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All Textbook Solutions for Chemistry

Define and explain the differences between the following terms. a. law and theory b. theory and experiment c. qualitative and quantitative d. hypothesis and theory Is the scientific method suitable for solving problems only in the sciences? Explain.Which of the following statements could be tested by quantitative measurement? a. Ty Cobb was a better hitter than Pete Rose. b. Ivory soap is 99.44% pure. c. Rolaids consumes 47 times its weight in excess stomach acid.For each of the following pieces of glassware, provide sample measurement and discuss the number of significant figures and uncertainty.A student performed an analysis of a sample for its calcium content and got the following results: 14.92% 14.91% 14.88% 14.91% The actual amount of calcium in the sample is 15.70%. What conclusions can you draw about the accuracy and precision of these results?Compare and contrast the multiplication/division significant figure rule to the significant figure rule applied for addition/subtraction in mathematical operations.Explain how density can be used as a conversion factor to convert the volume of an object to the mass of the object, and vice versa.On which temperature scale (F, C. or K) docs 1 degree represent the smallest change in temperature?Distinguish between physical changes and chemical changes.Why is the separation of mixtures into pure or relatively pure substances so important when performing a chemical analysis?a. There are 365 days per year, 24 hours per day, 12 months per year, and 60 minutes per hour. Use these data (o deter- mine how many minutes are in a month. b. Now use the following data to calculate the number of minutes in a month: 24 hours per day, 60 minutes per hour, 7 days per week, and 4 weeks per month. c. Why are these answers different? Which (if any) is more correct? Why?2ALQ When a marble is dropped into a beaker of water, it sinks to the bottom. Which of the following is the best explanation? a. The surface area of the marble is not large enough to be held up by the surface tension of the water. b. The mass of the marble is greater than that of the water. c. The marble weighs more than an equivalent volume of the water. d. The force from dropping the marble breaks the surface tension of the water. e. The marble has greater mass and volume than the water. Justify your choice, and for choices you did not pick, explain what is wrong about them.4ALQ You may have noticed that when water boils, you can see bubbles that rise to the surface of the water. a. What is inside these bubbles? i. air ii. hydrogen and oxygen gas iii. oxygen gas iv. water vapor v. carbon dioxide gas b. Is the boiling of water a chemical or physical change? Explain.If you place a glass rod over a burning candle, the glass appears to turn black. What is happening to each of the following (physical change, chemical change, both, or neither) as the candle bums? Explain each answer, a. the wax b. the wick c. the glass rod Which characteristics of a solid, a liquid, and a gas are exhibited by each of the following substances? How would you classify each substance? a. a bowl of pudding b. a bucketful of sand Sketch a magnified view (showing atoms/molecules) of each of the following and explain: a. a heterogeneous mixture of two different compounds b. a homogeneous mixture of an element and a compound Paracelsus, a sixteenth-century alchemist and healer, adopted as his slogan: "The patients are your textbook, the sickbed is your study. Is this view consistent with using the scientific method?What is wrong with the following statement? "The results of the experiment do not agree with the theory. Something must be wrong with the experiment."Why is it incorrect to say that the results of a measurement were accurate but not precise?You have a 1.0-cm3 sample of lead and a 1.0-cm3 sample of glass. You drop each in separate beakers of water. How do the volumes, of water displaced by each sample compare? Explain.Consider the addition of 15.4 to 28. What would a mathematician say the answer is? What would a scientist say? Justify the scientists answer, not merely citing the rule, but explaining it.Consider multiplying 26.2 by 16.43. What would a mathematician say the answer is? What would a scientist say? Justify the scientist's answer, not merely citing the rule, but explaining it.True or false? For mathematical operation performed on two measurements, the number of significant figures in the answer is the same as the least number of significant figures in either of the measurements. Explain your answer.Is there a difference between a homogeneous mixture of hydrogen and oxygen in a 2:1 ratio and a sample of water vapor? Explain.The difference between a law and a theory is the difference between what and why. Explain.The scientific method is a dynamic process. What does this mean?Explain the fundamental steps of the scientific method.22Q A measurement is a quantitative observation involving both a number and a unit. What is a qualitative observation? What are the SI units for mass, length, and volume? What is the assumed uncertainty in a number (unless stated otherwise)? The uncertainty of a measurement depends on the precision of the measuring device. Explain.To determine the volume of a cube, a student measured one of the dimensions of the cube several times. If the true dimension of the cube is 10.62 cm, give an example of four sets of measurements that would illustrate the following, a. imprecise and inaccurate data b. precise but inaccurate data c. precise and accurate data Give a possible explanation as to why data can be imprecise or inaccurate. What is wrong with saying a set of measurements is imprecise but accurate?What are significant figures? Show how to indicate the number one thousand to 1 significant figure, 2 significant figures, 3 significant figures, and 4 significant figures. Why is the answer, to the correct number of significant figures, not 1.0 for the following calculation? 1.5-1.00.50=A cold front moves through and the temperature drops by 20 degrees. In which temperature scale would this 20 degree change represent the largest change in temperature?In a multiple-step calculation, is it better to round off the numbers to the correct number of significant figures in each step of the calculation or to round off only the final answer?Is the density of a gaseous substance larger or smaller than the density of a liquid or a solid at the same temperature? Why?Give four examples illustrating each of the following terms. a. homogeneous mixture b. heterogeneous mixture c. compound d. element e. physical change f. chemical change Which of the following are exact numbers? a. There are 100 cm in 1 m. b. One meter equals 1.094 yards. c. We can use the equation F=95C+32 to convert from Celsius to Fahrenheit temperature. Are the numbers 95 and 32 exact or inexact? d. = 3.1415927.Indicate the number of significant figures in each of the following: a. This book contains more than 1000 pages. b. A mile is about 5300 ft. c. A liter is equivalent to 1.059 qt. d. The population of the United States is approaching 3.1 102 million. e. A kilogram is 1000 g. f. The Boeing 747 cruises at around 600 mi/h.How many significant figures are there in each of die following values? a. 6.07 1015 b. 0.003840 c. 17.00 d. 8 108 e. 463.8052 f. 300 g. 301 h. 300.How many significant figures are in each of the following? a. 100 b. 102 c. 103 d. 100. e. 0.0048 f. 0.00480 g. 4.80 103 h. 4.800 103 Round off each of the following numbers to the indicated number of significant digits, and write the answer in standard scientific notation. a. 0.00034159 to three digits b. 103.351 102 to four digits c. 17.9915 to five digits d. 3.365 105 to three digits Use exponential notation to express the number 385,500 to a. one significant figure. b. two significant figures. c. three significant figures. d. five significant figures.You have liquid in each graduated cylinder shown: You then add both samples to a beaker. How would you write the number describing