Assume that the limiting reactant is completely consumed.) msp;Al(s)+HCl(aq)AlCl3(aq)+H2(g) msp;NaOH(aq)+CO2(g)Na2CO3(aq)+H2O(l) msp;Pb(NO3)2(aq)+HCl(aq)PbCl2(s)+NHO3(aq) msp;K(s)+I2(s)KI(s)Lead(II) carbonate, also called “white lead,” was formerly used as a pigment in white paints. However, because of its toxicity, lead can no longer he used in paints intended for residential homes. Lead(II) carbonate is prepared industrially by reaction of aqueous lead(II) acetate with carbon dioxide gas. The unbalanced equation is :math>Pb(C2H3O2)2(aq)+H2O(l)+CO2(g)PbCO3(s)+HC2H3O2(aq) ppose an aqueous solution containing 1.25 g of lead(II) acetate is treated with 5.95 g of carbon dioxide. Calculate the theoretical yield of lead carbonate.Copper(II) sulfate has been used extensively as a fungicide (kills fungus) and herbicide (kills plants). Copper(II) sulfate can be prepared in the laboratory by reaction of copper(II) oxide with sulfuric acid. The unbalanced equation is :math>CuO(s)+H2SO4(aq)CuSO4(aq)+H2O(l) 2.49 g of copper(II) oxide is treated with 5.05 g of pure sulfuric acid, which reactant would limit the quantity of copper(II) sulfate that could be produced?Lead(II) oxide from an ore can be reduced to elemental lead by heating in a furnace with carbon. :math>PbO(s)+C(s)Pb(l)+CO(g) lculate the expected yield of lead if 50.0 kg of lead oxide is heated with 50.0 kg of carbon.If steel wool (iron) is heated until it glows and is placed in a bottle containing pure oxygen, the iron reacts spectacularly to produce iron(III) oxide. msp;Fe(s)+O2(g)Fe2O3(s) 1.25 g of iron is heated and placed in a bottle containing 0.0204 mole of oxygen gas, what mass of iron(III) oxide is produced?A common method for determining how much chloride ion is present in a sample is to precipitate the chloride from an aqueous solution of the sample with silver nitrate solution and then to weigh the silver chloride that results. The balanced net ionic reaction is :math>Ag+(aq)+Cl(aq)AgCl(s) ppose a 5.45-g sample of pure sodium chloride is dissolved in water and is then treated with a solution containing 1.15 g of silver nitrate. Will this quantity of silver nitrate be capable of precipitating all the chloride ion from the sodium chloride sample?Although many sulfate salts are soluble in water, calcium sulfate is not (Table 7. 1). Therefore, a solution of calcium chloride will react with sodium sulfate solution to produce a precipitate of calcium sulfate. The balanced equation is :math>CaCl2(aq)+Na2SO4(aq)CaSO4(s)+2NaCl(aq) a solution containing 5.21 g of calcium chloride is combined with a solution containing 4.95 g of sodium sulfate, which is the limiting reactant? Which reactant is present in excess?Hydrogen peroxide is used as a cleaning agent in the treatment of cuts and abrasions for several reasons. It is an oxidizing agent that can directly kill many microorganisms: It decomposes upon contact with blood, releasing elemental oxygen gas (which inhibits the growth of anaerobic microorganisms); and it foams upon contact with blood, which provides a cleansing action. In the laboratory, small quantities of hydrogen peroxide can be prepared by the action of an acid on an alkaline earth metal peroxide, such as barium peroxide. BaO2(s)+2HCl(aq)H2O2(aq)+BaCl2(aq) What amount of hydrogen peroxide should result when 1.50 g of barium peroxide is treated with 25.0 mL of hydrochloric acid solution containing 0.0272 g of HCI per mL?Silicon carbide, SIC, is one of the hardest materials known. Surpassed in hardness only by diamond, it is sometimes known commercially as carborundum. Silicon carbide is used primarily as an abrasive for sandpaper and is manufactured by heating common sand (silicon dioxide, SiO2) with carbon in a turn ace. :math>SiO2(s)+C(s)CO(g)+SiC(s) at mass of silicon