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All Textbook Solutions for Chemistry & Chemical Reactivity

Which of the following is a pure substance? (a) dry ice (solid CO2) (b) 9 K gold (c) dry air (d) blood Which of the following is not characteristic of a pure substance? (a) Has a uniform composition throughout (b) Has a fixed melting temperature (c) Can be separated into two other pure substances 1RC 2RC 1RC 2. Which of the following is NOT a compound? salt water potassium sugar alcohol Which of the following is NOT a physical property? (a) Liquid nitrogen boils at 196 C. (b) Sugar dissolves in water. (c) Gasoline burns in air. (d) Gold melts at 1064 C. (e) A copper compound is blue.2. A piece of a polypropylene rope (used for water skiing) floats on water, whereas a terephthalate polymer from a soda bottle sinks in water. What is the order of increasing density of these substances? water < polypropylene < soda bottle plastic polypropylene < water < soda bottle plastic polypropylene < soda bottle plastic < water soda bottle plastic < polypropylene < water soda bottle plastic < water < polypropylene Which of the following is an extensive property of mercury (see Figure 1.10)? (a) shiny surface (b) melts at 234.22 K (c) density = 13.6 g/cm3 (d) volume = 13.6 cm3 When camping in the mountains, you boil a pot of water on a campfire to make tea. Which of the following is a chemical change? (a) The water boils. (b) The campfire wood burns. (c) The tea dissolves in the hot water. (d) The pot melts from the heat of the fire.Much has been written about CO2.What is its name?2Q 3Q The spines of the sea urchin, corals, and coccolithophores all are built of the compound CaCO3. What elements are involved in this compound? Do you know its name?Which of the following has the highest thermal energy? (a) 1.0 g of ice at 0 (b) 1.0 g of liquid water at 25 C (c) 1.0 g of liquid water at 100 C (d) 1.0 g of water vapor at 100 C 2RC Give the name of each of the following elements: (a) C (b) K (c) CI (d) P (e) MG (f) Ni Give the name of each of the following elements: (a) Mn (b)Cu (c) Na (d) Br (e) Xe (f) Fe Give the symbol for each of the following elements: (a) barium (b) titanium (c) chromium (d) lead (e) arsenic (f) zinc Give the symbol for each of the following elements: (a) silver (b) aluminum (c) plutonium (d) tin (e) technetium (f) krypton In each of the following pairs, decide which is an element and which is a compound. (a) Na or NaCl (b) sugar or carbon (c) gold or gold chloride In each of the following pairs, decide which is an element and which is a compound. (a) Pt(NH3)2Cl2 or Pt (b) copper or copper(II) oxide (c) silicon or sand In each case, decide if the underlined property is a physical or chemical property. (a) The color of elemental bromine is orange-red. (b) Iron turns to rust in the presence of air and water. (c) Hydrogen can explode when ignited in air (Figure 1.16). (d) The density of titanium metal is 4.5 g/cm3. (e) Tin metal melts at 505 K. (f) Chlorophyll, a plant pigment, is green.In each case, decide if the change is a chemical or physical change. (a) A cup of household bleach changes the color of your favorite T-shirt from purple to pink. (b) Water vapor in your exhaled breath condenses in the air on a cold day. (c) Plants use carbon dioxide from the air to make sugar. (d) Butter melts when placed in the Sun.Which part of the description of a compound or element refers to its physical properties and which to its chemical properties? (a) The colorless liquid ethanol bums in air. (b) The shiny metal aluminum reacts readily with orange-red bromine Which part of the description of a compound or element refers to its physical properties and which to its chemical properties? (a) Calcium carbonate is a white solid with a density of 2.71 g/cm3. It reacts readily with an acid to produce gaseous carbon dioxide. (b) Gray, powdered zinc metal reacts with purple iodine to give a white compound The flashlight in the photo does not use batteries. Instead, you move a lever, which turns a geared mechanism and finally results in light from the bulb. What type of energy is used to move the lever? What type or types of energy are produced?A solar panel is pictured in the photo. When light shines on the panel, it generates an electric current that can be used to recharge the batteries in an electric car. What types of energy are involved in this setup?Determine which of the following represent potential energy and which represent kinetic energy. (a) thermal energy (b) gravitational energy (c) chemical energy (d) electrostatic energy 14PS 15GQ Iron pyrite (fool's gold, page 11) has a shiny golden metallic appearance. Crystals are often in the form of perfect cubes. A cube 0.40 cm on each side has a mass of 0.064 g. (a) Which of these observations are qualitative and which are quantitative? (b) Which of the observations are extensive and which are intensive? (c) What is the density of the sample of iron pyrite?Which observations below describe chemical properties? (a) Sugar is soluble in water. (b) Water boils at 100 C. (c) Ultraviolet light converts O3 (ozone) to O2 (oxygen). (d) Ice is less dense than water.Which observations below describe chemical properties? (a) Sodium metal reacts violently with water. (b) The combustion of octane (a compound in gasoline) gives CO2 and H2O. (c) Chlorine is a green gas. (d) Heat is required to melt ice.The mineral fluorite contains the elements calcium and fluorine and can have various colors, including blue, violet, green, and yellow. (a) What are the symbols of these elements? (b) How would you describe the shape of the fluorite crystals in the photo? What can this tell us about the arrangement of the particles (ions) inside the crystal?Azurite, a blue, crystalline mineral, is composed of copper, carbon, and oxygen. (a) What are the symbols of the three elements that combine to make the mineral azurite? (b) Based on the photo, describe some of the physical properties of the elements and the mineral. Are any the same? Are any properties different?You have a solution of NaCI dissolved in water. Describe a method by which these two compounds could be separated Small chips of iron are mixed with sand (see photo). Is this a homogeneous or heterogeneous mixture? Suggest a way to separate the iron from the sand.Identify the following