the total volume? What limits the precision of this number?The beakers shown below have different precisions. a. Label the amount of water in each of the three beakers to the correct number of significant figures. b. Is it possible for each of the three beakers to contain the exact same amount of water? If no, why not? If yes, did you report the volumes as the same in part a? Explain. c. Suppose you pour the water from these three beakers into one container. What should be the volume in the container reported to the correct number of significant figures?Evaluate each of the following, and write the answer to the appropriate number of significant figures. a. 212.2 + 26.7 + 402.09 b. 1.0028 + 0.221 + 0.10337 c. 52.331 + 26.01 0.9981 d. 2.01 102 + 3.014 103 e. 7.255 6.8350 Perform the following mathematical operations, and express each result to the correct number of significant figures. a. 0.1020.08212731.01 b. 0.14 6.022 1023 c. 4.0 104 5.021 103 7.34993 102 d. 2.001063.00107 Perform the following mathematical operations, and express the result to the correct number of significant figures. a. 2.5263.1+0.4700.623+80.7050.4326 b. (6.404 2.91)/(18.7 - 17.1) c. 6.071 105 - 8.2 106 - 0.521 104 d. (3.8 1012 + 4.0 1013)/(4 1012 + 6.3 10l3) e. 9.5+4.1+2.8+3.1754 (Assume that this operation is taking the average of four numbers. Thus 4 in the denominator is exact.) f. 8.9258.9058.925100 (This type of calculation is done many times in calculating a percentage error. Assume that this example is such a calculation; thus 100 can be considered to be an exact number.)Perform the following mathematical operations, and express the result to the correct number of significant figures. a. 6.022 X 10-23 1.05 x 102 b. 6.626210342.9981082.54109 c. 1.285 102 + 1.24 103 + 1.879 101 d. (1.00866-1.00728)6.022051023 e. 9.8751029.7951029.875102100(100isexact) f. 9.42102+8.234102+1.6251033(3isexact)Perform each of the following conversions. a. 8.43 cm to millimeters b. 2.41 102 cm to meters c. 294.5 nm to centimeters d. 1.445 104 m to kilometers e. 235.3 m to millimeters f. 903.3 nm to micrometers a. How many kilograms are in 1 teragram? b. How many nanometers are in 6.50 x 102 terameters? c. How many kilograms are in 25 femtograms? d. How many liters are in 8.0 cubic decimeters? e. How many microliters are in 1 milliliter? f. How many picograms are in 1 microgram?Perform the following unit conversions. a. Congratulations! You and your spouse are the proud parents of a new baby, born while you are studying in a country that uses the metric system. The nurse has informed you that the baby weighs 3.91 kg and measures 51.4 cm. Convert your babys weight to pounds and ounces and her length to inches (rounded to the nearest quarter inch). b. The circumference of the earth is 25,000 mi at the equator. What is the circumference in kilometers? in meters? c. A rectangular solid measures 1.0 m by 5.6 cm by 2.1 dm. Express its volume in cubic meters, liters, cubic inches, and cubic feet.Perform the following unit conversions. a. 908 oz to kilograms b. 12.8 L to gallons c. 125 mL to quarts d. 2.89 gal to milliliters e. 4.48 lb to grams f. 550 mL to quarts Use the following exact conversion factors to perform the stated calculations: 512 yd -= 1 rod 40 rods = 1 furlong 8 furlongs = 1 mile a. The Kentucky Derby race is 1.25 miles. How long is the race in rods, furlongs, meters, and kilometers? b. A marathon race is 26 miles, 385 yards. What is this distance in rods, furlongs, meters, and kilometers?Although the preferred SI unit of area is the square meter, land is often measured in the metric system in hectares (ha). One hectare is equal to 10,000 m2. In the English system, land is often measured in acres (1 acre = 160 rod2). Use the exact conversions and those given in Exercise 47 to calculate the following. a. 1 ha = __________ km2 b. The area of a 5.5-acre plot of land in hectares, square meters, and square kilometers c. A lot with dimensions 120 ft by 75 ft is to be sold for 6500. What is the price per acre? What is the price per hectare?Precious metals and gems are measured in troy weights in the English system: 24 grains 1 pennyweight (exact) 20 pennyweight = 1 troy ounce (exact) 12 troy ounces 1 troy pound (exact) 1 grain = 0.0648 g 1 carat = 0.200 g a. The most common English unit of mass is the pound avoirdupois. What is 1 troy pound in kilograms and in pounds? b. What is the mass of a troy ounce of gold in grams and in carats? c. The density of gold is 19.3 g/cm3. What is the volume of a troy pound of gold?Apothecaries (druggists) use the following set of measures in the English system: 20 grains ap = 1 scruple (exact) 3 scruples = 1 dram ap (exact) 8 dram ap = 1 oz ap (exact) 1 dram ap = 3.888 g a. Is an apothecary grain the same as a troy grain? (See Exercise 49.) b. 1 oz ap = ____________ oz troy. c. An aspirin tablet contains 5.00 102 mg of active ingredient. What mass in grains ap of active ingredient does it contain? What mass in scruples? d. What is the mass of 1 scruple in grams?For a pharmacist dispensing pills or capsules, it is often easier to weigh the medication to be dispensed than to count the individual pills. If a single antibiotic capsule weighs 0.65 g, and a pharmacist weighs out 15.6 g of capsules, how many capsules have been dispensed?A children's pain relief elixir contains 80. mg acetaminophen per 0.50 teaspoon. The dosage recommended for a child who weighs between 24 and 35 lb is 1.5 teaspoons. What is the range of acetaminophen dosages, expressed in mg acetaminophen/kg body weight, for children who weigh between 24 and 35 lb?Science fiction often uses nautical analogies to describe space travel. If the starship U.S.S. Enterprise is traveling at warp factor 1.71, what is its speed in knots and in miles per hour'? (Warp 1.71 = 5.00 times the speed of light; speed of light = 3.00 108 m/s; 1 knot = 2030 yd/h.)The world record for the hundred meter dash is 9.58 s. What is the corresponding average speed in units of m/s, km/h, ft/s, and mi/h? At this speed, how long would it take to run 1.00 102 yards?You are driving 65 mi/h and take your eyes off the road for just a second. What distance (in feet) do you travel in this time?You pass a road sign saying New York 112 km. If you drive at a constant speed of 65 mi/h, how long should it take you to reach New York? If your car gets 28 miles to the gallon, how many liters of gasoline are necessary to travel 112 km?The dosage for an antibiotic is prescribed at 8.0 mg per kilo-gram of body weight, taken twice daily for two weeks. What total mass of antibiotic will be taken by a 180-lb person for the two-week period?In recent years, there has been a large push for an increase in the use of renewable resources to produce the energy we need to power our vehicles. One of the newer fuels that has become more widely available is E85, a mixture of 85% ethanol and 15% gasoline. Despite being more environmentally friendly, one of the potential drawbacks of E85 fuel is that it produces less energy titan conventional gasoline. Assume a car gets 28.0 mi/gal using gasoline at 3.50/gal and 22.5 mi/gal using E85 at 2.85/gal. How much will it cost to drive 500. miles using each fuel?59E Carbon monoxide (CO) detectors sound an alarm when peak levels of carbon monoxide reach 100 parts per million (ppm). This level roughly corresponds to a composition of air that contains 400,000 g carbon monoxide per cubic meter of air (400,000 g/m3). Assuming the dimensions of a room are 18 ft 12 ft 8 ft, estimate the mass of carbon monoxide in the room that would register 100 ppm on a carbon monoxide detector.Convert the following Fahrenheit temperatures to the Celsius and Kelvin scales. a. 459F, an extremely low temperature b. 40,F, the answer to a trivia question c. 68F, room temperature d. 7 107 F, temperature required to initiate fusion reactions in the sun A thermometer gives a reading of 96.1F 0.2F. What is the temperature in C? What is the uncertainty?Convert the following Celsius temperatures to Kelvin and to Fahrenheit degrees. a. the temperature of someone with a fever, 39.2C b. a cold