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All Textbook Solutions for Introduction to General, Organic and Biochemistry

Problem 1-1 Multiply: (a) (6.49107)(7.22103) (b) (3.4105)(8.21011) Divide: (a) 6.0210233.10105 (b) 3.142.30105 Problem 1-2 Convert: (a) 64.0oC to Fahrenheit (b) 47oF to Celsius 1.3P Problem 1-4 Convert the speed of sound, 332 m/s to mi/h. Check your answer to see whether it is reasonable.Problem 1-5 An intensive care patient is receiving an antibiotic IV at the rate of 50. mL/h. The IV solution contains 1.5 g of the antibiotic in 1000. mL. Calculate the mg/mm of the drip. Check your answer to see if it is reasonable.Problem 1-6 The density of titanium is 4.54 g/mL. What is the mass, in grams, of 17.3 mL of titanium? Check your answer to see whether it is reasonable.Problem 1-7 An unknown substance has a mass of 56.8 g and occupies a volume of .4 mL. What is its density in g/mL? Check your answer to see whether it is reasonable.1.8P Problem 1-9 How many calories are required to heat 731 g of water from 8oC to 74oC? Check your answer to see whether it is reasonable.Problem 1-10 A 100 g piece of iron at 25oC is heated by adding 230. cal. What will be the final temperature? Check your answer to see whether it is reasonable.1.11P 1-12 The life expectancy of a citizen in the United States is 76 years. Eighty years ago it was 56 years. In your opinion, what was the major contributor to this spectacular increase in life expectancy? Explain your answer.1-13 Define the following terms: (a) Matter (b) Chemistry 1-14 In Table 1-4, you find four metals (iron, aluminum, copper, and lead) and three organic compounds (ethanol, methanol, and ether). What kind of hypothesis would you suggest about the specific heats of these chemicals?1-15 In a newspaper, you read that Dr. X claimed that he has found a new remedy to cure diabetes. The remedy is an extract of carrots. How would you classify this claim: (a) fact, (b) theory, (c) hypothesis, or (d) hoax? Explain your choice of answer.1.16P 1-17 Write in exponential notation: (a) 0.351 (b) 602.1 (c) 0.000128 (d) 628122 1-18 Write out in full: (a) 4.03 × l05 (b) 3.2 × 103 (c) 7.13 × 10-5 (d) 5.55 × 1010 1-19 Multiply: (a) (2.16 × 105) (3.08 × 1012) (b) (1.6 × 10-8) (7.2 × 108) (c) (5.87 × 1010) (6.6 × 10-27) (d)(5.2 × 10-9)(6.8 × 10-15)1.20P 1.21P 1.22P 1.23P 1.24P 1-25 How many significant figures are in the following? (a) 0.012 (b) 0.10203 (c) 36.042 (d) 8401.0 (e) 32100 (f) 0.0402 (g) 0.000012 1-26 How many significant figures are in the following? (a) 5.71 × 1013 (b) 4.4 × 105 (c) 3 × 10-6 (d) 4.000 × 10-11 (e) 5.5550 × 10-3 1-27 Round off to two significant figures: (a) 91.621 (b) 7.329 (c) 0.677 (d) 0.003249 (e) 5.88 1-28 Multiply these numbers, using the correct number of significant figures in your answer: (a) 3630.15 × 6.8 (b) 512 × 0.0081 (c) 5.79 × 1.85825 × 1.4381 1.29 Divide these numbers, using the correct number of significant figures in your answer: (a) 3.1852.08 (b) 6.53.0012 (c) 0.00357.348 1-30 Add these groups of measured numbers using the correct number of significant figures in your answer: (a) 37.4083 + 5.404 + 10916.3 + 3.94 + 0.0006 (b) 84 + 8.215 + 0.01 + 151.7 (c) 51.51 + 100.27 + 16.878 + 3.6817 1-31 In the SI system, the second is the base unit of time. We talk about atomic events that occur in picoseconds (10-12 s) or even in femtoseconds (10-15 s). But we don’t talk about megaseconds or kiloseconds; the old standards of minutes, hours, and days prevail. How many minutes and hours are 20. kiloseconds?1-32 How many grams are in the following? (a)1 kg (b) 1 mg 1-33 Estimate without actually calculating which one is the shorter distance: (a) 20 mm or 0.3 m (b) linor30mm (c) 2000 m or 1 mi 1-34 For each of these, tell which figure is closest to the correct answer: (a) A baseball bat has a length of 100 mm or 100 cm or 100 m (b) A glass of milk holds 23 cc or 230 mL or 23 L (c) A man weighs 75 mg or 75 g or 75 kg (d) A tablespoon contains 15 mL or 150 mL or 1.5 L (e) A paper clip weighs 50 mg or 50 g or 50 kg (0 Your hand has a width of 100 mm or 100 cm or 100 m (g) An audiocassette weighs 40 mg or 40 g or 40 kg 1-35 You are taken for a helicopter ride in Hawaii from Kona (sea level) to the top of the volcano Mauna Kea. Which property of your body would change during the helicopter ride? (a) height (b) weight (c) volume (d) mass 1.36P 1.37P 1-38 Make the following conversions (conversion factor are given in Table 1-3): (a) 42.6 kg to lb (b) 1.62 lb to g (c) 34 in. to cm (d) 37.2 km to mi (e) 2.73 gal to L (f) 62g to oz (g) 33.61 qt to L (h) 43.7 L to gal (i) 1.1 mi to km (j) 34.9 mL to fl oz 1.39 Make the following metric conversions: (a)964 mLto L (b)275 mm to cm (c) 45.7 kg to g (d) 475 cm to m (e)21.64 cc to mL (f) 3.29 L to cc (g)0.044 L to mL (h)711 g to kg (1) 63.7 mL to cc (j) 0.073 kg to mg (k) 83.4 m to mm (1) 361 mg to g There are 2 bottles of cough syrup available on the shelf at the pharmacy One contains 9.5 oz and the other has 300. cc. Which one has the larger volume?1-41 A humidifier located at a nursing station holds 4.00 gallons of water. How many fluid ounces of water will completely fill the reservoir?1-42 You drive in Canada where the distances are marked in kilometers. The sign says you are 80 km from Ottawa. You are traveling at a speed of 75 mi/h. Would you reach Ottawa within one hour, after one hour, or later than that?1-43 The speed limit in some European cities is 80 km/h. How many miles per hour is this?1-44 Your car gets 25.00 miles on a gallon of gas. What would be your car’s fuel efficiency in km/L?145 Children’s Chewable Tylenol contains 80. mg of acetaminophen per tablet. If the recommended dosage is 10. mg/kg, how many tablets are needed for a 70.-lb child?1-46 A patient weighs 186 lbs. She must receive an IV medication based on body weight. The order reads, “Give 2.0 mg per kilogram.” The label reads “10. mg per cc.” How many mL of medication would you give?1-47 The doctor orders administration of a drug at 120. mg per 1000. mL at 400. mL/24 h. How many mg of drug will the patient receive every 8.0 hours?1-48 The recommended pediatric dosage of Velosef is 20. mg/kg/day. What is the daily dose in mg for a child weighing 36 pounds? If the stock vial of Velosef is labeled 208 mg/mL, how many mL would be given in a daily dose?1-49 A critical care physician prescribes an IV of heparin to be administered at a rate of 1100 units per hour. The IV contains 26,000 units of heparin per liter. Determine the rate of the IV in cc/h.1-50 If an IV is mixed so that each 150 mL contains 500. mg of the drug lidocaine, how many minutes will it take for 750 mg of lidocaine to be administered if the rate is set at 5 mL/min?1-51 A nurse practitioner orders isotonic sodium lactate 50. mL/kg body mass to be administered intravenously for a 139-lb patient with severe acidosis. The rate of flow is 150 gtts/min, and the IV administration set delivers 20. gtts/mL, where the unit “gtts” stands for drops of liquid. What is the running time in minutes?1-52 An order for a patient reads Give 40. mg of pantoprazole IV and 5 g of MgSO4 IV. The pantoprazole should be administered at a concentration of 0.4 mg/mL and the MgSO4 should be administered at a concentration of 0.02 g/mL in separate IV infusion bags. What is the total fluid volume the patient has received from both IV infusions?1.53P 1.54P 1-55 Does the chemical nature of a substance change when it melts from a solid to a liquid?1-56 The volume of a rock weighing 1.075 kg is 334.5 mL. What is the density of the rock in g/mL? Express it to three significant figures.1-57 The density of manganese is 7.21 g/mL, that of calcium chloride is 2.15 g/mL, and that of sodium acetate is 1.528 g/mL. You place these three solids in a liquid, in which they are not soluble. The liquid has a density of 2.15 g/mL. Which will sink to the bottom, which will stay on the top, and which will float in the middle of the liquid?1.58 The density of titanium is 4.54 g/mL. What is the volume, in milliliters, of 163 g of titanium?1-59 An injection of 4 mg of Valium has been prescribed for a patient suffering from muscle spasms. A sample of Valium labeled 5 mg/mL is on hand. How many mL should be injected?1-60 The density of methanol at 20oC is 0.791 g/mL. What is the mass, in grams, of a 280 mL sample?1-61 The density of dichloromethane, a liquid insoluble in water, is 1.33 g/cc. If dichioromethane and water are placed in a separatory funnel, which will be the upper layer?1-62 A sample of 10.00 g of oxygen has a volume of 6702 mL. The same weight of carbon dioxide occupies 5058 mL (a) What is the density of each gas in g/L? (b) Carbon dioxide is used as a fire extinguisher to cut off the fire’s supply of oxygen. Do the densities of these two gases explain the fire-extinguishing ability of carbon dioxide?1.63P 1.64P 1-65 While you drive your car, your battery is being charged. How would you describe this process in terms of kinetic and potential energy?1-66 How many calories are required to heat the following (specific heats are given in Table 1-4)? (a) 52.7 g of aluminum from 100oC to 285oC (b) 93.6 g of methanol from —35oC to 55oC (c) 3.4 kg of lead from —33oC to 730oC (d) 71.4 g of ice from —77oC to —5oC 1-67 If 168 g of an unknown liquid requires 2750 cal of heat to raise its temperature from 26oC to 74oC, what is the specific heat of the liquid?1-68 The specific heat of steam is 0.48 cal/g oC. How many kilocalories are needed to raise the temperature of 10.5 kg of steam from 120oC to 150oC?1.69P 1-70 (Chemical Connections IA) The average lethal dose of heroin is 1.52 mg/kg of body weight. Estimate how many grams of heroin would be lethal for a 200-lb man.1.71P 1.72P 1-73 (Chemical Connections 1C) Which would make a more efficient cold compress, ethanol or methanol? (Refer to Table 1-4.)1.74P 1-75 A brain weighing 1.0 lb occupies a volume of 620 mL. What is the specific gravity of the brain?1-76 If the density of air is 1.25 10-3 g/cc, what is the mass in kilograms of the air in a room that is 5.3 m long, 4.2 m wide, and 2.0 m high?1-77 Classify these as kinetic or potential energy: (a) Water held by a dam (b) A speeding train (c) A book on its edge before falling (d) A falling book (e) Electric current in a lightbulb 1-78 The kinetic energy possessed by an object with a mass of 1 g moving with a velocity of 1 cm/s is called 1 erg. What is the kinetic energy, in ergs, of an athlete with a mass of 127 lb running at a velocity of 14.7 mi/h?1-79 A European car advertises an efficiency of 22 km/L, while an American car claims an economy of 30 mi/gal. Which car is more efficient?1.80P 1.81P 1-82 When the astronauts walked on the Moon, they could make giant leaps in spite of their heavy gear. (a) Why were their weights on the Moon so small? (b) Were their masses different on the Moon than on the Earth?1-83 Which of the following is the largest mass and which is the smallest? 41g (b)3 103mg 8.2 106g 4.1310 10-8kg 1-84 Which quantity is bigger in each of the following pairs? (a) 1 gigaton: 10. megaton (b) 10. micrometer: 1 millimeter (c) 10. centigram 200. milligram 1-85 In Japan, high-speed “bullet trains” move with an average speed of 220. km./h. If Dallas and Los Angeles were connected by such a train, how long would it take to travel nonstop between these cities (a distance of 1490. miles)?1-86 The specific heats of some elements at 25oC are as follows: aluminum = 0.215 cal/g · oC; carbon (graphite) = 0.170 caI/g oC; iron = 0.107 cal/g mercury = 0.033 1 caI/g oC. (a) Which element would require the smallest amount of heat to raise the temperature of 100 g of the element by 10oC? (b) If the same amount of heat needed to raise the temperature of 1 g of aluminum by 25oC were applied to 1 g of mercury, by how many degrees would its temperature be raised? (c) If a certain amount of heat is used to raise the temperature of 1.6 g of iron by 10oC, the temperature of 1 g of which element would also be raised by 10oC, using the same amount of heat?1-87 Water that contains deuterium rather than ordinary hydrogen (see Section 2-4D) is called heavy water. The specific heat of heavy water at 25oC is 4.2 17 J/g oC. Which requires more energy to raise the temperature of 10.0 g by 10oC, water or heavy water?1-88 One quart of milk costs 80 cents and one liter costs 86 cents. Which is the better buy?1-89 Consider butter, density 0.860 g/mL, and sand, density 2.28 g/mL. (a) If 1.00 mL of butter is thoroughly mixed with 1.00 mL of sand, what is the density of the mixture? (b) What would be the density of the mixture if 1.00 g of the same butter were mixed with 1.00 g of the same sand?1-90 Which speed is the fastest? (a) 70 mi/h (b) 140 km/h (c) 4.5 km/s (d) 48 mi/mm 1-91 In calculating the specific heat of a substance, the following data are used: mass = 92.15 g; heat = 3.200 kcal; rise in temperature = 45oC. How many significant figures should you report in calculating the specific heat?1-92 A solar cell generates 500. kJ of energy per hour. To keep a refrigerator at 4oC, one needs 250. kcal/h. Can the solar cell supply sufficient energy per hour to maintain the temperature of the refrigerator?1-93 The specific heat of urea is 1.339 J/g . If one adds 60.0 J of heat to 10.0 g of urea at 20oC, what would be the final temperature?1.94P 1-95 You receive an order for 60. mg of meperidine (Demerol) for your postsurgical patient. The inject ion syringe is prepackaged with 75 mg/mL. How many mL will you administer?1.96P 1.97P 1-98 The antifreeze-coolant compound used in cars does not have the same density as water. Would a hydrometer be useful for measuring the amount of antifreeze in the cooling system?1.99P 1.100P 1.101P 1.102P 1.103P 1.104P 1.105P 1.106P 1.107P 1.108P 1.109P 1.110P 1-111 In the hospital, your doctor orders 100. mg of medication per hour. The label on the IV bag reads 5.0 g/1000. mL. (a) How many mL should infuse each hour? (b) The IV administration set delivers 15 gtts/mL, where the unit gtts denotes drops of liquid as explained in Problem 1-5 1. The current drip rate is set to 10. gtts/min. Is this correct? If not, what is the correct drip rate?1-112 A febrile, pediatric patient weighs 42 pounds. You need to administer acetaminophen (Tylenol) 15 mg/kg. (a) How many mg will you administer? (b) The acetaminophen (Tylenol) packages come in liquid form 160 mg/5.0 mL. How many mL will you administer to your 42 pound patient?Problem 2-1 Write the formulas of compounds in which the combining ratios are as follows: (a) Sodium: chlorine: oxygen, 1:1:3 (b) Aluminum (atomic symbol Al): fluorine (atomic symbol F), 1:3 Problem 2-2 What is the mass number of an atom containing: (a) 15 protons, 15 electrons, and 16 neutrons? (b) 86 protons, 86 electrons, and 136 neutrons?Problem 2-3 Name the elements given in Problem 2-2. Write the symbols of their atomic nuclei.Problem 2-4 (a) What are the atomic numbers of mercury (Hg) and lead (Pb)? (b) How many protons does an atom of each have? (c) If both Hg and Pb have 120 neutrons in their nuclei, what is the mass number of each? (d) Write the name and the symbol of each.2.5P Problem 2-6 The atomic weight of lithium is 6.941 amu. Lithium has only two naturally occurring isotopes: lithium-6 and lithium-7. Estimate which isotope of lithium is in greater natural abundance.Problem 2-7 Write the Lewis dot structure for the element that has the following ground-state electron configuration. What is the name of this element? 1s22s22p2x2p2y2p2z3s23p1x 2.8P 9 Answer true or false. (a) Matter is divided into elements and pure substances. (b) Matter is anything that has mass and volume (occupies space). (C) A mixture is composed of two or more pure substances. (d) An element is a pure substance. (e) A heterogeneous mixture can be separated into pure substances, but a homogeneous mixture cannot. (f) A compound consists of elements combined in a fixed ratio. (g) A compound is a pure substance. (h) All matter has mass. (I) All of the 118 known elements occur naturally on Earth. (j) The first six elements in the Periodic Table are the most important for human life. (k) The combining ratio of a compound tells you how many atoms of each element are combined in the compound. (I) The combining ratio of 1:2 in the compound CO2 tells you that this compound is formed by the combination of one gram of carbon with two grams of oxygen.2.10P 2.11P 2-12 The elements game, Part 1. Name and give the symbol of the element that is named for each person. (a) Niels Bohr (1885—1962), Nobel Prize for physics in 1922 (b) Pierre and Marie Curie, Nobel Prize for chemistry in 1903 (c) Albert Einstein (1879—1955), Nobel Prize for physics in 1921 (d) Enrico Fermi (1901—1954), Nobel Prize for physics in 1938 (e) Ernest Lawrence (1901—1958), Nobel Prize for physics in 1939 (f) Lise Meitner (1868—1968, codiscoverer of nuclear fission (g) Dmitri Mendeleyev (1834—1907), first person to formulate a workable Periodic Table h) Alfred Nobel (1833—1896), discoverer of dynamite (i) Ernest Rutherford (1871—1937), Nobel Prize for chemistry in 1908 (j) Glen Seaborg (1912—1999), Nobel Prize for chemistry in 1951 2.13P 2.14P 2.15P 2.16P 2-17 How does Dalton’s atomic theory explain: (a) the law of conservation of mass? (b) the law of constant composition?2.18P 2.19P 2-20 Calculate the percentage of hydrogen and oxygen in water, H2O, and hydrogen peroxide, H2O2.2.21P 2.22P 2-23 It has been said, “The number of protons determines the identity of the element.” Do you agree or disagree with this statement? Explain.2.24P 2.25P 2-26 Given these mass numbers and number of neutrons, what is the name and symbol of each element? (a) Mass number 45; 24 neutrons (b) Mass number 48; 26 neutrons (c) Mass number 107; 60 neutrons (d) Mass number 246; 156 neutrons (e) Mass number 36; 18 neutrons 2-27 If each atom in Problem 2-26 acquired two more neutrons, what element would each then be?2.28P 2-29 How many protons and how many neutrons does each of these isotopes of radon contain? (a) Rn-210 (b) Rn-218 (c) Rn-222 2.30P 2-31 Tin-118 is one of the isotopes of tin. Name the isotopes of tin that contain two, three, and six more neutrons than tin-118.2.32P 2.33P 2-34 There are only two naturally occurring isotopes of antimony. 121Sb (120.90 amu) and 123Sb (122.90 amu). The atomic weight of antimony given in the Periodic Table is 121.75. Which of the two isotopes has the greater natural abundance?2-35 The two most abundant naturally occurring isotopes of carbon are carbon-12 (98.90%, 12.000 amu) and carbon-13 (1.10%, 13.003 amu). From these abundances, calculate the atomic weight of carbon and compare your calculated value with that given in the Periodic Table.2.36P 2.37P 2.38P 2.39P 2.40P 2.41P 2.42P 2-43 Which group(s) of the Periodic Table contain(s): (a) Only metals? (b) Only metalloids? (c) Only nonmetals?2-44 Which period(s) in the Periodic Table contain(s) more nonmetals than metals? Which contain(s) more metals than nonmetals?2.45P 2.46P 2-47 Which element in each pair is more metallic? (a) Silicon or aluminum (b) Arsenic or phosphorus (c) Gallium or germanium (d) Gallium or aluminum 2.48P 2.49P 2.50P 2-51 What is the correlation between the group number of the main-group elements (those in the A columns of the Mendeleyev system) and the number of valence electrons in an element in the group?2.52P 2.53P 2.54P 2.55P 2.56P 2.57P 2.58P 2-59 You are presented with a Lewis dot structure of element X as X.. To which