as either physical changes or chemical changes. (a) Diy ice (solid CO2) sublimes (converts directly from solid to gaseous CO2). (b) Mercury's density decreases as the temperature increases. (c) Energy is given off as heat when natural gas (mostly methane, CH4) burns. (d) NaCI dissolves in water Identify the following as either physical changes or chemical changes. (a) The desalination of sea water (separation of pure water from dissolved salts). (b) The formation of SO2 (an air pollutant) when coal containingsulfur is burned. (c) Silver tarnishes. (d) Iron is heated to red heat In Figure 1.2 you see a piece of salt and a representation of its internal structure. Which is the macroscopic view and which is the particulate view? How are the macroscopic and particulate views related?In Figure 1.5 you see macroscopic and particulate views of the element bromine. Which are the macroscopic views and which are the particulate views? Describe how the particulate views explain properties of this element related to the state of matter.27GQ The following photo shows copper balls, immersed in water, floating on top of mercury. What are the liquids and solids in this photo? Which substance is most dense? Which is least dense?Categorize each of the following as an element, a compound, or a mixture. (a) sterling silver (b) carbonated mineral water (c) tungsten (d) aspirin Categorize each of the following as an element, a compound, or a mixture. (a) air (b) fluorite (c) brass (d) 18-carat gold Make a drawing, based on the kinetic-molecular theory and the ideas about atoms and molecules presented in this chapter, of the arrangement of particles in each of the cases listed here. For each case, draw 10 particles of each substance. It is acceptable for your diagram to be two dimensional. Represent each atom as a circle, and distinguish each different kind of atom by shading. (a) a sample of solid iron (which consists of iron atoms) (b) a sample of liquid water (which consists of H2O molecules) (c) a sample of water vapor Make a drawing, based on the kinetic-molecular theory and the ideas about atoms and molecules presented in this chapter, of the arrangement of particles in each of the cases listed here. For each case, draw 10 particles of each substance. It is acceptable for your diagram to be two dimensional. Represent each atom as a circle, and distinguish each different kind of atom by shading. (a) a homogeneous mixture of water vapor and helium gas (which consists of helium atoms) (b) a heterogeneous mixture consisting of liquid water and solid aluminum; show a region of the sample that includes both substances (c) a sample of brass (which is a homogeneous solid mixture of copper and zinc)Hexane (C6H14, density = 0.766 g/cm3), perfluoro-hexane (C6F14, density = 1.669 g/cm3), and water are immiscible liquids; that is, they do not dissolve in one another. You place 10 mL of each in a graduated cylinder, along with pieces of high-density polyethylene (HDPE, density = 0.97 g/cm3), polyvinyl chloride(PVC, density = 1.36 g/cm3), and Teflon (density = 2.3 g/cm3). None of these common plastics dissolves in these liquids. Describe what you expect to see.You have a sample of a white crystalline substance from your kitchen. You know that it is either salt or sugar. Although you could decide by taste, suggest another property that you could use to decide. (Hint: You may use the World Wide Web or a handbook of chemistry in the library to find some information.)You can figure out whether a solid floats or sinks if you know its density and the density of the liquid. In which of the liquids listed below will high-density polyethylene (HDPE) float? (HDPE, a common plastic, has a density of 0.97 g/cm3. It does not dissolve in any of these liquids.)You are given a sample of a silvery metal. What information could you use to prove the metal is silver?Milk in a glass bottle was placed in the freezing compartment of a refrigerator overnight. By morning a column of frozen milk emerged from the bottle. Explain this observation.Describe an experimental method that can be used to determine the density of an irregularly shapedpiece of metal Diabetes can alter the density of urine, so urine density can be used as a diagnostic tool. Diabetics can excrete too much sugar or excrete too much water. What do you predict will happen to the density of urine under each of these conditions? (Hint: Water containing dissolved sugar is more dense than pure water.)40GQ The following photo shows the element potassium reacting with water to from the element hydrogen, a gas, and a solution of the compound potassium hydroxide. (a) What states of matter are involved in the reaction? (b) Is the observed change chemical or physical? (c) What are the reactants in this reaction, and what are the produces? (d) What qualitative observations can be made concerning this reaction?42GQ Four balloons are each filled with a different gas, each having a different density: If the density of dry air is 1.12 g/L, which balloon or balloons float in air?44GQ The photo below shows elemental iodine dissolving in ethanol to give a solution. Is this a physical or chemical change?A few years ago a young chemist in Vienna, Austria, wanted to see just how permanent the gold was in his wedding band. The ring was 18-carat gold. (18-carat gold is 75% gold with the remainder copper and sliver) One week after his wedding day he took off the ring, cleaned it carefully, and weighed it. It had a mass of 5.58387 g. He weighed it weekly from then on,and after 1 year it had lost 6.15 mg just from normal wear and tear. He found that the activities that took the greatest toll on the gold were vacationing on a sandy beach and gardening. (a) What are the symbol of the elements that make up 18-carat gold? (b) The density of gold is 19.3 g/cm3. Use one of the periodic tables on the Internet (such as www.ptable.com) to find out if gold is the most dense of all of the known elements. If it is not gold, then what element is the most dense [considering only the elements from hydrogen (H) through uranium (U)]? (c) If a wedding band is 18-carat gold and has a mass of 5.58 g, what mass of gold is contained within the ring? (d) Assume there are 56 million married couples in the United States, and each person has an 18-carat gold ring. What mass of gold lost by all the wedding rings in the United States in 1 year (in units of grams) if each ring loses 6.15 mg of mass per year? Assuming gold is 1620 per troy ounce (where 1 troy ounce = 31.1 g), what is the lost gold worth?The distance between two carbon atoms in diamond (Figure 2) is 0.154 nm. What is this distance in picometers (pm)? In centimeters (cm)?1RC 2RC 3RC 4RC 5. A circulated U.S. quarter has a mass of 5.59 g. Express this mass in milligrams. 