carbide should result when 1.0 kg of pure sand is heated with an excess of carbon?59QAP The text explains that one reason why the actual yield for a reaction may be less than the theoretical yield is side reactions. Suggest some other reasons why the percent yield for a reaction might not be 100%.According to his prelaboratory theoretical yield calculations, a student’s experiment should have produced 1 .44 g of magnesium oxide. When he weighed his product after reaction. Only 1.23 g of magnesium oxide was present. What is the student’s percent yield?An air bag is deployed by utilizing the following re tion the nitrogen gas produced inflates the air bag): :math>2NaN3(s)2Na(s)+3N2(g) 10.5 g of NaN1 is decomposed, what theoretical mass of sodium should be produced? If only 2.84 g of sodium is actually collected, what is the percent yield?The compound sodium thiosutfate pentahydrate. Na2SO35H2O, is important commercially to the photography business as “hypo.” because it has the ability to dissolve unreacted silver salts from photographic film during development. Sodium thiosulfate pentahydrate can be produced by boiling elemental sulfur in an aqueous solution of sodium sulfite. msp;S8(s)+Na2SO3(aq)+H2O(l)Na2S2O35H2O(s) nbalanced) at is the theoretical yield of sodium thiosulfate pentahydrate when 3.25 g of sulfur is boiled with 13.1 g of sodium sulfite? Sodium thiosulfate pentahydrate is very soluble in water. What is the percent yield of the synthesis if a student doing this experiment is able to isolate (collect) only 5.26 g of the product?Alkali metal hydroxides are sometimes used to “scrub” excess carbon dioxide from the air in closed spaces (such as submarines and spacecraft). For example, lithium hydroxide reacts with carbon dioxide according to the unbalanced chemical equation :math>LiOH(s)+CO2(g)Li2CO3(s)+H2O(g) ppose a lithium hydroxide canister contains 155 g of LiOH(s). What mass of CO2(g)will the canister be able to absorb? If it is found that after 24 hours of use the canister has absorbed 102 g of carbon dioxide, what percentage of its capacity has been reached?Although they were formerly called the inert gases, at least the heavier elements of Group 8 do form relatively stable compounds. For example, xenon combines directly with elemental fluorine at elevated temperatures in the presence of a nickel catalyst. :math>Xe(g)+2EF2(g)XeF4(s) at is the theoretical mass of xenon tetrafluoride that should form when 130. g of xenon is reacted with 100. g of F2? What is the percent yield if only 145 g of XeF4is actually isolated?Solid copper can be produced by passing gaseous ammonia over solid copper (II) oxide al high temperatures. mg src=Images/HTML_99425-9-66QAP_image001.jpg alt="" align="top"/> e other products of the reaction are nitrogen gas and water Vapor. The balanced equation for this reaction is: :math>2NH3(g)+3CuO(s)N2(g)+3Cu(s)+3H2O(g) at is the theoretical yield of solid copper that should form when 18.1 g of NH3, is reacted with 90.4 g of CuO? If only 45.3 g of copper is actually collected, what is the percent yield? mg src=Images/HTML_99425-9-66QAP_image002.jpg alt="" align="top"/>67AP 68AP 69AP When the sugar glucose, C6H12O6, is burned in air, carbon dioxide and water vapor are produced. Write the balanced chemical equation for this process, and calculate the theoretical yield of carbon dioxide when 1.00 g of glucose is burned completely.When elemental copper is strongly heated with sulfur, a mixture of CuS and Cu2Sis produced. with CuS predominating. :math>Cu(s)+S(s)CuS(s)2Cu(s)+S(s)Cu2S(s) at is the theoretical yield of CuS when 31.8 g of Cu(s) is heated with 50.0 g of S? (Assume only CuS is produced in the reaction.) What is the percent yield of CuS if only 40.0 g of CuS can be isolated from the mixture?Barium chloride