two groups in the Periodic Table might this element belong?2.60P 2.61P 2.62P 2.63P 2-64 Consider the elements B, C, and N. Using only the Periodic Table, predict which of these three elements has: (a) the largest atomic radius. (b) the smallest atomic radius. (c) the largest ionization energy (d) the smallest ionization energy 2.65P 2.66P 2-67 Account for the fact that the first ionization energy of oxygen is less than that of nitrogen.2.68P 2-69 (Chemical Connections 2A) Why does the body need sulfur, calcium, and iron?2.70P 2.71P 2.72P 2-73 (Chemical Connections 2D) Copper is a soft metal. how can it be made harder?2.74P 2.75P 2.76P 2.77P 2.78P 2.79P 2.80P 2.81P 2.82P 2-83 The natural abundance of boron isotopes is as follows: 19.9sf boron-l0 (10.013 amu) and 80.1% boron-11 (11.009 amu). Calculate the atomic weight of boron (watch the significant figures) and compare your calculated value with that given in the Periodic Table.2.84P 2-85 The mass of a proton is 1.67 × 10-24g. The mass of a grain of salt is 1.0 × 10-2g. How many protons would it take to have the same mass as a grain of salt?2.86P 2.87P 2.88P 2-89 Assume that a new element has been discovered with atomic number 117. Its chemical properties should be similar to those of astatine (At). Predict whether the new element’s ionization energy will be greater than, the same as, or smaller than that of: (a)At (b)Ra 2.90P 2-91 These are the first two ionization energy for lithium: Li(g) Li+(g) + e-(g) Ionization energy = 523 kJ/mol Li+(g) Li2+(g) + e-(g) Ionization energy = 7298 kJ/mol (a) Explain the large increase in ionization energy that occurs for the removal of the second electron. (b) The radius of Li is 78 pm (1 pm = 10-12 m) while that of a lithium atom, Li, is 152 pm. Exp lain why the radius of Li is so much smaller than the radius of Li.2.92P 2.93P 2-94 Using your knowledge of trends in element sizes in going across a period of the Periodic Table, exp lain why the density of the elements increases from potassium through vanadium. (Recall from Section 1-7 that specific gravity is numerically the same as density but has no units.) Element Specific Gravity K 0.862 Ca1.55 Se 2.99 Ti 4.54 V 6.11 2.95P 2.96P 2-97 Explain why the Ca3+ ion is not found in chemical compounds.2-98 Explain how the ionization energy of atoms changes when proceeding down a group of the Periodic Table and explain why this change occurs.2-99 A 7.12 g sample of magnesium is heated with 1.80 g of bromine. All the bromine is used up, and 2.07 g of magnesium bromide is produced. What mass of magnesium remains unreacted?2-100 A 0.100 g sample of magnesium, when combined with oxygen, yields 0.166 g of magnesium oxide. What masses of magnesium and oxygen must be combined to make exactly 2.00 g of magnesium oxide?2-101 Complete the following table: Symbol Atomic number Atomic weight Mass number # of protons # of neutrons # of electrons H 0 Li 4 3 Al 26 58 78 17 20 2-102 An element consists of 90.51% of an isotope with a mass of 19.992 amu, 0.27% of an isotope with a mass of 20.994 amu, and 9.22% of an isotope with a mass of 21.990 amu. Calculate the average atomic mass and identify the element.2-103 The element silver has two naturally occurring isotopes: 109Ag and 107Ag with a mass of 106.905 amu. Silver consists of 51.82% 07Ag and has an average atomic mass of 107.868 amu. Calculate the mass of 109Ag 2-104 The average atomic weight of lithium is 6.941 amu. The two naturally occurring isotopes of lithium have the following masses: 6Li, 6.01512 amu; 7Li, 7.01600 amu. Calculate the percent abundance of 6Li and 7Li in naturally occurring lithium.2.105P 2.106P Problem 3-1 Show how the following chemical changes obey the octet rule: (a) A magnesium atom forms a magnesium ion, Mg2+. (b) A sulfur atom forms a sulfide ion, S2-.Problem 3-2 Judging from their relative positions in the Periodic Table, which element in each pair has the larger electronegativity? (a) Lithium or potassium (b) Nitrogen or phosphorus (c) Carbon or silicon Problem 3-3 Write the formulas for the ionic compounds formed from the following ions: (a) Potassium ion and chloride ion (b) Calcium ion and fluoride ion (c) Iron(III) ion and oxide ion Problem 3-4 Name these binary ionic compounds: (a) MgO ( b) BaI2 (c) KCl 3.5P Problem 3-6 Give each binary compound a systematic name and a common name. (a) FeO (b) Fe2O3 Problem 3-7 Name these ionic compounds, each of which contains a polyatomic ion: (a) K2HPO4 (b) Al2(SO4)3 (c) FeCO3 3.8P 3.9P 3.10P 3.11P 3.12P 3.13P 3.14P Problem 3-15 Predict all bond angles for these molecules: (a) CH3OH (b) CH2Cl2 (c) H2CO3 (carbonic acid)Problem 3-16 Which of these molecules are polar? Show the direction of the molecular dipole by using an arrow with a crossed tail. (a) H2S (b) HCN (C) C2H6 3-17 Answer true or false. (a) The octet rule refers to the chemical bonding patterns of