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All Textbook Solutions for Conceptual Physical Science Explorations
A certain radioactive element has a half-life of 1 hour. If you start with a 1-gram sample of the element at noon, how much of this same element will be left at 3.00PM ? (a) 0.5 grams (b) 0.25 grams (c) 0.125 grams (d) 0.0625 grams9RATIf an iron nucleus split in two, its fission fragments would have (a) more mass per nucleon. (b) less mass per nucleon. (c) the same mass per nucleon. (d) either more or less mass per nucleon.1RQ2RQWhat do the members of the Chemical Manufacturers Association pledge in the Responsible Care program?4RQHow does the arrangement of particles in a gas differ from the arrangements in liquids and solids?6RQWhat is it called when evaporation occurs beneath the surface of a liquid?Which is greater: waters heat of fusion or its heat of vaporization?What happens to the chemical identity of a substance during a physical change?What is a chemical bond?What changes during a chemical reaction?12RQWhy is the rusting of iron considered to be a chemical change?14RQ15RQ16RQWhat is the difference between an element and a compound?What does the chemical formula of a substance tell us about that substance?What is the chemical formula for the compound titanium dioxide?Why are common names often used for chemical compounds instead of systematic names?Water molecules vibrate and jostle about at different speeds depending upon where they are located. Rank the speed of water molecules found in a steam-hot geyser, a frozen glacier and a flowing river2TC3TC1TEOf the three sciences physics, chemistry, and biology, which is the most complex?3TE4TE5TE6TE7TEWhich has stronger attractions among its submicroscopic particles: a solid at 25C or a gas of a different substance at 25C? Explain.Which occupies the greatest volume: 1 g of liquid water, or 1 g of water vapour?10TEYou take 50mL of water and combine it with 50mL of purified alcohol and you get a total of 98mL of mixture. Explain.12TEWhat physical and chemical changes occur when a wax candle burns?14TE15TE16TEOxygen atoms are used to make water molecules. Does this mean that oxygen, O2, and water, H2O, have similar properties?18TEWhat is the chemical name for a compound with the formula Ba3N2 ?20TEChemistry is the study of (a) matter. (b) transformations of matter. (c) the submicroscopic realm. (d) All of the above.Imagine that you can see individual molecules. You watch a small collection of molecules that are moving around slowly while vibrating and bumping against each other. The slower-moving molecules then start to line up, but as they do so their vibrations increase. Soon all the molecules are aligned and vibrating about fixed positions. What is happening? (a) The sample is being cooled and the material is freezing. (b) The sample is being heated and the material is melting. (c) The sample is being cooled and the material is condensing. (d) The sample is being heated and the material is boiling.What chemical change occurs when a wax candle burns? (a) The wax near the flame melts. (b) The molten wax is pulled upwards through the wick. (c) The wax within the wick is heated to about 600C0 . (d) The heated wax molecules combine with oxygen molecules.The phase in which atoms and molecules no longer move is the (a) solid phase (b) liquid phase (c) gas phase. (d) None of the above.5RAT6RAT7RATIf you have one molecule ofTiO2 , how many molecules of O2 does it contain? One; TiO2 is a mixture of Ti and O2. None; O2 is a different molecule from TiO2. Two; TiO2 is a mixture of Ti and 2 O . Three; TiO2 contains three molecules.9RAT10RAT1RQHow many unpaired valence electrons are there in the carbon atom?To become a negative ion, does an atom lose or gain electrons?Why does the fluorine atom tend to gain only one electron?5RQ6RQWhy do all minerals have such high melting points?Why are all crystals of the mineral halite, NaCl, cubic?9RQWhat is the electric charge on the calcium ion in calcium chloride, CaCl2?Do metals more readily gain or lose electrons?What is an alloy?13RQ14RQ15RQ16RQHow can a molecule be nonpolar when it consists of atoms that have different electronegativities?Which would you describes as **#x201Cstickier”: a polar molecule or a nonpolar one?19RQAre induced dipoles permanent?Rank the following bonds in order of increasing polarity: (a) CH (b) OH (c) NH2TC1TE2TEWhy does the potassium tend to lose only one electron?4TETwo fluorine atoms join together to form a covalent bond. Why dont two potassium atoms do the same thing?6TE7TEWhich bond is most polar: (a) HN (b) NC (c) CO (d) CC (e) OH (f) CHWhy dont the dipoles of the two hydrogen-oxygen bonds in a water molecule cancel each other out?How many