solutions are used in chemical analysis for the quantitative precipitation of sulfate ion from solution. :math>Ba2+(aq)+SO42(aq)BaSO4(s) ppose a solution is known to contain on the order of 1 50 mg of sulfate ion. What mass of barium chloride should be added to guarantee precipitation of all the sulfate ion?The traditional method of analysis for the amount of chloride ion present in a sample is to dissolve the sample in water and then slowly to add a solution of silver nitrate. Silver chloride ¡s very insoluble in water, and by adding a slight excess of silver nitrate, it is possible to effectively remove all chloride ion from the sample. :math>Ag+(aq)+Cl+(aq)AgCl(s) ppose a 1.054-g sample is known to contain 10.3% chloride ion by mass. What mass of silver nitrate must be used to completely precipitate the chloride ion from the sample? What mass of silver chloride will be obtained?For each of the following reactions, give the balanced equation for the reaction and state the meaning of the equation in terms of numbers of individual molecules and in terms of moles of molecules. msp;UO2(s)+HF(aq)UF4(aq)+H2O(l) msp;NaC2H3O2(aq)+H2SO4(aq)Na2SO4(aq)+HC2H3O2(aq) msp;Mg(s)+HCl(aq)MgCl2(aq)+H2(g) msp;B2O3(s)+H2O(l)B(OH)3(aq)75AP Consider the balanced equation :math>C3H8(g)+5O2(g)3CO2(g)+4H2O(g) at mole ratio enables you to calculate the number of moles of oxygen needed to react exactly with a given number of moles of C3H8(g)? What mole ratios enable you to calculate how many moles of each product form from a given number of moles of C3H8?For each of the following balanced reactions, calculate how many moles of each product would be produced by complete conversion of 0.50 mole of the reactant indicated in boldface. Indicate clearly the mole ratio used for the conversion. msp;2H2O(l)2H2O(l)+O2(g) msp;2KClO3(s)2KCl(s)+3O2(g) msp;2Al(s)+6HCl(aq)2AlCl3(aq)+3H2(g) msp;C3H8(g)+5O2(g)3CO2(g)+4H2O(g)For each of the following balanced equations, indicate how many moles of the product could be produced by complete reaction of 1.00 g of the reactant indicated in boldface. Indicate clearly the mole ratio used for the conversion. msp;NH3(g)+HCl(g)NH4Cl(s) msp;CaO(s)+CO2(g)CaCO3(s) msp;4Na(s)+O2(g)2Na2O(s) msp;2P(s)+3Cl2(g)2PCl3(l)79AP Using the average atomic masses given inside the front cover of the text, calculate the mass in grams of each of the following samples. l type='a'> 5.0 moles of nitric acid 0.000305 mole of mercury 2.31105mole of potassium chromate 10.5 moles of’ aluminum chloride 4.9104moles of sulfur hexafluoride 1 25 moles of ammonia 0.01205 mole of sodium peroxide For each of the following incomplete and unbalanced equations, indicate how many moles of the second reactant would be required to react completely with 0. 145 mole of the first reactant. msp;BaCl2(aq)+H2SO4(aq) msp;AgNO3(aq)+NaCl(aq) msp;Pb(NO3)2(aq)+Na2CO3(aq) msp;C3H8(g)+O2(g)82AP 83AP It sodium peroxide is added to water, elemental oxygen gas is generated: :math>Na2O2(s)+H2O(l)NaOH(aq)+O2(g) ppose 3.25 g of sodium peroxide is added to a large excess of water. What mass of oxygen gas will be produced?When elemental copper is placed in a solution of silver nitrate, the following oxidationreduction reaction takes place. Forming elemental silver: :math>Cu(s)+2AgNO3(aq)Cu(NO3)2(aq)+2Ag(s) at mass of copper is required to remove all the silver from a silver nitrate solution containing 1.95 mg of silver nitrate?When small quantities of elemental hydrogen gas are needed for laboratory work, the hydrogen is often generated by chemical reaction of a metal with acid. For example, tine reacts with hydrochloric acid, releasing gaseous elemental hydrogen: :math>Zn(s)+2HCI(aq)ZnCl2(aq)+H2(g) at mass of hydrogen gas is produced when 2.50 g of zinc is reacted with excess aqueous hydrochloride