5.59 × 103 mg 5.59 mg 55.9 mg 559 mg 6RC 7RC Two students measured the freezing point of a sample of pure benzene. Student A used an ordinary laboratory thermometer calibrated in 0.1 ℃ units. Student B used a thermometer certified by NIST (National Institute of Standards and Technology) and calibrated in 0.01 °C units. Their results were as follows: Student A: 52 °C, 5.7 °C, 5.5 °C, 5.2 °C Student B: 5.48 °C, 5.52 °C, 5.50 °C, 5.54 °C Calculate the average value for A and B and, knowing the freezing point of benzene is 5.50 °C (and using kelvins for temperature), calculate the percent error for each student. Which student has the smaller error? 1RC Two students were assigned to determine the mass of a sample of an unknown liquid. Student A used an ordinary laboratory balance that could determine mass to ±0.01 g. Student B used an analytical balance that could measure mass to ±0.1 mg. Each made four measurements, giving the following results: Student A: 8.19 g, 8.22 g, 8.21 g, 8.25 g Student B: 8.2210 g, 8.2210 g, 8.2209 g, 8.2210 g 2. Which student is more precise? A B 1CYU 1RC 2RC 3. What is the sum of 10.26 g and 0.063 g? 10.323 g 10.32 g 10.3 g 10. g 4RC The density of gold is 19,320 kg/m3. What is this density in g/cm3?1. A lake has an area of 2.33 × 107 m2. What is this area in square kilometers? 23.3 km2 2.33 × 1010 km2 23.3 × 10−3 km2 2.33 × 104 km2 A particular paint has a density of 0.914 g/cm3. You need to cover a wall that is 7.6 m long and 2.74 m high with a paint layer 0.13 mm thick. What volume of paint (in liters) is required? What is the mass (in grams) of the paint layer?1RC What is the fuel density in units of kg/L?What mass and what volume of fuel should have been loaded? (1 lb = 453.6 g)Many laboratories use 25C as a standard temperature. What is this temperature in kelvins?The temperature on the surface of the Sun is 5.5 103 C. What is this temperature in kelvins?3PS Make the following temperature conversions:A marathon distance race covers distance of 42.195 km. What is this distance in meters? In miles?The average lead pencil, new and unused, is 19 cm long. What is its length in millimeters? In meters?A standard U.S. postage stamp is 2.5 cm long and 2.1 cm wide. What is the area of the stamp in square centimeters? In square meters?A compact disc has a diameter of 11.8 cm. What is the surface area of the disc in square centimeters? In square meters? [Area of a circle = ()(radius)2]A typical laboratory beaker has a volume of 250. mL What is its volume in cubic centimeters? In liters? In cubic meters?In cubic decimeters?Some soft drinks are sold in bottles with a volume of 1.5 L What is this volume in milliliters? In cubic centimeters? In cubic decimeters?A book has a mass of 2.52 kg. What is this mass in grams?A new U.S. dime has a mass of 2.265 g. What is its mass in kilograms? In milligrams?Ethylene glycol, C2H6O2, is an ingredient of automobile antifreeze. Its density is 1.11 g/cm3 at 20 C. If you need 500. mL of this liquid, what mass of the compound, in grams, is required?A piece of silver metal has a mass of 2.365 g. If the density of silver is 10.5 g/cm3, what is the volume of the silver?15PS Which occupies a larger volume, 600 g of water (with a density of 0.995 g/cm3) or 600 g of lead (with a density of 11.35 g/cm3)?You are on a diet that calls for eating no more than 1200 Cal/day What is this energy in joules?A 2-in. piece of chocolate cake with frosting provides 1670 kJ of energy. What is this in dietary Calories (Cal)?19PS 20PS You and your lab partner are asked to determine the density of an aluminum bar. The mass is known accurately (to four significant figures). You use a simple metric ruler to measure its dimensions and obtain the results for Method A. Your partner uses a precision micrometer and obtains the results for Method B The accepted density of aluminum is 2.702 g/cm3. (a) Calculate the average density for each method. Should all the experimental results be included in your calculations? If not, justify any omissions. (b) Calculate the percent error for each method's average value. (c) Calculate the standard deviation for each set of data. (d) Which method's average value is more precise? Which method is more accurate?The accepted value of the melting point of pureaspirin is 135 C. Trying to verify that value, you obtain 134 C, 136C133 C, and 138 C infour separate trials. Your partner finds 138 C,137 C, 138 C, and 138 C. (a) Calculate the average value and percent error for your data and your partner's data. (b) Which of you is more precise? More accurate?23PS 24PS 25PS 26PS To determine the average mass of a popcorn kernel, you collect the following data: Plot the data with number of kernels on the x-axis and mass on the y-axis. Draw the best straight line using the points on the graph (or do a least- squares or linear regression analysis using a computer program), and then write the equation for the resulting straight line. What is the slope of the line? What does the slope of the line signify about the mass of a popcorn kernel? What is the mass of 20 popcorn kernels? How many kernels are there in a handful of popcorn with a mass of 20.88 g?Use the following graph to answer the following question: (a) What is the value of x when y=4.0? (b) What is the value of y when x = 3.0? (c) What are the slope and the y-intercept of the line? (d) What is the value of y when x= 1.0?Use the graph below to answer the following questions. (a) Derive the equation for the straight line, = mx + b. (b) What is the value of y when x = 6.0?Solve the following equation for the unknown value, C. (0.502)(123) = (750)C Solve the following equation for the unknown value, n. (2.34)(15.6) = n(0.0821)(273)Solve the following equation for the unknown value, T. (4.184)(244)(T 292.0) + (0.449)(88.5)34PS Molecular distances are usually given in nanometers (1 nm = 1 109 m) or in picometers (1 pm = 1 1012 m). However, the