nonbonding pairs of electrons are there in the oxygen atom of a water molecule? How many bonding pairs?The oxygen atom of a water molecule has four pairs of electrons in its outermost shell. Do you suppose all these pairs tend to bunch together on the same side of the atom, or do these pairs tend to spread out as far apart from each other as possible. Why?If water were linear like carbon dioxide, would it be polar or nonpolar? Would its boiling point be higher or lower than 100Co?Why dont oil and water mix?Water, H2O, and methane, CH4, have about the same mass and differ by only one type of atom. Why is the boiling point of water so much higher than that of methane?Two kids are sitting across from each other at a table trading their jellybeans. They both start out with the same number of jellybeans, but one of the kids is in a generous mood while the other is in a greedy mood. If each jellybean represents an electron, which kid ends up being slightly negative: the generous kid or the greedy kid? Who ends up being slightly positive? Is the generous kid just as negative as the greedy kid is positive? Would you describe this as a polar or nonpolar situation? What if both kids were equally greedy?Which is stronger: the covalent bond that holds atoms together within a molecule or the electrical attraction between two neighbouring molecules?Why is a water molecule more attracted to a calcium ion than a sodium ion?The charges with sodium chloride are all balanced - for every positive sodium ion there is a corresponding negative chloride ion. Since its charges are balanced, how can sodium chloride be attracted to water, and vice versa?How are oxygen molecules attracted to water molecules?Some bottled water is now advertised as containing extra quantities of Vitamin O, which is a marketing gimmick for selling oxygen, O2. Might this bottled water actually contain extra quantities of oxygen? How much more than one might find in regular bottled water? How might the amount of oxygen we absorb through our lungs compare to that we might absorb through our stomach after burping?1RATAluminum ions carry a +3 charge, and chloride ions carry a 1 charge. What would be the chemical formula for the ionic compound aluminum chloride? (a) Al3Cl (b) AlCl3 (c) Al3Cl3 (d) AlCl3RATAtoms of metallic elements can form ionic bonds, but they are not very good at forming covalent bonds. Why? (a) These atoms are too large to be able to come in close contact with other atoms. (b) They have a great tendency to lose electrons. (c) Their valence shells are already filled with electrons. (d) They are on the wrong side of the periodic table.In terms of the periodic table, is there an abrupt or gradual change between ionic and covalent bonds? (a) An abrupt change that occurs across the metalloids. (b) Actually, any element of the periodic table can form a covalent bond. (c) There is a gradual change: the farther apart, the more ionic. (d) Whether an element forms one or the other depends on nuclear charge and not the relative positions in the periodic table.A hydrogen atom does not form more than one covalent bond because it (a) has only one shell of electrons. (b) has only one electron to share. (c) loses its valence electron so readily. (d) has such a strong electronegativity.When nitrogen and fluorine combine to form a molecule, the most likely chemical formula is (a) N 3 F (b) N 2 F (c) NF 4 (d) NF (e) NF 3A substance consisting of which molecule shown below should have a higher boiling point? S=C=O O=C=O (a) The molecule on the left, SCO, because it comes later in the periodic table. (b) The molecule on the left, SCO, because it has less symmetry. (c) The molecule on the right, OCO, because it has more symmetry. (d) The molecule on the right, OCO, because it has more mass.9RATWhat is a hydrogen bond? (a) The covalent bond between two hydrogen atoms (b) A strong glue commonly found in hardware stores (c) An unusually strong dipole-dipole attraction (d) A type of nuclear explosive1RQ2RQ3RQ4RQHow is a solution different from a suspension?How can a solution be distinguished from a suspension?What happens to the volume of a sugar solution as more sugar is dissolved in it?Why is a ruby considered to be a solution?9RQWhat does it mean to say that a solution is concentrated?Is 1 mole of particles a very large number of particles or a very small number?Is concentration typically given with the volume of solvent or the volume of solution?Why does the solubility of a gas solute in a liquid solvent decrease with increasing temperature?Why do sugar crystals dissolve faster when crushed?Is sugar a polar or nonpolar substance?Water and soap are attracted to each other by what type of electrical attraction?What is difference