the first eight elements of the Periodic Table. (b) The octet rule refers to the tendency of certain elements to react in such a way that they achieve an outer shell of eight valence electrons. (c) In gaining electrons, an atom becomes a positively charged ion called a cation. (d) When an atom forms an ion, only the number of valence electrons changes; the number of protons and neutrons in the nucleus does not change. (e) In forming ions, Group 2A elements typically lose two electrons to become cations with a charge of + 2. (f) In forming an ion, a sodium atom (1s22s22p63s1) completes its valence shell by adding one electron to fill its 3s shell (1s2 2s2 2p63s2). (g) The elements of Group 6A typically react by accepting two electrons to become anions with a charge of 2. (h) With the exception of hydrogen, the octet rule applies to all elements in periods 1,2, and 3. (i) Atoms and the ions derived from them have very similar physical and chemical properties.3-18 How many electrons must each atom gain or lose to acquire an electron configuration identical to the noble gas nearest to it in atomic number? (a) Li (b) Cl (c) P (d) Al (e) Sr (f) S (g) Si (h) O 3-19 Show how each chemical change obeys the octet rule. (a) Lithium forms Li+ ( b) Oxygen forms O2-3-20 Show how each chemical change obeys the octet rule. (a) Hydrogen forms W- (hydride ion) (b) Aluminum forms Al3+3-21 Write the formula for the most stable ion formed by each element. (a) Mg (b) F (c) Al (d)S (e)K (f) Br 3-22 Why is Li- not a stable ion?3-23 Predict which ions are stable: (a) (b) (c) (d) (e) (f)3-24 Predict which ions are stable: (a) Br2- (b) C4- (c) Ca+ (d) Ar+ (e) Na+ (f) Cs+3-25 Why are carbon and silicon reluctant to form ionic bonds?3-26 Table 3-2 shows the following ions of copper: Cu+ and Cu2+. Do these violate the octet rule? Explain.3-27 Answer true or false. (a) For Group lA and Group 2A elements, the name of the ion each forms is simply the name of the element followed by the word ion; for example, Mg is named magnesium ion. (b) W is named hydronium ion, and W is named hydride ion. (c) The nucleus of H consists of one proton and one neutron. (d) Many transition and inner transition elements form more than one positively charged ion. (e) In naming metal cations with two different charges, the suffix-ous refers to the ion with a charge of +1 and _ic refers to the ion with a charge of +2. (f) Fe32 may be named either iron(III) ion or ferric ion. (g) The anion derived from a bromine atom is named bromine ion. (h) The anion derived from an oxygen atom is named oxide ion. (i) HCO3- is named hydrogen carbonate ion. (j) The prefix bi- in the name “bicarbonate” ionindicates that this ion has a charge of 2. (k) The hydrogen phosphate ion has a charge of +1, and the dihydrogen phosphate ion has a charge of +2. (l) The phosphate ion is PO34-. (m) The nitrite ion is NO2, and the nitrate ion is NO3. (n) The carbonate ion is CO, and the hydrogen carbonate ion is HCO3-.3-28 Name each polyatomic ion. (a) HCO3- (b) NO2- (c) SO42- (d) HSO4- (e) H2PO4-3-29 Answer true or false. (a) According to the Lewis model of bonding, atoms bond together in such a way that each atom participating in the bond acquires an outer-shell electron configuration matching that of the noble gas nearest to it in atomic number. (b) Atoms that lose electrons to achieve a filled valence shell become cations and form ionic bonds with anions. (c) Atoms that gain electrons to achieve filled valence shells become anions and form ionic bonds with cations. (d) Atoms that share electrons to achieve filled valence shells form covalent bonds. (e) Ionic bonds tend to form between elements on the left side of the Periodic Table, and covalent bonds tend to form between elements on the right side of the Periodic Table. (f) Ionic bonds tend to form between a metal and a nonmetal. (g) When two nonmetals combine, the bond between them is usually covalent. (h) Electronegativity is a measure of an atom’s at traction for the electrons it shares in a chemical bond with another atom. (j) Electronegativity generally increases with atomic number. (j) Electronegativity generally increases with atomic weight. (k) Electronegativity is a periodic property. (l) Fluorine, in the upper-right corner of the Periodic Table, is the most electronegative element; hydrogen, in the upper-left corner, is the least electronegative element. (m)Electronegativity depends on both the nuclear charge and the distance of the valence electrons from the nucleus. (n) Electronegativity generally increases from left to right across a period of the Periodic Table. (o) Electronegativity generally increases from top to bottom in a column of the Periodic Table.3.30P 3-31 Why does electronegativity generally increase going from left to right across a row of the Periodic Table?3-32 Judging from their relative positions