wintery day, 25C c. the lowest possible temperature, 273C d. the melting-point temperature of sodium chloride, 801C Convert the following Kelvin temperatures to Celsius and Fahrenheit degrees. a. the temperature that registers the same value on both the Fahrenheit and Celsius scales, 233 K b. the boiling point of helium, 4 K c. the temperature at which many chemical quantities are determined, 298 K d. the melting point of tungsten, 3680 K At what temperature is the temperature in degrees Fahrenheit equal to twice the temperature in degrees Celsius?The average daytime temperatures on the earth and Jupiter are 72F and 313 K, respectively. Calculate the difference in temperature, in C, between these two planets.Use the figure below to answer the following questions. a. Derive the relationship between C and X. b. If the temperature outside is 22.0C, what is the temperature in units of X? c. Convert 58.0X to units of C, K, and F.Ethylene glycol is the main component in automobile anti-freeze. To monitor the temperature of an auto cooling system, you intend to use a meter that reads from 0 to 100. You devise a new temperature scale based on the approximate melting and boiling points of a typical antifreeze solution (45C and 115C). You wish these points to correspond to 0A and 100A, respectively. a. Derive an expression for converting between A and C. b. Derive an expression for converting between F and A. c. At what temperature would your thermometer and a Celsius thermometer give the same numerical reading? d. Your thermometer reads 86A. What is the temperature in C and in F? e. What is a temperature of 45C in A?A material will float on the surface of a liquid if the material has a density less than that of the liquid. Given that the density of water is approximately 1.0 g/mL, will a block of material having a volume of 1.2 104 in3 and weighing 350 lb float or sink when placed in a reservoir of water?One metal object is a cube with edges of 3.00 cm and a mass of 140.4 g. A second metal object is a sphere with a radius of 1.42 cm and a mass of 61.6 g. Are these objects made of the same or different metals? Assume the calculated densities are accurate to 1.00%.A star is estimated to have a mass of 2 1036 kg. Assuming it to be a sphere of average radius 7.0 105 km, calculate the average density of the star in units of grams per cubic centimeter.A rectangular block has dimensions 2.9 cm 3.5 cm 10.0 cm. The mass of the block is 615.0 g. What are the volume and density of the block?Diamonds are measured in carats, and 1 carat = 0.200 g. The density of diamond is 3.51 g/cm3. a. What is the volume of a 5.0-carat diamond? b. What is the mass in carats of a diamond measuring 2.8 mL?At room temperature the element bromine, Br2, is a liquid with a density of 3.12 g/cm3. Calculate the mass of 125 mL of bromine. What volume does 85.0 g of bromine occupy?A sample containing 33.42 g of metal pellets is poured into a graduated cylinder initially containing 12.7 mL of water, causing the water level in the cylinder to rise to 21.6 mL. Calculate the density of the metal.The density of pure silver is 10.5 g/cm3 at 20C. If 5.25 g of pure silver pellets is added to a graduated cylinder containing 11.2 mL of water, to what volume level will the water in the cylinder rise?In e-ach of the following pairs, which has the greater mass? (See Table 1.5.) a. 1.0 kg of feathers or 1.0 kg of lead b. 1.0 mL of mercury or 1.0 mL of water c. 19.3 mL of water or 1.00 mL of gold d. 75 mL of copper or 1.0 L of benzene a. Calculate the mass of ethanol in 1.50 qt of ethanol. (See Table 1.5.) b. Calculate the mass of mercury in 3.5 in3 of mercury. (See Table 1.5.)In each of the following pairs, which has the greater volume? a. 1.0 kg of feathers or 1.0 kg of lead b. 100 g of gold or 100 g of water c. 1.0 L of copper or 1.0 L of mercury Using Table 1.5, calculate the volume of 25.0 g of each of the following substances at 1 atm. a. hydrogen gas b. water c. iron Chapter 5 discusses the properties of gases. One property unique to gases is that they contain mostly empty space. Explain using the results of your calculations.The density of osmium (the densest metal) is 22.57 g/cm3. If a 1.00-kg rectangular block of osmium has two dimensions of 4.00 cm 4.00 cm. calculate the third dimension of the block.A copper wire (density = 8.96 g/cm3) has a diameter of 0.25 mm. If a sample of this copper wire has a mass of 22 g, how long is the wire?Match each description below with the following microscopic pictures. More than one picture may fit each description. A picture may be used more than once or not used at all. a. a gaseous compound b. a mixture of two gaseous elements c. a solid element d. a mixture of a gaseous element and a gaseous compound Define the following terms: solid, liquid, gas, pure substance, element, compound, homogeneous mixture, heterogeneous mixture, solution, chemical change, physical change.What is the difference between homogeneous and heterogeneous matter? Classify each of the following as homogeneous or heterogeneous. a. a door b. the air you breathe c. a cup of coffee (black) d. the water you drink e. salsa f. your lab partner Classify the following mixtures as homogeneous or heterogeneous. a. potting soil b. white wine c. your sock drawer d. window glass e. granite Classify each of the following as a mixture or a pure substance. a. water b. blood c. the oceans d. iron e. brass f. uranium g. wine h. leather i. table salt Of the pure substances, which are elements and which are compounds?Suppose a teaspoon of magnesium filings and a teaspoon of powdered sulfur are placed together in a metal beaker. Would this constitute a mixture or a pure substance? Suppose the magnesium filings and sulfur are heated so that they react with each other, forming magnesium sulfide. Would this still be a mixture? Why or why not?If a piece of hard, white blackboard chalk is heated strongly in a flame, the mass of the piece of chalk will decrease, and eventually the chalk will crumble into a fine white dust. Does this change suggest that the chalk is composed of an element or a compound?During a very cold winter, the temperature may remain below freezing for extended periods. However, fallen snow can still disappear, even though it cannot melt. This is possible because a solid can vaporize directly, without passing through the liquid state. Is this process (sublimation) a physical or a chemical change?Classify the following as physical or chemical changes. a. Moth balls gradually vaporize in a closet. b. Hydrofluoric acid attacks glass and is used to etch calibration marks on glass laboratory utensils. c. A French chef making a sauce with brandy is able to boil off the alcohol from the brandy, leaving just the brandy flavoring. d. Chemistry majors sometimes get holes in the cotton jeans they wear to lab because of acid spills.The properties of a mixture are typically averages of the properties of its components. The properties of a compound may differ dramatically from the properties of the elements that combine to produce the compound. For each process described below, state whether the material being discussed is most likely a mixture or a compound, and state whether the process is a chemical change or a physical change. a. An orange liquid is distilled, resulting in the collection of a yellow liquid and a red solid. b. A colorless, crystalline solid is decomposed, yielding a pale yellow-green gas and a soft, shiny metal. c. A cup of tea becomes sweeter as sugar is added to it.Two spherical objects have the same mass. One floats on water; the other sinks. Which object has the greater diameter? Explain.A 194-g sample of caffeine (C8H10N4O2) contains 6.02 1023 molecules of caffeine. If a typical 10-hour energy drink contains 422 mg of caffeine, how many molecules of caffeine are present in the drink?Lipitor, a pharmaceutical drug that has been shown to lower bad cholesterol levels while raising good cholesterol levels in patients taking the drug, had over 3 billion in sales in 2015. Assuming one 2.5-g pill contains 4.0% of the active ingredient