angstrom () unit is sometimes used, where 1 = 1 1010 m. (The angstrom unit is not an SI unit.) If the distances between the Pt atom and the N atom in the cancer chemotherapy drug cisplatin is 1.97 , What is this distances in nanometers? In picometers?The separation between carbon atoms in diamond is 0.154 nm. What is their separation in meters? In picometers (pm)? In Angstroms ()?A red blood cell has a diameter of 7.5 m (micrometers). What is this dimension in (a) meters, (b) nanometers, and (c) picometers?The platinum-containing cancer drug cisplatin (Study Question 35) contains 65.0 mass-percent of the metal. If you have 1.53 g of the compound, what mass of platinum (in grams) is contained in this sample?39GQ You need a cube of aluminum with a mass of 7.6 g. What must be the length of the cube's edge (in cm)? (The density of aluminum is 2.698 g/cm3.)You have a 250.0-mL graduated cylinder containing some water. You drop three marbles with a total mass of 95.2 g into the water. What is the average density of a marble?42GQ The smallest repeating unit of a crystal of common salt is a cube (called a unit cell) with an edge length of 0.563 nm. (a) What is the volume of this cube in cubic nanometers? In cubic centimeters? (b) The density of NaCl is 2.17 g/cm3. What is the mass of this smallest repeating unit (unit cell)? (c) Each repeating unit is composed of four NaCl units. What is the mass of one NaCl formula unit?Diamond has a density of 3.513 g/cm3. The mass of diamonds is often measured in carats, where 1 carat equals 0.200 g. What is the volume (in cubic centimeters) of a 1.50-carat diamond?45GQ The density of pure water at various temperatures is given below. Suppose your laboratory partner tells you the density of water at 20 C is 0.99910 g/cmJ. Is this a reasonable number? Why or why not?47GQ The aluminum in a package containing 75 ft2 of kitchen foil weighs approximately 12 ounces. Aluminum has a density of 2.70 g/cm2What is the approximate thickness of the aluminum foil in millimeters? (1 ounce = 28.4 g)Fluoridation of city water supplies has been practiced in the United States for several decades. It is done by continuously adding sodium fluoride to water as it comes from a reservoir. Assume you live in a medium-sized city of 150,000 people and that 660 L (170 gal) of water is used per person per day. What mass of sodium fluoride (in kilograms) must be added to the water supply each year (365 days) to have the required fluoride concentration of 1 ppm (part per million)that is, 1 kilogram of fluoride per 1 million kilograms of water? (Sodium fluoride is 45.0% fluoride, and water has a density of 1.00 g/cm3.)About two centuries ago, Benjamin Franklin showed that 1 teaspoon of oil would cover about 0.5 acre of still water. If you know that 1.0 104 m2 = 2.47 acres and that there is approximately 5 cm3 in a teaspoon, what is the thickness of the 0.5-acre layer of oil? How might this thickness be related to the sizes of molecules?51GQ A 26-meter-tall statue of Buddha in Tibet is covered with 279 kg of gold. If the gold was applied toa thickness of 0.0015 mm, what surface area is covered (in square meters)? (Gold density = 19.3 g/cm3)At 25 C, the density of water is 0.997 g/cm3, whereas the density of ice at 10 C is 0.917 g/cm3. (a) If a soft-drink can (volume = 250. mL) is filled completely with pure water at 25 C and then frozen at - 10 C, what volume does the ice occupy? (b) Can the ice be contained within the can?Suppose your bedroom is 18 ft long and 15 ft wide, and the distance from floor to ceiling is 8 ft 6 in. You need to know the volume of the room in metric units for some scientific calculations. (a) What is the room's volume in cubic meters? In liters? (b) What is the mass of air in the room in kilograms? In pounds? (Assume the density of air is 1.2 g/L and that the room is empty of furniture.)A spherical steel ball has a mass of 3.475 g and a diameter of 9.40 mm. What is the density of the steel? |The volume of a sphere = (4/3)r3 where r = radius.]You are asked to identify an unknown liquid that is known to be one of the liquids listed below. You pipet a 3.50-mL sample into a beaker. The empty beaker had a mass of 12.20 g. and the beaker plus the liquid weighed 16.08 g. (a) Calculate the density and identify the unknown. (b) If you were able to measure the volume to only two significant figures (that is, 3.5 mL, not 3.50 mL), will the results be sufficiently accurate to identify the unknown? Explain You have an irregularly shaped piece of an unknown metal. To identify it, you determine its density and then compare this value with known values that you look up in the chemistry library. The mass of the metal is 74.122 g. Because of the irregular shape, you measure the volume by submerging the metal in water in a graduated cylinder. When you do this, the water level in the cylinder rises from 28.2 mL to 36.7 mL. (a) What is the density of the metal? (Use the correct number of significant figures in your answer.) (b) The unknown is one of the seven metals listed below. Isis possible to identify the metal based on the density you have calculated? Explain.There are five hydrocarbon compounds (compounds of C and II) that have the formula C6H14. (These are isomers; they differ in the way that C and H atoms are attached. Chapter 23) All are liquids at room temperature but have slightly different densities. (a) You have a pure sample of one of these hydrocarbons, and to identify it you decide to measure its density. You determine that a 5.0-mL sample (measured in a graduated cylinder) has a mass of 3.2745 g (measured on an analytical balance). Assume that the accuracy of the values for mass and volume is plus or minus one ( 1) in the last significant figure. What is the density of the liquid? (b) Can you identify the unknown hydrocarbon based on your experiment? (c) Can you eliminate any of the five possibilities based on the data? If so, which one(s)? (d) You need a more accurate volume measurement to solve this problem, and you redetermine the volume to be 4.93 mL Based on this new informationwhat is the unknown compound?Suppose you have a cylindrical glass tube with a thin capillary opening, and you wish to determine the diameter of the opening. You can do this experimentally by weighing a piece of the tubing before and after filling a portion of