acid?The gaseous hydrocarbon acetylene, C2H2, is used in welders’ torches because of the large amount of heat released when acetylene burns with oxygen. :math>2C2H2(g)+5O2(g)4CO2(g)+2H2O(g) w many grams of oxygen gas are needed for the complete combustion of 150 g of acetylene?For each of the following unbalanced chemical equations, suppose exactly 5.0 g of each reactant is taken. Determine which reactant is limiting, and calculate what mass of each product is expected, assuming that the limiting reactant is completely consumed. msp;Na(s)+Br2(l)NaBr(s) msp;Zn(s)+CuSO4(aq)ZnSO4(aq)+Cu(s) msp;NH4Cl(aq)+NaOH(aq)NH3(g)+H2O(l)+NaCl(aq) msp;Fe2O3(s)+CO(g)Fe(s)+CO2(g)For each of the following unbalanced chemical equations, suppose 25.0 g of each reactant is taken. Show by calculation which reactant is limiting. Calculate the theoretical yield in grams of the product in boldface. msp;C2H5OH(l)+O2(g)CO2(g)+H2O(l) msp;N2(g)+O2(g)NO(g) msp;NaClO2(aq)+Cl2(g)NaCl(aq) msp;H2(g)+N2(g)NH3(g)Hydrazine N2H4, emits a large quantity of energy when it reacts with oxygen, which has led to hydrazine’s use as a fuel for rockets: :math>N2H4(l)+O2(g)N2(g)+2H2O(g) w many moles of each of the gaseous products are produced when 20.0 g of pure hydrazine ¡s ignited in the presence of 20.0 g of pure oxygen? How many grams of each product are produced?Consider the following reaction: 4NH3(g)+5O2(g)4NO(g)+6H2O(g) a container were to have only 10 molecules of O2(g)and 10 molecules of NH3(g), how many total molecules (reactant and product) would be present in the container after the above reaction goes to completion? ing “microscopic” pictures, draw the total molecules present inside the container after the reaction occurs. at mass of NO(g)is present in the container after the reaction occurs? (Report your final answer to 4 significant figures.)Before going to lab, a student read in his lab manual that the percent yield for a difficult reaction to be studied was likely to be only 40% of the theoretical yield. The student’s prelab stoichiometric calculations predict that the theoretical yield should be 12.5 g. What is the student’s actual yield likely to be?Consider the following unbalanced chemical equation for the combustion of pentane (C5H12): :math>C5H12(l)+O2(g)CO2(g)+H2O(l) a 20.4-gram sample of pentane is burned in excess oxygen, what mass of water can be produced, assuming 100% yield?94CP Consider the following unbalanced chemical equation. :math>LiOH(s)+CO2(g)Li2CO3(s)+H2O(l) 67.4 g of lithium hydroxide reacts with excess carbon dioxide, what mass of lithium carbonate will be produced?Over the years, the thermite reaction has been used for welding railroad rails, in incendiary bombs, and to ignite solid fuel rocket motors. The reaction is :math>Fe2O3(s)+2Al(s)2Fe(l)+Al2O3(s) l type='a'> What mass of iron(III) oxide must be used to produce 25.69 g of iron? What mass of aluminum must be used to produce 25.69 g of iron? What is the maximum mass of aluminum oxide that could be produced along with 25.69 g of iron?Consider the following unbalanced chemical equation: :math>H2S(g)+O2(g)SO2(g)+H2O(g) termine the maximum number of moles of SO2produced from 8.0 moles of H2Sand 3.0 moIes of O2.Ammonia gas reacts with sodium metal to form sodium amide (NaNH2)and hydrogen gas. The unbalanced chemical equation for this reaction is as follows: msp;NH3(g)+Na2(s)NaNH2(g)+H2(g) suming that you start with 32.8 g of ammonia gas and 16.6 g of sodium metal and assuming that the reaction goes to completion, determine the mass (in grams) of each product.99CP he production capacity for acrylonitrile (C3H3N)in the United States is over 2 billion pounds per year. Acrylonitrile, the building block tor acrylonitrile fibers and a variety of plastics, is produced from gaseous propylene, ammonia, and