in the Periodic Table, which element in each pair has the larger electronegativity? (a)F or Cl (b) O or S (c) C or N (d) C or F 3.33P 3-34 Which of these bonds is the most polar? The least polar? (a) CN (b) CC (c) CO 3-35 Classify each bond as nonpolar covalent, polar covalent, or ionic. (a) CCl (b) CLi (c) CN 3-36 Classify each bond as nonpolar covalent, polar covalent, or ionic. (a) CBr ( b) SCl (c) CP 3-37 Answer true or false. (a) An ionic bond is formed by the combination of positive and negative ions. (b) An ionic bond between two atoms forms by the transfer of one or more valence electrons from the atom of higher electronegativity to the atom of lower electronegativity. (c) As a rough guideline, we say that an ionic bond will form if the difference in electronegativity between two atoms is approximately 1.9 or greater. (d) In forming NaCl from sodium and chlorine atoms, one electron is transferred from the valence shell of sodium to the valence shell of chlorine. (e) The formula of sodium sulfide is Na2S. (f) The formula of calcium hydroxide is CaOH. (g) The formula of aluminum sulfide is MS. (h) The formula of iron(III) oxide is Fe2O2. (j) Barium ion is Ba2, and oxide ion is O2-; there fore, the formula of barium oxide is Ba2O2.3-38 Complete the chart by writing formulas for the compounds formed: Br- MnO4- O2- NO3- SO42- PO43- OH- Li+ Ca2+ Co3+ K+ Cu2+3-39 Write a formula for the ionic compound formed from each pair of elements. (a) Sodium and bromine (b) Sodium and oxygen (c) Aluminum and chlorine (d) Barium and chlorine (e) Magnesium and oxygen 3.40P 3-41 Describe the structure of sodium chloride in the solid state.3-42 What is the charge on each ion in these compounds? (a) CaS (b) MgF2 (c) Cs2O (d) ScCl3 (e) Al2S3 3-43 Write the formula for the compound formed from the following pairs of ions: (a) Iron(III) ion and hydroxide ion (b) Barium ion and chloride ion (c) Calcium ion and phosphate ion (d) Sodium ion and permanganate ion 3-44 Write the formula for the ionic compound formed from the following pairs of ions: (a) Iron(II) ion and chloride ion (b) Calcium ion and hydroxide ion (c) Ammonium ion and phosphate ion (d) Tin(II) ion and fluoride ion 3-45 Which formulas are not correct? For each that is not correct, write the correct formula. (a) Ammonium phosphate; (NH4 )2PO4 (b) Barium carbonate; Ba2CO3 (c) Aluminum sulfide; Al2S3 (d) Magnesium sulfide; MgS 3-46 Which formulas are not correct? For each that is not correct, write the correct formula. (a) Calcium oxide; CaO2 (b) Lithium oxide; LiO (c) Sodium hydrogen phosphate; NaHPO4 (d) Ammonium nitrate; NH4NO3 3-47 Answer true or false. (a) The name of a binary ionic compound consists of the name of the positive ion followed by the name of the negative ion. (b) In naming binary ionic compounds, it is necessary to state the number of each ion present in the compound. (c) The formula of aluminum oxide is AL2O3. (d) Both copper(II) oxide and cupric oxide are acceptable names for CuO. (e) The systematic name for Fe2O3 is iron(II) oxide. (f) The systematic name for FeCO3 is ironcarbonate. (g) The systematic name for NaH2PO4 is sodium dihydrogen phosphate. (h) The systematic name for K,HPO4 is dipotassium hydrogen phosphate. (i) The systematic name for Na20 is sodium oxide. (j) The systematic name for PCL3 is potassium chloride. (k) The formula of ammonium carbonate is NH4CO3.3-48 Potassium chloride and potassium bicarbonate are used as potassium dietary supplements. Write the formula of each compound.3.49P 3-50 Name the polyatomic ion(s) in each compound. (a) Na2SO3 (b) KNO3 (c) Cs2CO3 (d) NH4OH (e) K2HPO4 (f) Ca(ClO4)2 3-51 Write the formulas for the ions present in each compound. (a) NaBr (b) FeSO3 (c) Mg3(PO4)2 (d) KH2PO4 (e) NaHCO3 (f) Ba(NO3)2 3.52P 3-53 Write formulas for the following ionic compounds: (a) Potassium bromide (b) Calcium oxide (c) Mercury(I1) oxide (d) Copper(II) phosphate (e) Lithium sulfate (f) Iron(III) sulfide 3-54 Write formulas for the following ionic compounds: (a) Ammonium hydrogen sulfite (b) Magnesium acetate (c) Strontium dihydrogen phosphate (d) Silver carbonate (e) Strontium chloride (f) Barium permanganate (g) Aluminum perchiorate 3.55P 3-56 How many covalent bonds are normally formed by each element? (a)N ( b)F (c)C (d)Br (e)O 3-57 What is: (a) A single bond? (b) A double bond? (c) A triple bond?3-58 In Section 2-3B, we saw that there are seven diatomic elements. (a) Draw Lewis structures for each of these diatomic elements. (b) Which diatomic elements are gases at room temperature? Which are liquids? Which are solids?3.59P 3.60P 3.61P 3.62P 3-63 What is the difference between (a) a bromine atom, (b) a bromine molecule, and (c) a bromide ion? Draw the Lewis structure for each.3-64 Acetylene (C2H2), hydrogen cyanide (HCN), and nitrogen (N2) each contain a triple bond. Draw a Lewis structure for each