the capillary with mercury. Using the following information, calculate the diameter of the opening. Mass of tube before adding mercury = 3.263 g Mass of tube after adding mercury 3.416 g Length of capillary filled with mercury = 16.75 mm Density of mercury = 13.546 g/cm3 Volume of cylindrical capillary filled with mercury () (radius)2 (length)Copper: Copper has a density of 8.96 g/cm3 An ingot of copper with a mass of 57 kg (126 lb) is drawn into wire with a diameter of 9.50 mm. What length of wire (in meters) can be produced? [Volume of wire = ()(radius)2(length)]Copper: (a) Suppose you have a cube of copper metal that is 0.236 cm on a side with a mass of 0.1206 g. If you know that each copper atom (radius = 128 pm) has a mass of 1.055 1022 g (you will learn in Chapter 2 how to find the mass of one atom), how many atoms are there in this cube? What fraction of the cube is filled with atoms? (Or conversely, how much of the lattice is empty space?) Why is there empty space in the lattice? (b) Now look at the smallest, repeating unit of the crystal lattice of copper. Knowing that an edge of this cube is 361.47 pm and the density of copper is 8.960 g/cm3, calculate the number of copper atoms in this smallest, repeating unit.A sample of unknown metal is placed in a graduated cylinder containing water. The mass of the sample is 37.5 g, and the water levels before and after adding the sample to the cylinder are as shown in the figure. Which metal in the following list is most likely the sample? (d is the density of the metal.)Iron pyrite is often called fool's gold because it looks like gold (see page 11). Suppose you have a solid that looks like gold, but you believe it to be fool's gold. The sample has a mass of 23.5 g. When the sample is lowered into the water in a graduated cylinder (Study Question 63), the water level rises from 47.5 mL to 52.2 mL. Is the sample fool's gold (d = 5.00 g/cm3) or real gold (d = 19.3 g/cm3)?You can analyze for a copper compound in water using an instrument called a spectrophotometer. [A spectrophotometer is a scientific instrument that measures the amount of light (of a given wavelength) that is absorbed by the solution] The amount of light absorbed at a given wavelength of light (A) depends directly on the mass of compound per liter of solution. To calibrate the spectrophotometer, you collect the following data: Plot the absorbance (A) against the mass of copper compound per liter (g/L), and find the slope (m) and intercept (b) (assuming that A is y and the amount in solution is x in the equation for a straight line, y = mx + b). What is the mass of copper compound in the solution in g/L and mg/mL when the absorbance is 0.635?67IL 1. What is the mass of an iron atom with 30 neutrons? 2. A nickel atom with 32 neutrons has a mass of 59.930788 u. What is its mass in grams? 3. How many protons, neutrons, and electrons are in a 64Zn atom?1. The mass of an atom of manganese is 54.9380 u. How many neutrons are contained in one atom of this element? 25 29 30 55 An atom contains 12 neutrons and has a mass number of 23. Identify the element. (a) C (b) M (c) Na (d) Cl 1. Silver has two isotopes, one with 60 neutrons (percent abundance = 51.839%) and the other with 62 neutrons. What is the symbol of the isotope with 62 neutrons, and what is its percent abundance? , 51.839% , 48.161% , 51.839% , 48.161% 2. A naturally occurring sample of argon contains 2696 atoms of 36Ar, 504 atoms of 38Ar, and 7.968 × 105 atoms of40Ar. What is the percent abundance of the most abundant isotope? 99.60% 95.08% 7135% 99.92% Verify that the atomic weight of chlorine is 35.45, given the following information: 35CL mass = 34.96885 u; percent abundance = 75.77% 37Cl mass = 36.96590 u; percent abundance = 24.23%Neon has three stable isotopes, one with a small abundance. What are the abundances of the other two isotopes? 20Ne, mass = 19.992435 u; percent abundance = ? 21Ne mass = 20.993843 u; percent abundance = 027% 22Ne mass = 21.991383 u: percent abundance = ?1. Which is the more abundant isotope of copper, 63Cu or 65Cu? 63Cu 65Cu 2. Which of the following is closest to the observed abundance of 71Ga, one of two stable gallium isotopes (69Ga and 71Ga)? 20% 60% 70% 40% 3RC 1Q 2Q Which of the following elements is a metalloid? (a) Ge (b) S (c) Be (d) Al 2RC 3RC 4RC 1RC Give the number and identity of the constituent ions in each of the following ionic compounds; NaF, Cu(NO3)2 and NaCH3 CO2.(a) Write the formulas of all neutral ionic compounds that can be formed by combining the cations Na+ and Ba2+ with the anions S2 and PO43. (b) Iron forms ions having 2+ and 3+ changes. Write the formulas of the compounds formed between chloride ions and these two different iron cations.1RC 2RC 3RC The formula of barium acetate is (a) Ba(CH3CO2)2 (b) BaCH3CO2 (c) BaMnO4 (d) BaCO3 5. The name of the compound with the formula V2O3 is vanadium(III) oxide vanadium oxide divanadium trioxide vanadium trioxide Which should have the higher melting point, MgO or NaCl? (a) MgO (b) Nacl 1RC 2RC 3RC 4RC The density of gold, Au, is 19.32 g/cm3. What is the volume (in cubic centimeters) of a piece of gold that contains 2.6 × 1024 atoms? If you have 454 g of citric acid (H3C6H5O7), what amount (moles) does this represent? How many molecules? How many atoms of carbon?1RC Which of the following contains the largest number of molecules? (a) 24 g of O2 (b) 4.0 g of H2 (c) 19 g of F2 (d) 28 g of N2 Which of the following has the largest mass? (a) 0.50 mol Na (b) 0.20 mol K (c) 0.40 mol Ca (d) 0.60 mol Mg 4RC 5RC 1. Express the composition of ammonium carbonate, (NH4)2CO3, in terms of the mass of each element in 1.00 mol of compound and the mass percent of each element. 2. What is the mass of carbon in 454 g octane, C8H18?1. What is the empirical formula of naphthalene, C10H8? 2. The empirical formula of acetic acid is CH2O. If its molar mass is 60.05 g/mol, what is the molecular formula of acetic acid? 3. Isoprene is a liquid compound that can be polymerized to from natural rubber. It is composed of 88.17% carbon and 11.83% hydrogen. Its molar mass is 68.11 g/mal/ What are its empirical and molecular formulas? 