by mass, what mass in kg of active ingredient is present in one bottle of 100 pills?In Shakespeares Richard III, the First Murderer says: Take that, and that! [Stabs Clarence] If that is not enough, Ill drown you in a malmsey butt within! Given that 1 butt = 126 gal, in how many liters of malmsey (a foul brew similar to mead) was the unfortunate Clarence about to be drowned?97AE In the opening scenes of the movie Raiders of the Lost Ark, Indiana Jones tries to remove a gold idol from a booby-trapped pedestal. He replaces the idol with a bag of sand of approximately equal volume. (Density of gold = 19.32 g/cm3; density of sand 2 g/cm3.) a. Did he have a reasonable chance of not activating the mass-sensitive booby trap? b. In a later scene, he and an unscrupulous guide play catch with the idol. Assume that the volume of the idol is about 1.0 L. If it were solid gold, what mass would the idol have? Is playing catch with it plausible?99AE The active ingredient of aspirin tablets is acetylsalicylic acid, which, has a density of 1.4 g/cm3. In a lab class, a student used paper chromatography to isolate another common ingredient of headache remedies. The isolated sample had a mass of 0.384 g and a volume of 0.32 cm3. Given the data in the following table, what was the other ingredient in the headache remedy? Density Values for Potential Headache Remedies Compound Density (g/cm3) White table sugar 0.70 Caffeine 1.2 Acetylsalicylic acid 1.4 Sodium chloride 2.2 This year, like many past years, you begin to feel very sleepy alter eating a large helping of Thanksgiving turkey. Some people attribute this sleepiness to the presence of the amino acid tryptophan in turkey. Tryptophan can be used by the body to produce serotonin, which can calm the brains activity and help to bring on sleep. a. What mass in grams of tryptophan is in a 0.25-lb serving of turkey? (Assume tryptophan accounts for 1.0% of the turkey mass.) b. What mass in grams of tryptophan is in 0.25 quart of milk? (Assume tryptophan accounts for 2.0% of milk by mass and that the density of milk is 1.04 kg/L.)Which of the following are chemical changes? Which are physical changes? a. the cutting of food b. interaction of food with saliva and digestive enzymes c. proteins being broken down into amino acids d. complex sugars being broken down into simple sugars e. making maple syrup by heating maple sap to remove water through evaporation f. DNA unwinding A person with high cholesterol has 250 mg of cholesterol per 100.0 mL of blood. If the total blood volume of the person is 5.4 L, what is the total mass (in grams) of cholesterol present in the persons blood?104AE A column of liquid is found to expand linearly on heating. Assume the column rises 5.25 cm for a 10.0F rise in temperature. If the initial temperature of the liquid is 98.6F, what will the final temperature be in C if the liquid has expanded by 18.5 cm?A 25.00-g sample of a solid is placed in a graduated cylinder, and then the cylinder is filled to the 50.0-mL mark with benzene. The mass of benzene and solid together is 58.80 g. Assuming that the solid is insoluble in benzene and that the density of benzene is 0.880 g/cm3, calculate the density of the solid.For each of the following, decide which block is more dense; the orange block, the blue block, or it cannot be determined. Explain your answers.According to the Official Rules of Baseball, a baseball must have a circumference not more than 9.25 in or less than 9.00 in and a mass not more than 5.25 oz or less than 5.00 oz. What range of densities can a baseball be expected to have? Express this range as a single number with an accompanying uncertainty limit.The density of an irregularly shaped object was determined as follows. The mass of the object was found to be 28.90 g 0.03 g. A graduated cylinder was partially filled with water. The reading of the level of the water was 6.4 cm3 0.1 cm3. The object was dropped in the cylinder, and the level of the water rose to 9.8 cm3 0.1 cm3. What is the density of the object with appropriate error limits? (See Appendix 1.5.)The chemist in Example 1.14 did some further experiments. She found that the pipet used to measure the volume of the liquid is accurate to 0.03 cm3. The mass measurement is accurate to 0.002 g. Are these measurements sufficiently precise for the chemist to distinguish between isopropyl alcohol and ethanol?The longest river in the world is the Nile River with a length of 4145 mi. How long is the Nile in cable lengths, meters, and nautical miles? Use these exact conversions to help solve the problem: 6 ft = 1 fathom 100 fathoms = 1 cable length 10 cable lengths = 1 nautical mile 3 nautical miles = 1 league Secretariat is known as the horse with the fastest run in the Kentucky Derby. If Secretariats record 1.25-mi run lasted 1 minute 59.2 seconds, what was his average speed in m/s?The hottest temperature recorded in the United States is 134F in Greenland Ranch, CA. The melting point of phosphorus is 44C. At this temperature, would phosphorus be a liquid or a solid?114CWP Which of the following statements is(are) true? a. A spoonful of sugar is a mixture. b. Only elements are pure substances. c. Air is a mixture of gases. d. Gasoline is a pure substance. e. Compounds can be broken down only by chemical means.Which of the following describes a chemical property? a. The density of iron is 7.87 g/cm3. b. A platinum wire glows red when heated. c. An iron bar rusts. d. Aluminum is a silver-colored metal.A rule of thumb in designing experiments is to avoid using a result that is the small difference between two large measured quantities. In terms of uncertainties in measurement, why is this good advice?Draw a picture showing the markings (graduations) on glassware that would allow you to make each of the following volume measurements of water, and explain your answers (the numbers given are as precise as possible). a. 128.7 mL b. 18mL c. 23.45 mL If you made these measurements for three samples of water and then poured all of the water together in one container, what total volume of water should you report? Support your answer.Many times errors are expressed in terms of percentage. The percent error is die absolute value of the difference of the true value and the experimental value, divided by the true value, and multiplied by 100. Percenterror=truevalue-experimentalvaluetruevalue100 Calculate the percent error for the following measurements. a. The density of an aluminum block determined in an experiment was 2.64 g/cm3. (True value 2.70 g/cm3.) b. The experimental determination of iron in iron ore was 16.48%. (True value 16.12%.) c. A balance measured the mass of a 1.000-g standard as 0.9981 g.A person weighed 15 pennies on a balance and recorded the following masses: 3.112 g 3.109 g 3.059 g 2.467 g 3.079 g 2.518 g 3.129 g 2.545 g 3.050 g 3.053 g 3.054 g 3.072 g 3.081 g 3.131 g 3.064 g Curious about the results, he looked at the dates on each penny. Two of the light pennies were minted in 1983 and one in 1982. The dates on the 12 heavier pennies ranged from 1970 to 1982. Two of the 12 heavier pennies were minted in 1982. a. Do you think the Bureau of the Mint changed the way it made pennies? Explain. b. The person calculated the average mass of the 12 heavy pennies. He expressed this average as 3.0828 g 0.0482 g. What is wrong with the numbers in this result, and how should the value be expressed?On October 21, 1982, the Bureau of the Mint changed the composition of pennies (see Exercise 120). Instead of an alloy of 95% Cu and 5% Zn by mass, a core of 99.2% Zn and 0.8% Cu with a thin shell of copper was adopted. The overall composition of the new penny was 97.6% Zn and 2.4% Cu by mass. Does this account for the difference in mass among die pennies in Exercise 120? Assume the volume of the individual metals that make up each penny can be added together to give the overall volume of the penny, and assume each penny is the same size. (Density of Cu = 8.96 g/cm3; density of Zn = 7.14 g/cm3).As part of a science project, you study traffic patterns in your city at an intersection in