between a soap and a detergent?Why is treated water sprayed into the air prior to being piped to users?What are two ways in which people disinfect water in areas where municipal treatment facilities are not available?What naturally occurring element has been contaminating the water supply of Bangladesh?Rank the following solutions in order of increasing concentration: Solution A, 0.5moles of sucrose in 2.0liters of solution; Solution B, 1.0moles of sucrose in 3.0liters of solution, Solution C, 1.5moles of sucrose in 4.0liters of solution.Rank the following compounds in order of increasing solubility in water:Which of the following boxes contains an element? A compound? A mixture? How many different types of molecules are shown altogether in all three boxes?Why cant the elements of a compound be separated from one another by physical means?Which of the above best represents a suspension?Which of the above best represents a solution?Which of the above best represents a compound?Many dry cereals are fortified with iron, which is added to the cereal in the form of small iron particles. How might these particles be separated from the cereal?The boiling point of 1,4-butanediol is 230C. Would you expect this compound to be soluble or insoluble in room-temperature water? Explain.Why does oxygen have such a low solubility in water?Why does the solubility of a gas solute in a liquid solvent decrease with increasing temperature?10TEDistinguish between a saturated solution and an unsaturated solution.12TEWhy is it not possible to calculate the concentration of a solution that contains 2moles of sugar in 10L of water?14TEWhat is the count of sugar molecules in 0.5moles of sugar?How necessary is soap for removing salt from your hands? Why?When you set a pot of tap water on the stove to boil, youll often see bubbles start to form well before boiling temperature is reached. Explain this observation.18TEMany homeowners get their drinking water pipes up from wells dug on their property. Sometime this well water smells bad because of trace quantities of the gaseous compound hydrogen sulphide, H2S . How might this odor be removed from water already taken from the tap?Why is flushing a toilet with clean water from a municipal supply about as wasteful as flushing it with bottled water?Assume the total number of molecules in a sample of liquid is about 3 million trillion. One million trillion of these are molecules of some poison, while 2 million trillion of these are water molecules. Show that the purity of this water is about 67%.Assume the total number of molecules in a glass of liquid is about 1,000,000 million trillion. One million trillion of these are molecules of some poison, while 999,999 million trillion of these are water molecules. What is the purity of the water? In other words, what percentage of all the molecules in the glass is water?3TSHow much sodium chloride, in grams, is needed to make 15L of a solution that has a concentration of 3.0g of sodium chloride per litre of solution?If water is added to 1 mole of sodium chloride in a flask until the volume of the solution is 1L, what is the molarity of the solution? What is the molarity when water is added to 2 moles of sodium chloride to make 0.5L of solution?Someone argues that he or she doesnt drink tap water because it contains thousands of molecules of some impurity in each glass. How would you respond in defense of the waters purity, if it indeed does contain thousands of molecules of some impurity per glass? (a) Impurities arent necessarily bad, in fact, they may be good for you. (b) The water contains water molecules and each water molecule is pure. (c) Theres no defense. If the water contains impurities, it should not be drunk. (d) Compared to the billions and billions of water molecules, a thousand molecules of something else is practically nothing.What is the difference between a compound and a mixture? (a) They both consist of atoms from different elements. (b) The way in which their atoms are bonded together. (c) One is solid and the other is a liquid. (d) The components of a mixture are not chemically bonded together.3RATWhy is half-frozen fruit punch always sweeter than the same fruit punch completely melted? (a) Because the sugar sinks to the bottom (b) Because sugar molecules dont crystalize with the water (c) Because the half-frozen fruit punch is warmer (d) Because sugar molecules precipitate as crystalsHow many grams of sugar (sucrose) are there in 5L of sugar water that has a concentration of 0.5g per liter of solution? (a) 50g (b) 25g (c) 2.5g (d) 1.5gSuggest why sodium chloride, NaCl, is insoluble in gasoline. Consider the electrical attractions. (a) Since this molecule is so small, there is not much opportunity