4. Camphor is found in camphor wood, much prized for its wonderful odor. It is composed of 78.90% carbon and 10.59% hydrogen. The remainder is oxygen. What is its empirical formula?Gallium oxide, GaxOy forms when gallium is combine with oxygen. Suppose you allow 1.25 g of gallium (Ga) to react with oxygen and obtain 1.68 g of GaxOy. What is the formula of the product?Hydrated nickel(II) chloride is a beautiful green, crystalline compound. When heated strongly, the compound is dehydrated. If 0.235 g of NiCl2 xH2o gives 0.128 g of NiCl2 on heating, what is the value of x 1Q Salvarsan was long thought to be a single substance. Recently, however, a mass spectrometry study of the compound shows it to be a mixture of two molecules with the same empirical formula. Each has the composition 39.37% C, 3.304% H, 8.741% O, 7.652% N, and 40.932% As. One has a molar mass of 549 g/mol and the other has a molar mass of 915 g/mol. What are the molecular formulas of the compounds?To determine the density of atmospheric nitrogen. Lord Rayleigh removed the oxygen, water, and carbon dioxide from air, then filled an evacuated glass globe with the remaining gas. He determined that a mass of 0.20389 g of nitrogen has a density of 1.25718 g/L under standard conditions of temperature and pressure. What is the volume of the globe (in cm3)?The density of a mixture of gases may be calculated by summing the products of the density of each gas and the fractional volume of space occupied by that gas. (Note the similarity to the calculation of the molar mass of an element from the isotopic masses and fractional abundances.) Assume dry air with CO2 removed is 20.96% (by volume) oxygen. 78.11% nitrogen, and 0.930% argon. Determine the density of argon.Atmospheric argon is a mixture of three stable isotopes. 36Ar. 38Ar, and 40Ar. Use the information in the table below to determine the atomic mass and natural abundance of 40Ar.Given that the density of argon is 1.78 g/L under standard conditions of temperature and pressure, how many argon atoms are present in a room with dimensions 4.0 m 5.0 m 2.4 m that is filled with pure argon under these conditions of temperature and pressure?1. Which of the following hydrocarbons has the highest mass percentage of carbon? methane, CH4 ethane, C2H6 propane, C3H8 butane, C4H10 2. An organic compound has an empirical formula CH2O and a molar mass of 180 g/mol. What is its molecular formula? CH2O C6H12O6 C2H4O2 C5H10O5 Eugenol is the major component in oil of cloves. It has a molar mass of 164.2 g/mol and is 73.14% C and 737% H; the remainder is oxygen. What are the empirical and molecular formulas of eugenol? (a) C5H6O, C5H6O (b) C5H6O, C10H12O2 (c) C6H5O, C12H10,O2 (d) C3H6O, C6H12O2 4. Epsom salt is MgSO4 · 7H2O. When heated to 70 to 80°C it loses some, but not all, of its water of hydration. Suppose you heat 2.465 g of Epsom salt to 75°C and find that the mass is now only 1.744 g. What is the formula of the slightly dehydrated salt? Mg SO4 · 6H2O MgSO4 · 5H2O MgSO4 · 4H2O MgSO4 · 3H2O 1PS Define mass number. What is the difference between mass number and atomic mass?An atom has a very small nucleus surrounded by an electron cloud. Figure 2.1 represents the nucleus with a diameter of about 2 mm and describes the electron cloud as extending over 200 m. If the diameter of an atom is 1 10-8 cm, what is the approximate diameter of its nucleus?A gold atom has a radius of 145 pm. If you could string gold atoms like beads on a thread, how many atoms would you need to have a necklace 36 cm long?Give the complete symbol(ZAX), including atomic number and mass number, for each of the following atoms: (a) magnesium with 15 neutrons, (b) titanium with 26 neutrons, and (c) zinc with 32 neutrons.Give the complete symbol(ZAX), including atomic number and mass number, of (a) a nickel atom with 31 neutrons, (b) a plutonium atom with 150 neutrons, and (c) a tungsten atom with 110 neutrons.7PS Atomic structure. (a) The synthetic radioactive element technetium is used in many medical studies. Give the number of electrons, protons, and neutrons in an atom of technetium-99. (b) Radioactive americium-241 is used in house-hold smoke detectors and in bone mineral analysis. Give the number of electrons, protons, and neutrons in an atom of americium-241.9PS In 1886 Eugene Goldstein observed positively charged particles moving in the opposite direction to electrons in a cathode ray tube (illustrated below). From their mass, he concluded that these particles were formed from residual gas in the tube. For example, if the cathode ray tube contained helium, the canal rays consisted of He+ ions. Describe a process that could lead to these ions. Canal rays. In 1886, Eugene Goldstein detected a stream of particles traveling in the direction opposite to that of the negatively charged cathode rays (electrons). He called this stream of positive particles "canal rays:"Marie Curie was born in Poland but studied and carried out her research in Paris. In 1903, she shared the Nobel Prize in Physics with H. Becquerel and her husband Pierre for their discovery of radioactivity. (In 1911 she received the Nobel Prize in Chemistry for the discovery of two new chemical elements, radium and polonium, the latter named for her homeland, Poland.) They and others observed that a radioactive substance could emit three types of radiation: alpha (), beta (), and gamma (). If the radiation from a radioactive source is passed between electrically charged plates, some particles are attached to the positive plate, some to the negative plate, and others feel no attraction. Which particles are positively charged, which are negatively charged, and which have no charge? Of the two charged particles, which has the most mass? Radioactivity. Alpha (), beta I(), and gamma () rays from a radioactive element are separated by passing them between electrically charged plates.12PS The mass of an 16 O atom is 15.995 u. What is its mass relative to the mass of an atom of 12C?What is the mass of one 16O atom, in grams? (The mass of an 16O atom is 15.995 u.)Cobalt has three radioactive isotopes used in medical studies. Atoms of these isotopes have 30, 31, and 33 neutrons, respectively. Give the complete symbol for each of these isotopes.Naturally occurring silver exists as two isotopes having mass numbers 107 and 109. How many protons, neutrons, and electrons are there in each of these isotopes?Name and describe the composition of the three hydrogen isotopes.Which of the following are isotopes of element X, the atomic number for