the middle of downtown. You set up a device that counts the ears passing through this intersection for a 24-hr period during a weekday. The graph of hourly traffic looks like this. a. At what time(s) does the highest number of cars pass through die intersection? b. At what time(s) does the lowest number of cars pass through die intersection? c. Briefly describe the trend in numbers of cars over the course of die day. d. Provide a hypothesis explaining the trend in numbers of cars over the course of the day. e. Provide a possible experiment that could test your hypothesis.Sterling silver is a solid solution of silver and copper. If a piece of a sterling silver necklace has a mass of 105.0 g and a volume of 10.12 mL, calculate the mass percent of copper in the piece of necklace. Assume that the volume of silver present plus the volume of copper present equals the total volume. Refer to Table 1.5. Masspercentofcopper=massofcoppertotalmass100 Make molecular-level (microscopic) drawings for each of the following. a. Show the differences between a gaseous mixture that is a homogeneous mixture of two different compounds, and a gaseous mixture that is a homogeneous mixture of a compound and an element. b. Show the differences among a gaseous element, a liquid element, and a solid element.Confronted with the box shown in the diagram, you wish to discover something about its internal workings. You have no tools and cannot open the box. You pull on rope B, and it moves rather freely. When you pull on rope A, rope C appears to be pulled slightly into the box. When you pull on rope C, rope A almost disappears into the box. a. Based on these observations, construct a model for the interior mechanism of the box. b. What further experiments could you do to refine your model?Use Daltons atomic theory to account for each of the following. a. the law of conservation of mass b. the law of definite proportion c. the law of multiple proportions What evidence led to the conclusion that cathode rays had a negative charge?What discoveries were made by J. J. Thomson, Henri Becquerel, and Lord Rutherford? How did Daltons model of the atom have to be modified to account for these discoveries?Consider Ernest Rutherfords -particle bombardment experiment illustrated in Fig. 2.12. How did the results of this experiment lead Rutherford away from the plum pudding model of the atom to propose the nuclear model of the atom?Do the proton and the neutron have exactly the same mass? How do the masses of the proton and neutron compare to the mass of the electron? Which particles make the greatest contribution to the mass of an atom? Which particles make the greatest contribution to the chemical properties of an atom?What is the distinction between atomic number and mass number? Between mass number and atomic mass?Distinguish between the terms family and period in connection with the periodic table. For which of these terms is the term group also used?The compounds AlCl3, CrCl3, and ICl3 have similar formulas, yet each follows a different set of rules to name it. Name these compounds, and then compare and contrast the nomenclature rules used in each case.9RQ How would you name HBrO4, KIO3, NaBrO2, and HIO? Refer to Table 2.5 and the acid nomenclature discussion in the text.Which of the following is true about an individual atom? Explain. a. An individual atom should be considered to be a solid. b.An individual atom should be considered to be a liquid. c. An individual atom should be considered to be a gas. d. The state of the atom depends on which element it is. e. An individual atom cannot be considered to be a solid, liquid, or gas. Justify your choice, and for choices you did not pick, explain what is wrong with them.How would you go about finding the number of chalk molecules it takes to write your name on the board? Provide an explanation of all you would need to do and a sample calculation.These questions concern the work of J. J. Thomson. a. From Thomsons work, which particles do you think he would feel are most important for the formation of compounds (chemical changes) and why? b. Of the remaining two subatomic particles, which do you place second in importance for forming compounds and why? c. Propose three models that explain Thomsons findings and evaluate them. To be complete you should include Thomsons findings.4ALQ You have a chemical in a sealed glass container filled with air. The setup is sitting on a balance as shown below. The chemical is ignited by means of a magnifying glass focusing sunlight on the reactant. After the chemical has completely burned, which of the following is true? Explain your answer. a. The balance will read less than 250.0 g. b. The balance will read 250.0 g. c. The balance will read greater than 250.0 g. d. Cannot be determined without knowing the identity of the chemical.The formula of water is If-O. Which of the following is indicated by this formula? Explain your answer. a. The mass of hydrogen is twice that of oxygen in each molecule. b. There are two hydrogen atoms and one oxygen atom per water molecule. c. The mass of oxygen is twice that of hydrogen in each molecule. d. There are two oxygen atoms and one hydrogen atom per water molecule.You may have noticed that when water boils, you can see bubbles that rise to die surface of the water. Which of die following is inside these bubbles? Explain. a. air b. hydrogen and oxygen gas c. oxygen gas d. water vapor e. carbon dioxide gas One of the best indications of a useful theory is that it raises more questions for further experimentation than it originally answered. Does this apply to Daltons atomic theory? Give examples.9ALQ Label each of the following as an atomic element, a molecular element, or a compound.Why is the term sodium chloride molecule incorrect whereas the term carbon dioxide molecule is correct?12ALQ Label each of the following as an atomic element, a molecular element, or a compound.14ALQ 15ALQ 16ALQ Which of tire following explain how an ion is formed'? Explain your answer. a. adding or subtracting protons to/from an atom b. adding or subtracting neutrons to/from an atom c. adding or subtracting electrons to/from an atom What refinements had to be made in Daltons atomic theory to account for Gay-Lussacs results on the combining volumes of gases?When hydrogen is burned in oxygen to form water, the composition of water formed does not depend on the amount of oxygen reacted. Interpret this in terms of the law of definite proportion.The two most reactive families of elements are the halogens and the alkali metals. How do they differ in their reactivities?Explain the law of conservation of mass, the law of definite proportion, and the law of multiple proportions.Section 2.3 describes the postulates of Daltons atomic theory. With some modifications, these postulates hold up very well regarding how we view elements, compounds, and chemical reactions today. Answer the following questions concerning Daltons atomic theory and the modifications made today. a. The atom can be broken down into smaller parts. What are the smaller parts? b. How are atoms of hydrogen identical to each other, and how can they be different from each other? c. How are atoms of hydrogen different from atoms of helium? How can H atoms be similar to He atoms? d. How is water different from hydrogen peroxide (H2O2) even though both compounds are composed of only hydrogen and oxygen? e. What happens in a chemical reaction, and why is mass conserved in a chemical reaction?The contributions of J. J. Thomson and Ernest Rutherford led the way to todays understanding of the structure of the atom. What were their contributions?24Q The number of protons in an atom determines the identity of the atom. What does the number and arrangement of the electrons in an atom determine? What does the number of neutrons in an atom determine?If the volume of a proton were similar to the volume of an electron, how will the densities of these two particles compare to each other?27Q List some characteristic properties that distinguish die metallic elements from the nonmetallic