oxygen: :math>2C3H6(g)+2NH3(g)+3O22C3H3N(g)+6H2O(g) l type='a'> Assuming 100% yield, determine the mass of acrylonitrile which can be produced from the mixture below: l> Mass Reactant msp;5.23102g propylene td> msp;5.00102g ammonia td> msp;1.00103g oxygen td> i>What mass of water is formed from your mixture? Calculate the mass (in grams) of each reactant after the reaction is complete.1CR erhaps the most important concept in introductory chemistry concerns what a mole of a substance represents. The mole concept will come up again and again in later chapters in this book. What does one mole of a substance represent on a microscopic, atomic basis? What does one mole of a substance represent on a macroscopic, mass basis? Why have chemists defined the mole in this manner?ow do we know that 16.00 g of oxygen Contains the same number of atoms as does 12.01 g of carbon, and that 22.99 g of sodium contains the same number of atoms as each of these? How do we know that 106.0 g of Na2CO3contains the same number of carbon atoms as does 12.01 g of carbon, hut three times as many oxygen atoms as in 16.00 g of oxygen, and twice as many sodium atoms as in 22.99 g of sodium?4CR hat is meant by the percent composition by mass for a corn pound? Describe in general terms how this information is obtained by experiment for new compounds. How can this information be calculated for known compounds?6CR 7CR 8CR 9CR Consider the unbalanced equation for the combustion of propane: :math>C3H8(g)+O2(g)CO2(g)+H2O(g) rst, balance the equation. Then, for a given amount of propane, write the mole ratios that would enable you to calculate the number of moles of each product as well as the number of moles of O2that would be involved in a complete reaction. Finally, show how these mole ratios would be applied if 0.55 mole of propane is combusted.11CR What is meant by a limiting reactant in a particular reaction? In what way is the reaction “limited”? What does it mean to say that one or more of the reactants are present in excess? What happens to a reaction when the limiting reactant is used up?13CR 14CR 15CR 16CR A compound was analyzed and was found to have the following percent composition by mass: sodium, 43.38%; carbon, 11.33%; oxygen, 45.29%. Determine the empirical formula of the compound.18CR 19CR Solid calcium carbide (CaC2)reacts with liquid water to produce acetylene gas (C2H2)and aqueous calcium hydroxide. l type='a'> Write the balanced equation for the reaction that is (occurring. including all phases. If a 100.0-g sample of calcium carbide (CaC2)is initially reacted with 50.0 g of water, which reactant is limiting? Prove that mass is conserved for the reactant amounts used in pan b.A traditional analysis for samples containing calcium ion was to precipitate the calcium ion with sodium oxalate (Na2C2O2)solution and then to collect and weigh either the calcium oxalate itself or the calcium oxide produced by heating the oxalate precipitate: :math>Ca2+(aq)+C2O42(aq)CaC2O4(s) ppose a sample contained 0.1014 g of calcium ion. What theoretical yield of calcium oxalate would be expected? If only 0.2995 g of calcium oxalate is collected, what percentage of the theoretical yield does that represent?at if energy were not conserved? How would this affect our lives?u are calculating in a chemistry problem. What if you confuse the system and the surroundings? How would this affect the magnitude of the answer you calculate? The sign?ercise 10.1 How many calories of energy correspond to 28.4 J?ercise 10.2 Calculate the joules of energy required to heat 454 g of water from 5.4 °C to 98.6 °C.ercise 10.3 A 5.63-g sample of solid gold is heated from 21 to 32 °C. How much energy (in joules and calories) is required?

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