which is 9: 919X, 920X, 189X, and 921X?Thallium has two stable isotopes, 203TIand 205Tl. Knowing that the atomic weight of thallium is 204.4, which isotope is the more abundant of the two?Strontium has four stable isotopes. Strontium-84 has a very low natural abundance, but 86Sr, 87Sr, and 88Sr are all reasonably abundant. Knowing that the atomic weight of strontium is 87.62, which of the more abundant isotopes predominates?Verify that the atomic weight of lithium is 6.94, given the following information: 6Li, mass = 6.015121 u; percent abundance = 7.50% 7Li, mass = 7.016003 u; percent abundance = 92.50%Verify that the atomic weight of magnesium is 24.31, given the following information: 24Mg, mass = 23.985042 u; percent abundance = 78.99% 25Mg, mass = 24.985837 u; percent abundance = 10.00% 26Mg, mass = 25.982593 u; percent abundance = 11.01%Gallium has two naturally occurring isotopes, 69Ga and 71Ga, with masses of 68.9257 u and 70.9249 u, respectively. Calculate the percent abundances of these isotopes of gallium.Europium has two stable isotopes, 151Eu and 153Eu, with masses of 150.9197 u and 152.9212 u, respectively. Calculate the percent abundances of these isotopes of europium.Titanium and thallium have symbols that are easily confused with each other. Give the symbol, atomic number, atomic weight, and group and period number of each element. Are they metals, metalloids, or nonmetals?In Groups 4A-6A, there are several elements whose symbols begin with S. Name these elements, and for each one give its symbol, atomic number, group number, and period. Describe each as a metal, metalloid, or nonmetal.How many periods of the periodic table have 8 elements, how many have 18 elements, and how many have 32 elements?28PS 29PS 30PS Classify the following elements as metals, metalloids, or nonmetals: N, Na, Ni, Ne, and Np.32PS 33PS 34PS What is the charge on the common monatomic ions of the following elements? (a) magnesium (b) zinc (c) nickel (d) gallium What is the charge on the common monatomic ions of the following elements? (a) selenium (b) fluorine (c) iron (d) nitrogen 37PS 38PS When a potassium atom becomes a monatomic ion, how many electrons does it lose or gain? What noble gas atom has the same number of electrons as a potassium ion?When oxygen and sulfur atoms become monatomic ions, how many electrons does each lose or gain? Which noble gas atom has the same number of electrons as an oxide ion? Which noble gas atom has the same number of electrons as a sulfide ion?41PS 42PS Give the formula and the number of each ion that makes up each of the following compounds: (a) K2S (b) CoSO4 (c) KMnO4 (d) (NH4)3PO4 (e) Ca(CIO)2 (f)NaCH3CO2 Give the formula and the number of each ion that makes up each of the following compounds: (a) Mg(CH3CO2)2 (b) Al(OH)3 (c) CuCO3 (d) Ti(SO4)2 (e) KH2PO4 (f)CaHPO4 45PS 46PS 47PS 48PS 49PS 50PS 51PS 52PS Write the formulas for the four ionic compounds that can be made by combining each of the cations Na+ and Ba2+ with the anions CO32- and l. Name each of the compounds.Write the formulas for the four ionic compounds that can be made by combining the cations Mg2+ and Fe3+ with the anions PO43 and NO3. Name each compound formed.Sodium ions, Na+, form ionic compounds with fluoride ions, F, and iodide ions, I. The radii of these ions are as follows: Na+ = 116 pm; F = 119 pm; and l = 206 pm. In which ionic compound, NaF or Nal, are the forces of attraction between cation and anion stronger? Explain your answer.Consider the two ionic compounds NaCl and CaO. In which compound are the cation-anion attractive forces stronger? Explain your answer.57PS Name each of the following binary, nonionic compounds: (a) N2O5 (b) P4S3 (c) OF2 (d) XeF4 59PS 60PS Calculate the mass, in grams, of each the following: (a) 2.5 mol of aluminum (b) 1.25 103 mol of iron (c) 0.015 mol of calcium (d) 653 mol of neon Calculate the mass, in grams, of each the following: (a) 4.24 mol of gold (b) 15.6 mol of He (c) 0.063 mol of platinum (d) 3.63 104 mol of Pu Calculate the amount (moles) represented by each of the following: (a) 127.08 g of Cu (b) 0.012 g of lithium (c) 5.0 mg of americium (d) 6.75 g of Al Calculate the amount (moles) represented by each of the following: (a) 16.0 g of Na (b) 0.876 g of tin (c) 0.0034 g of platinum (d) 0.983 g of Xe You are given 1.0-g samples of He, Fe, Li, Si, and C. Which sample contains the largest number of atoms? Which contains the smallest?You are given 0.10-g samples of K, Mo, Cr, and Al. List the samples in order of the amount (moles), from smallest to largest.Analysis of a 10.0-g sample of apatite (a major component of tooth enamel) showed that it was made up of 3.99 g Ca, 1.85 g P, 4.14 g O, and 0.020 g H. List these elements based on relative amounts (moles), from smallest to largest.A semiconducting material is composed of 52 g of Ga, 9.5 g of Al, and 112 g of As. Which element has the largest number of atoms in this material?Calculate the molar mass of each of the following compounds: (a) Fe2O3, iron(III) oxide (b) BCI3, boron trichloride (c) C6H8O6, ascorbic acid (vitamin C)Calculate the molar mass of each of the following compounds: (a) Fe(C6H11O7)2, iron(II) gluconate, a dietary supplement (b) CH3CH2CH2CH2SH, butanethiol. has a skunk-like odor (c) C20H24N2O2, quinine, used as an antimalarial drug Calculate the molar mass of each hydrated compound. Note that the water of hydration is included in the molar mass. (See page 85.) (a) Ni(NO3)2 6 H2O (b) CuSO4 5 H2O 72PS What mass is represented by 0.0255 mol of each of the following compounds? (a) C3H7OH, 2-propanol, rubbing alcohol (b) C11H16O2, an antioxidant in foods, also known as BHA (butylated hydroxyanisole) (c) C9H8O4, aspirin (d) (CH3) 2CO, acetone, an important industrial solvent Assume you have 0.123 mol of each of the following compounds. What mass of each is present? (a) C14H10O4, benzoyl peroxide, used in acne medications (b) Dimethylglyoxime, used in the laboratory to test for nickel(II) ions (c) The compound below, responsible for the "skunky" taste in poorly made beer. (d) DEFT, a mosquito repellent Sulfur trioxide, SO3, is made industrially in enormous quantities by combining oxygen and sulfur dioxide SO2. What amount (moles) of SO3 is represented by 1.00 kg of sulfur trioxide? How many molecules? How many sulfur atoms? How many oxygen atoms?How many ammonium