elements.Consider the elements of Group 4A (the carbon family): C, Si, Ge, Sn, and Pb. What is the trend in metallic character as one goes down this group? What is the trend in metallic character going from left to right across a period in the periodic table?Chlorine has two natural isotopes: 1737Cl and 1735Cl. Hydrogen reacts with chlorine to form the compound HCl. Would a given amount of hydrogen react with different masses of the two chlorine isotopes? Does this conflict with the law of definite proportion? Why or why not?Before an electrocardiogram (ECG) is recorded for a cardiac patient, the ECG leads are usually coated with a moist paste containing sodium chloride. Why is sodium chloride applied to the leads?Distinguish between the following terms. a. molecule versus ion b. covalent bonding versus ionic bonding c. molecule versus compound d. anion versus cation Label the type of bonding for each of the following.The vitamin niacin (nicotinic acid. C6H5NO2) can be isolated from a variety of natural sources such as liver, yeast, milk, and whole grain. It also can be synthesized from commercially available materials. From a nutritional point of view, which source of nicotinic acid is best for use in a multivitamin tablet? Why?35Q 36Q When mixtures of gaseous H2 and gaseous Cl2 react, a product forms that has the same properties regardless of the relative amounts of H2 and Cl2 used. a. How is this result interpreted in terms of the law of definite proportion? b. When a volume of H2 reacts with an equal volume of Cl2 at the same temperature and pressure, what volume of product having the formula HCl is formed?Observations of the reaction between nitrogen gas and hydrogen gas show us that 1 volume of nitrogen reacts with 3 volumes of hydrogen to make 2 volumes of gaseous product, as shown below: Determine the formula of the product and justify your answer.A sample of chloroform is found to contain 12.0 g of carbon, 106.4 g of chlorine, and 1.01 g of hydrogen. If a second sample of chloroform is found to contain 30.0 g of carbon, what is the total mass of chloroform in the second sample?A sample of H2SO4 contains 2.02 g of hydrogen, 32.07 g of sulfur, and 64.00 g of oxygen. How many grams of sulfur and grams of oxygen are present in a second sample of H2SO4 containing 7.27 g of hydrogen?Consider 80.0-g samples of two different compounds consisting of only carbon and oxygen. One of the compounds consists of 21.8 g of carbon, and the other has 34.3 g of carbon. Determine the ratio in whole numbers of the masses of carbon that combine with 1.00 g of oxygen between the two compounds.Several compounds containing sulfur and fluorine are known. Three of them have the following compositions: i. 1.188 g of F for every 1.000 g of S ii. 2.375 g of F for every 1.000 g of S iii. 3.563 g of F for every 1.000 g of S How do these data illustrate the law of multiple proportions?The three most stable oxides of carbon ire carbon monoxide (CO), carbon dioxide (CO2), and carbon suboxide (C3O2). The molecules can be represented as Explain how these molecules illustrate the law of multiple proportions.Two elements. R and Q, combine to form two binary compounds. In the first compound, 14.0 g of R combines with 3.00 g of Q. In the second compound, 7.00 g of R combines with 4.50 g of Q. Show that these data are in accord with the law of multiple proportions. If the formula of the second compound is RQ, what is the formula of the first compound?In Section 1.1 of the text, the concept of a chemical reaction was introduced with the example of the decomposition of water, represented as follows: Use ideas from Dalton's atomic theory to explain how the above representation illustrates the law of conservation of mass.In a combustion reaction, 46.0 g of ethanol reacts with 96.0 g of oxygen to produce water and carbon dioxide. If 54.0 g of water is produced, what mass of carbon dioxide is produced?Early tables of atomic weights (masses) were generated by measuring the mass of a substance that reacts with 1.00 g of oxygen. Given the following data and taking the atomic mass of hydrogen as 1.00, generate a table of relative atomic masses for oxygen, sodium, and magnesium. Element Mass That Combines with 1.00g Oxygen Assumed Formula Hydrogen 0.126 g HO Sodium 2.875 g NaO Magnesium 1.500 g MgO How do your values compare with those in the periodic table? How do you account for any differences?Indium oxide contains 4.784 g of indium for every 1.000 g of oxygen. In 1869, when Mendeleev first presented his version of the periodic table, he proposed the formula In2O3 for indium oxide. Before that time it was thought that the formula was InO. What values for the atomic mass of indium are obtained using these two formulas? Assume that oxygen has an atomic mass of 16.00.49E If you wanted to make an accurate scale model of the hydrogen atom and decided that the nucleus would have a diameter of 1 mm, what would be the diameter of the entire model?In an experiment it was found that the total charge on an oil drop was 5.93 1018 C. How many negative charges does the drop contain?A chemist in a galaxy tar, far away performed the Millikan oil drop experiment and got the following results for the charges on various drops. Use these data to calculate the charge of the electron in zirkombs. 2.56 1012 zirkombs 7.68 1012 zirkombs 3.84 1012 zirkombs 6.40 1013 zirkombs What are the symbols of the following nonmetals: fluorine, chlorine, bromine, sulfur, oxygen, phosphorus?55E In the periodic table, how many elements are found in each of the following? a. the hologen family b. the alkali family c. the lanthanide series d. transition metals a. Classify the following elements as metals or nonmetals: Mg Si Rn Ti Ge Rn Au B Am Bi At Br b. The distinction between metals and nonmetals is really not a clear one. Some elements, called metalloids, are intermediate in their properties. Which of these elements would you reclassify as metalloids? What other elements in the periodic table would you expect to be metalloids?a. List the noble gas elements. Which of the noble gases has only radioactive isotopes? (This situation is indicated on most periodic tables by parentheses around the mass of the element. See inside front cover.) b. Which lanthanide element has only radioactive isotopes?For each of the following sets of elements, label each as either noble gases, halogens, alkali metals, alkaline earth metals, or transition metals. a. Ti, Fe, Ag b. Mg, Sr, Ba c. Li, K., Rb d. Ne, Kr, Xe e. F, Br, I 60E 61E Write the atomic symbol (ZAX) for each of the isotopes described below. a. number of protons = 27, number of neutrons = 31 b. the isotope of boron with mass number 10 c. Z = 12, A = 23 d. atomic number 53, number of neutrons = 79 e. Z = 20, number of neutrons = 27 f. number of protons = 29, mass number 65 Write the symbol of each atom using the ZAX format. a. b. c.For carbon-14 and carbon-12, how many protons and neutrons are in each nucleus? Assuming neutral atoms, how many electrons are present in an atom of carbon-14 and in an atom of carbon-12?How many protons and neutrons are in the nucleus of each of the following atoms? In a neutral atom of each element, how many electrons are present? a. 79Br b. 81Br c. 239Pu d. 133Cs e. 3H f. 56Fe 66E For each of the following ions, indicate the number of protons and electrons the ion contains. a. Ba2+ b. Zn2+ c. N3 d. Rb e. Co3 f. Te2 g. Br How many protons, neutrons, and electrons are in each of the following atoms or ions? a. 1224Mg b. 1224Mg2+ c. 2799Co2+ d. 2799Co3+ e. 2799Co f. 3479Se g. 3479Se2 h. 2863Ni i. 2899Ni2+69E What is the symbol of an ion with 16 protons, 18 neutrons, and 18 electrons? What is the symbol for an ion that has 16 protons, 16 neutrons, and 18 electrons?Complete the following table: Symbol Number of Protons in Nucleus Number of Neutrons in Nucleus Number of Electrons Net Charge 92238U 20 20 2+ 23 28 20 3989Y 35 44 36 15 16 3 Complete the following table: Symbol Number of Protons in Nucleus Number of Neutrons in Nucleus Number of Electrons Net Charge 2653Fe2+ 26 33 3+ 85 125 86 13 14 10 76 54 2 