molecule. Which of these are polar molecules, and which are nonpolar molecules?3.65P 3-66 Why can’t second-row elements have more than eight electrons in their valence shells? That is, why does the octet rule work for second-row elements?3-67 Why does nitrogen have three bonds and one unshared pair of electrons in covalent compounds?3-68 Draw a Lewis structure of a covalent compound in which nitrogen has: (a) Three single bonds and one unshared pair of electrons (b) One single bond, one double bond, and one unshared pair of electrons (c) One triple bond and one unshared pair of electrons 3.69P 3-70 Draw a Lewis structure of a covalent compound in which oxygen has: (a) Two single bonds and two unshared pairs of electrons (b) One double bond and two unshared pairs of electrons 3.71P 3.72P 3.73P 3-74 Answer true or false. (a) A binary covalent compound contains two kinds of atoms. (b) The two types of atoms in a binary covalent compound are named in this order: first the more electronegative element and then the less electronegative element. (c) The name for SF2 is sulfur difluoride. (d) The name for CO2 is carbon dioxide. (e) The name for CO is carbon oxide. (f) The name for HBr is hydrogen bromide. (g) The name for CCl4 is carbon tetrachioride.3.75P 3.76P 3-77 Ozone, O3, is an unstable blue gas with a characteristic pungent odor. In an ozone molecule, the connectivity of the atoms is OOO and both OO bonds are equivalent. (a) How many valence electrons must be present in an acceptable Lewis structure for an ozone molecule? (b) Write two equivalent resonance contributing structures for ozone. Be certain to show any positive or negative charges that may be present in your contributing structures. By equivalent contributing structures, we mean that each has the same pattern of bonding. (c) Show by the use of curved arrows how the first of your contributing structures may be converted to the second. (d) Based on your contributing structures, predict the OOO bond angle in ozone. (e) Explain why the following is not an acceptable contributing structure for an ozone molecule:3-78 Nitrous oxide, N20, laughing gas, is a colorless, nontoxic, tasteless, and odorless gas. It is used as an inhalation anesthetic in dental and other surgeries. Because nitrous oxide is soluble in vegetable oils (fats), it is used commercially as a propellant in whipped toppings Nitrous oxide dissolves in fats. The gas is added under pressure to cans of whipped topping. When the valve is opened, the gas expands, thus expanding (whipping) the topping and forcing it out of the can. (a) How many valence electrons are present in a molecule of N20? (b) Write two equivalent contributing structures for this molecule. The connectivity in nitrous oxide is NNO. (c) Explain why the following is not an acceptable contributing structure:3-79 Answer true or false. (a) The letters VSEPR stand for valence-shell electron-pair repulsion. (b) In predicting bond angles about a central atom in a covalent molecule, the VSEPR model considers only shared electron pairs (electron pairs involved in forming covalent bonds). (c) The VSEPR model treats the two electron pairs of a double bond as one region of electron density and the three electron pairs of a triple bond as one region of electron density. (d) In carbon dioxide, OCO, carbon is surrounded by four pairs of electrons and the VSEPR model predicts 109.5° for the OCO bond angle. (e) For a central atom surrounded by three regions of electron density, the VSEPR model predicts bond angles of 120°. (f) The geometry about a carbon atom surrounded by three regions of electron density is described as trigonal planar. (g) For a central atom surrounded by four regions of electron density, the VSEPR model predicts bond angles of 360°/4 = 90°. (h) For the ammonia molecule, NH3, the VSEPR model predicts HNH bond angles of 109.5°. (i) For the ammonium ion, NH4, the VSEPR model predicts HNH bond angles of 109.5°. (j) The VSEPR model applies equally well to covalent compounds of carbon, nitrogen, and oxygen. (k) In water, HOH, the oxygen atom forms covalent bonds to two other atoms, and therefore, the VSEPR model predicts an HOH bond angle of 180°. (l) If you fail to consider unshared pairs of valence electrons when you use the VSEPR model, you will arrive at an incorrect prediction. (m) Given the assumptions of the VSEPR model, the only bond angles it predicts for compounds of carbon, nitrogen, and oxygen are 109.5°, 120°, and 180°.3.80P 3.81P 3-82 Hydrogen and nitrogen combine in different ratios to form three compounds: NH3 (ammonia), N2H4(hydrazine), and N2H2 (diimide). (a) How many valence electrons must the Lewis structure of each molecule show? (b) Draw a Lewis structure for each molecule. (c) Predict the bond angles about the nitrogen atom(s) in each molecule.

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