ions and how many sulfate ions are present in a 0.20 mol sample of (NH4)2SO4? How many atoms of N, H, S and O are contained in this sample?Acetaminophen, whose structure is drawn below, is the active ingredient in some nonprescription pain killers. The recommended dose for an adult is two 500-mg caplets. How many molecules make up one dose of this drug?An Alka-Seltzer tablet contains 324 mg of aspirin (C.9H8O4,), 1904 mg of NaHCO3, and 1000. mg of citric add (H3C6H5O7). (The last two compounds react with each other to provide the "fizz," bubbles of CO2, when the tablet is put into water.) (a) Calculate the amount (moles) of each substance in the tablet. (b) If you take one tablet, how many molecules of aspirin are you consuming?Calculate the mass percent of each element in the following compounds: (a) PbS, lead(I1) sulfide, galena (b) C3H8, propane (c) C10H14O, carvone, found in caraway seed oil Calculate the mass percent of each element in the following compounds: (a) C8H10N2O2, caffeine (b) C10H20O menthol (c) CoCl2 6 H2O Calculate the mass percent of copper in CuS, copper(II) sulfide. If you wish to obtain 10.0 g of copper metal from copper(II) sulfide, what mass of CuS (in grams) must you use?Calculate the mass percent of titanium in the mineral ilmenite, FeTiO3. What mass of ilmenite (in grams) is required if you wish to obtain 750 g of titanium?Succinic acid occurs in fungi and lichens. Its empirical formula isC2H3O2, and its molar mass is 118.1 g/mol. What is its molecular formula?An organic compound has the empirical formula C2H4NO. If its molar mass is 116.1 g/mol, what is the molecular formula of the compound?85PS Complete the following table:Acetylene is a colorless gas used as a fuel in welding torches, among other things. It is 92.26% C and 7.74% H. Its molar mass is 26.02 g/mol. What are the empirical and molecular formulas of acetylene?A large family of boron-hydrogen compounds has the general formula BxHy. One member of this family contains 88.5% B; the remainder is hydrogen. What is its empirical formula?Cumene, a hydrocarbon, is a compound composed only of C and H. It is 89.94% carbon, and its molar mass is 120.2 g/mol. What are the empirical and molecular formulas of cumene?In 2006, a Russian team discovered an interesting molecule they called sulflower because of its shape and because it was based on sulfur. It is composed of 57.17% S and 42.83% C and has a molar mass of 448.70 g/mol. Determine the empirical and molecular formulas of sulflower.Mandelic acid is an organic acid composed of carbon (63.15%), hydrogen (5.30%), and oxygen (31.55%). Its molar mass is 152.14 g/mol. Determine the empirical and molecular formulas of the acid.Nicotine, a poisonous compound found in tobacco leaves, is 74.0% C, 8.65% H, and 17.35% N. Its molar mass is 162 g/mol. What are the empirical and molecular formulas of nicotine?A compound containing xenon and fluorine was prepared by shining sunlight on a mixture of Xe (0.526 g) and excess F2 gas. If you isolate 0.678 g of the new compound, what is its empirical formula?Elemental sulfur (1.256 g) is combined with fluorine, to give a compound with the formula SFx, a very stable, colorless gas. If you have isolated 5.722 g of SFx, what is the value of x?Epsom salt is used in tanning leather and in medicine. It is hydrated magnesium sulfate, MgSO4 7 H2O. The water of hydration is lost on heating, with the number lost depending on the temperature. Suppose you heat a 1.394-g sample at 100 C and obtain 0.885 g of a partially hydrated sample, MgSO4 x H2O. What is the value of x?You combine 1.25 g of germanium, Ge, with excess chlorine, Cl2. The mass of product, GexCly, is 3.69 g. What is the formula of the product, CexCly?Fill in the blanks in the table (one column per element).Potassium has three naturally occurring isotopes (39K, 40K, and 41K), but 40K has a very low natural abundance. Which of the other two isotopes is more abundant? Briefly explain your answer.Crossword Puzzle: In the 2 2 box shown here, each answer must be correct four ways: horizontally, vertically, diagonally, and by itself. Instead of words, use symbols of elements. When the puzzle is complete, the four spaces will contain the over-lapping symbols of 10 elements. There is only one correct solution. Horizontal 12: two-letter symbol for a metal used in ancient times 34: two-letter symbol for a metal that burns in air and is found in Croup 5A Vertical 13: two-letter symbol for a metalloid 24: two-letter symbol for a metal used in U.S. coins Single squares: All one-letter symbols 1: a colorful non-metal 2: colorless, gaseous non-metal 3: an element that makes fireworks green 4: an element that has medicinal uses Diagonal 1-4: two-letter symbol for an element used in electronics 2-3: two-letter symbol for a metal used with Zr to make wires for superconducting magnets This puzzle first appeared in Chemical Engineering News, p. 86, December 14, 1987 (submitted by S. J. Cyvin) and in Chem Matters, October 1988.The following chart shows a general decline in abundance with increasing mass among the first 30 elements. The decline continues beyond zinc. Notice that the scale on the vertical axis is logarithmic, that is, it progresses in powers of 10. The abundance of nitrogen, for example, is 1/10,000 (1/104) of the abundance of hydrogen. All abundances are plotted as the number of atoms per 102 atoms of H. (The fact that the abundances of Li, Be, and B, as well as those of the elements near Fe, do not follow the general decline is a consequence of the way that elements are synthesized in stars.) (a) What is the most abundant main group metal? (b) What is the most abundant nonmetal? (c) What is the most abundant metalloid? (d) Which of the transition elements is most abundant? (e) Which halogens are included on this plot, and which is the most abundant?Copper atoms. (a) What is the average mass of one copper atom? (b) Students in a college computer science class once sued the college because they were asked to calculate the cost of one atom and could not do it. But you are in a chemistry course, and you can do this. (See E. Felsenthal, Wall Street Journal, May 9, 1995.) If the cost of 2.0-mm diameter copper wire (99.9995% pure] is currently 41.70 for 7.0 g, what is the cost of one copper atom?102GQ

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