Would you expect each of the following atoms to gain or lose electrons when forming ions? What ion is the most likely in each case? a. Ra b. In c. P d. Te e. Br f. Rb 74E Name the compounds in parts ad and write the formulas for the compounds in parts eh. a. NaBr b. Rb2O c. CaS d. AlI3 e. strontium fluoride f. aluminum selenide g. potassium nitride h. magnesium phosphide Name the compounds in parts a-d and write the formulas for the compounds in parts eh. a. Hg2O b. FeBr3 c. CoS d. TiCl4 e. tin(II) nitride f. cobalt(III) iodide g. mercury(II) oxide h. chromium(VI) sulfide 77E 78E 79E 80E 81E 82E 83E 84E 85E 86E 87E Write the formula for each of the following compounds a. chromium(VI) oxide b. disulfur dichloride c. nickel(II) fluoride d. potassium hydrogen phosphate e. aluminum nitride f. ammonia g. manganese(IV) sulfide h. sodium dichromate i. ammonium sulfite j. carbon tetraiodide 89E Write the formula for each of the following compounds: a. ammonium hydrogen phosphate b. mercury (I) sulfide c. silicon dioxide d. sodium sulfite e. aluminum hydrogen sulfate f. nitrogen trichloride g. hydiobromic acid h. bromous acid i. perbromic acid j. potassium hydrogen sulfide k. calcium iodide l. cesium perchlorate 91E Each of the following compounds is incorrectly named is wrong with each name, and what is the correct name each compound? a. FeCl3 iron chloride b. NO2, nitrogen(IV) oxide c. CaO, calcium(II) monoxide d. Al2S3, dialuminum trisulfide e. Mg(C2,H3O2)2, manganese diacetate f. FePO4, iron(II) phosphide g. P2S5, phosphorus sulfide h. Na2O2, sodium oxide i. HNO3 nitrate acid j. H2S, sulfuric acid Insulin is a complex protein molecule produced by the pancreas in all vertebrates. It is a hormone that regulates carbohydrate metabolism. Inability to produce insulin results in diabetes mellitus. Diabetes is treated by injections of insulin. Given the law of definite proportion, would you expect there to be any differences in chemical activity between human insulin extracted from pancreatic tissue and human insulin produced by genetically engineered bacteria? Why or why not?Carbohydrates, a class of compounds containing the elements carbon, hydrogen, and oxygen, were originally thought to contain one water (H2O) molecule for each carbon atom present. The carbohydrate glucose contains six carbon atoms. Write a general formula showing the relative numbers of each type of atom present in glucose.95AE What are the symbols for the following nonmetal elements that are most often present in compounds studied in organic chemistry: carbon, hydrogen, oxygen, nitrogen, phosphorus, sulfur? Predict a stable isotope for each of these elements.Four Fe2+ ions are key components of hemoglobin, the protein that transports oxygen in the blood. Assuming that these ions are 53Fe2+, how many protons and neutrons are present in each nucleus, and how many electrons are present in each ion?Which of the following statements is(are) true? For the false statements, correct them. a. All particles in the nucleus of an atom are charged. b. The atom is best described as a uniform sphere of matter in which electrons are embedded. c. The mass of the nucleus is only a very small fraction of the mass of the entire atom. d. The volume of the nucleus is only a very small fraction of the total volume of the atom. e. The number of neutrons in a neutral atom must equal the number of electrons.The isotope of an unknown element, X, has a mass number of 79. The most stable ion of the isotope has 36 electrons and forms a binary compound with sodium, having a formula of Na2X. Which of the following statements is(are) true? For the false statements, correct them. a. The binary compound formed between X and fluorine will be a covalent compound. b. The isotope of X contains 38 protons. c. The isotope of X contains 41 neutrons. d. The identity of X is strontium, Sr.100AE 101AE Identify each of the following elements: a. a member of the same family as oxygen whose most stable ion contains 54 electrons b. a member of the alkali metal family whose most stable ion contains 36 electrons c. a noble gas with 18 protons in the nucleus d. a halogen with 85 protons and 85 electrons 103AE 104AE 105AE 106AE 107AE 108AE Consider 100.0-g samples of two different compounds consisting only of carbon and oxygen. One compound contains 27.2 g of carbon, and the other has 42.9 g of carbon. How can these data support die law of multiple proportions if 42.9 is not a multiple of 27.2? Show that these data support the law of multiple proportions.Give the systematic name for the following compounds that are found in everyday life: a. H2S (rotten egg smell) b. SO2 (smell of burnt matches) c. SFs (aerosol can propellant) d. Na2SO3 (dried fruit preservative)111CWP 112CWP Complete the following table. Atom/Ion Protons Neutrons Electrons S50120n M1225g2+ F2656e2+ S3479e C1735l C2963u Which of the following is{are) correct? a. 40Ca2 contains 20 protons and 18 electrons. b. Rutherford created the cathode-ray tube and was the founder of the charge-to-mass ratio of an electron. c. An electron is heavier than a proton. d. The nucleus contains protons, neutrons, and electrons.115CWP 116CWP 117CWP 118CWP Reaction of 2.0 L of hydrogen gas with 1.0 L of oxygen gas yields 2.0 L of water vapor. All gases are at the same temperature and pressure. Show how these data support the idea that oxygen gas is a diatomic molecule. Must we consider hydrogen to be a diatomic molecule to explain these results?A combustion reaction involves the reaction of a substance with oxygen gas. The complete combustion of any hydrocarbon (binary compound of carbon and hydrogen) produces carbon dioxide and water as the only products. Octane is a hydrocarbon that is found in gasoline. Complete combustion of octane produces 8 L of carbon dioxide for every 9 L of water vapor (both measured at the same temperature and pressure). What is the ratio of carbon atoms to hydrogen atoms in a molecule of octane?A chemistry instructor makes the following claim: Consider that if the nucleus were the size of a grape, the electrons would be about 1 mile away on average. Is this claim reasonably accurate? Provide mathematical support.The early alchemists used to do an experiment in which water was boiled for several days in a sealed glass container. Eventually. some solid residue would appear in die bottom of the flask, which was interpreted to mean that some of the water in the flask had been converted into earth. When Lavoisier repeated this experiment, he found that the water weighed the same before and after heating, and the mass of die flask plus the solid residue equaled the original mass of the flask. Were the alchemists correct? Explain what really happened. (This experiment is described in the article by A. F. Scott in Scientific American, January 1984.)Consider the chemical reaction as depicted below. Label as much as you can using the terms atom, molecule, element, compound, ionic, gas, and solid.Each of the following statements is true, but Dalton might have had trouble explaining some of them with his atomic theory. Give explanations for the following statements. a. The space-filling models for ethyl alcohol and dimethyl ether are shown below. These two compounds have die same composition by mass (52% carbon, 13% hydrogen, and 35% oxygen), yet the two have different melting points, boiling points, and solubilities in water. b. Burning wood leaves an ash that is only a small fraction of the mass of the original wood. c. Atoms can be broken down into smaller particles. d. One sample of lithium hydride is 87.4% lithium by mass, while another sample of lithium hydride Ls 74.9% lithium by mass. However, the two samples have the same chemical properties.You have two distinct gaseous compounds made from element X and element Y. The mass percents are as follows: Compound I: 30.43% X, 69.57% Y Compound II: 63.64% X, 36.36% Y In their natural standard states, element X and element Y exist as gases. (Monatomic? Diatomic? Triatomic? That is for you to determine.) When you react gas X with gas Y to make the products, you get the following data (all at the same pressure and temperature): 1 volume gas X + 2 volumes gas Y 2 volumes compound I 2 volumes gas X + 1 volume gas Y 2 volumes compound II Assume the simplest possible formulas for reactants and products in the chemical equations above. Then, determine the relative atomic masses of element X and element Y.A single molecule has a mass of 7.31 1023 g. Provide an example of a real molecule that can have this mass. Assume the elements that make up the molecule are made of light isotopes where the number of protons equals the number of neutrons in the nucleus of each element.You take three compounds, each consisting of two elements (X, Y. and/or Z), and decompose them to their respective elements. To determine the relative masses of X, Y. and Z. you collect and weigh the elements, obtaining the following data: Elements in Compound Masses of Elements 1. X and Y X = 0.4 g, Y = 4.2 g 2. Y and Z Y = 1.4 g, Z = 1.0 g 3. X and Y X = 2.0 g, Y = 7.0 g a. What are the assumptions needed to solve this problem? b. What are the relative masses of X, Y. and Z? c. What are the chemical formulas of the three compounds? d. If you decompose 21 g of compound XY, how much of each element is present?129IP 130IP Using the information in Table 2.1, answer the following questions. In an ion with an unknown charge, the total mass of all the electrons was determined to be 2.55 1026 g. while the total mass of its protons was 5.34 1023 g. What is the identity and charge of this ion? What is the symbol and mass number of a neutral atom whose total mass of its electrons is 3.92 1026 g, while its neutrons have a mass of 9.35 1023 g?1RQ Atomic masses are relative masses. What does this mean?The atomic mass of boron (B) is given in the periodic table as 10.81, yet no single atom of boron has a mass of 10.81 u. Explain.What three conversion factors and in what order would you use them to convert the mass of a compound into atoms of a particular element in that compoundfor example, from 1.00 g aspirin (C9H8O4) to number of hydrogen atoms in the 1.00-g sample?Fig. 5-5 illustrates a schematic diagram of a combustion device used to analyze organic compounds. Given that a certain amount of a compound containing carbon, hydrogen, and oxygen is combusted in this device, explain how the data relating to the mass of CO2 produced and the mass of H2O produced can be manipulated to determine the empirical formula.What is the difference between the empirical and molecular formula of a compound? Can they ever be the same? Explain.Consider the hypothetical reaction between A2 and AB pictured below. What is the balanced equation? lf 2.50 moles of A2 are reacted with excess AB, what amount (moles) of product will form? If the mass of AB is 30.0 u and the mass of A2 are 40.0 u, what is the mass of the product? If 15.0 g of AB is reacted, what mass of A2 is required to react with all of the AB, and what mass of product is formed?8RQ Consider the following mixture of SO2(g) and O2(g). If SO2(g) and O2(g) react to form SO3(g), draw a representation of the product mixture assuming the reaction goes to completion. What is the limiting reactant in the reaction? If 96.0 g of SO2 react with 32.0 g O2, what mass o f product will form?Why is the actual yield of a reaction often less than the theoretical yield?The following are actual student responses to the question: Why is it necessary to balance chemical equations? a. The chemicals will not react until you have added the correct mole ratios. b. The correct products will not be formed unless the right amount of reactants have been added. c. A certain number of products cam1ot be formed without a certain number of reactants. d. The balanced equation tells you how much reactant you need and allows you to predict how much product youll make. e. A mole-to-mole ratio must be established for the reaction to occur as written. Justify the best choice, and for choices you did not pick, explain what is wrong with them.What information do we get from a chemical formula? From a chemical equation?True or false? The atom with the largest subscript in a formula is die atom with the largest percent by mass in the compound. If true, explain why with an example. If false, explain why with an example. In either case, provide mathematical support You have a 20.0-g sample of silver metal. You are given 10.0 g of another metal and told that tills sample contains twice the number of atoms as the sample of silver metal. Is this possible?You are making cookies and are missing a key ingredienteggs. You have most of the other ingredients needed to make the cookies, except you have only 1.33 cups of butter and no eggs. You note that the recipe calls for two cups of butter and three eggs (plus the other ingredients) to make six dozen cookies. You call a friend and have him bring you some eggs. a. What number of eggs do you need? b. If you use all the butter (and get enough eggs), what number of cookies will you make? Unfortunately, your friend hangs up before you tell him how many eggs you need. When he arrives, he has a surprise for you to save time, he has broken them all in a bowl for you. You ask him how many he brought, and he replies. I cant remember. You weigh the eggs and find that they weigh 62.1 g. Assuming that an average egg weighs 34.21 g. a. What quantity of butter is needed to react with all the eggs? b. What number of cookies can you make? c. Which will you have left over, eggs or butter? d. What quantity is left over?Nitrogen gas (N2) and hydrogen gas (H2) react to form ammonia gas (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.For the preceding question, which of the following equations best represents the reaction? a. 6N2 + 6H2 4NH3+ 4N2 b. N2 + H2 NH3 c. N + 3H NH3 d. N2 + 3H2 2NH3 e. 2N2 + 6H2 4NH3 Justify your choice, and for choices you did not pick, explain what is wrong with them.You 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 determine the amount of product that will be produced? Explain.9ALQ Consider an iron bar on a balance as shown. As the iron bar rusts, which of the following is true? Explain your answer. a. The balance will read less than 75.0 g. b. The balance will read 75.0 g. c. The balance will read greater than 75.0 g. d. The balance will read greater than 75.0 g, but if the bar is removed, the rust is scraped off, and the bar replaced, the balance will read 75.0 g.You may have noticed that water sometimes drips from the exhaust of a car as it is running. Is this evidence that there is at least a small amount of water originally present in the gasoline? Explain.12ALQ What is true about the chemical properties of the product? a. The properties are more like chemical A. b. The properties are more like chemical B. c. The properties are an average of those of chemical A and chemical B. d. The properties are not necessarily like either chemical A or chemical B. e. The properties arc more like chemical A or more like chemical B, but more information is needed. Justify your choice, and for choices you did not pick, explain what is wrong with them.Is there a difference between a homogeneous mixture of hydrogen and oxygen in a 2:1 mole ratio and a sample of water vapor? Explain.Chlorine exists mainly as two isotopes, 37Cl and 33Cl. Which is more abundant? How do you know?The average mass of a carbon atom is 12.011. Assuming you could pick up one carbon atom, estimate the chance that you would randomly get one with a mass of 12.011. Support your answer.Can the subscripts in a chemical formula be fractions? Explain. Can the coefficients in a balanced chemical equation be fractions? Explain. Changing the subscripts of chemicals can balance the equations mathematically. Why is this unacceptable?Consider the equation 2A + B . A2B. If you mix 1.0 mole of A with 1.0 mole of B, what amount (moles) of A2B can be produced?According to the law of conservation of mass, mass cannot be gained or destroyed in a chemical reaction. Why cant you simply add the masses of two reactants to determine the total mass of product?

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