for the gasoline to interact with it through any electrical attractions. (b) Since gasoline is a very polar molecule, the salt can only form dipoleinduced dipole bonds, which are very weak, giving it a low solubility in gasoline. (c) Since gasoline is so strongly attracted to itself, the salt, NaCl, is excluded. (d) Salt is composed of ions that are too attracted to themselves. Gasoline is nonpolar so salt and gasoline will not interact very well.Fish dont live very long in water that has just been boiled and brought back to room temperature. Suggest why. (a) There is now a higher concentration of dissolved CO2 in the water. (b) The nutrients in the water have been destroyed. (c) Since some of the water was evaporated while boiling, the salts in the water are now more concentrated. This has a negative effect on the fish. (d) The boiling process removes the air that was dissolved in the water. Upon cooling, the water is void of its usual air content, hence, the fish drown.Would you expect to find more dissolved oxygen in polar or tropical ocean waters? Why? (a) There would be more dissolved oxygen in the tropical oceans because intense tropical storms mix up the atmospheric oxygen into the ocean water. (b) There would be more dissolved oxygen in the polar oceans because the colder oxygen would sink and dissolve into the water. (c) There would be more dissolved oxygen in the tropical oceans because the heated oxygen molecules in the air would collide with and mix into the water. (d) There would be more dissolved oxygen in the polar oceans because the solubility of oxygen in water decreases with increasing temperature.What is the boiling temperature of a single water molecule? Does this question make sense? a) Boiling involves the separation of many molecules (plural). With only one molecule, the concept of boiling is meaningless. b) Yes, this question does make sense because temperature measures the average kinetic energy of a molecule, which is 100C for water. c) 100C indicates when the covalent bonds of the water molecule have been broken to give rise to hydrogen and oxygen atoms, which are released into atmosphere. d) No, this question does not make sense because you need at least two molecules to get the average kinetic energy.10RAT1RQ2RQ3RQ4RQ5RQWhat generally happens to the rate of a chemical reaction with increasing temperature?Which reactant molecules are the first to pass over the energy barrier?What term is used to describe the minimum amount of energy required in order for a reaction to proceed?What catalyst is effective in the destruction of atmospheric ozone, O3 ?What is the purpose of a catalytic converter?11RQWhat net effect does a chemical reaction have on a catalyst?Why are catalysts so important to our economy?14RQIs there any energy consumed at any time during an exothermic reaction?What is released by an exothermic reaction?What is absorbed by an endothermic reaction?As energy disperses, where does it go?What is always increasing?20RQ1TCRank the following covalent bonds in order of increasing bond strength: (a) CC (b) C=C (c) CC1TE5TEWhat two aspects of a collision between two reactant molecules determine whether or not the collision results in the formation of product molecules?Why does a glowing splint of wood burn only slowly in air but burst into flames when placed in pure oxygen?Why is heat often added to chemical reactions performed in the laboratory?9TE10TE11TE12TE13TE14TEUnder what conditions will a hot pie not lose heat to its surroundings?16TEExothermic reactions are favored because they release heat to the environment. Would an exothermic reaction be more favored or less favored if it were carried out within a superheated chamber?What role does entropy play in chemical reactions?A gardener finds weeds growing all by themselves within her garden. Yet these weeds, she knows, are plants, which are a form of concentrated energy. She wonders whether the growing of these weeds is a violation of the laws of entropy. What do you tell her?20TEUse the bond energies in Table 20.1 and the accounting format shown in Section 20.3 to determine whether these reactions are exothermic or endothermic: (a) H2+Cl22HCl (b) 2HCCH+5O24CO2+2H2OUse the bond energies in Table 20.1 and the accounting format shown in Section 20.3 to determine whether these reactions are exothermic or endothermic: (a) H2NNH2H2+H2+N2 (b) 2H2O2O2+2H2O1RAT2RAT3RAT4RATThe yeast in bread dough feeds on sugar to produce carbon dioxide. Why does the dough rise faster in a warmer area? (a) There is a greater number of effective collisions among reacting molecules. (b) Atmospheric pressure decreases with increasing temperature. (c) The yeast tends to wake up with warmer temperatures, which is why bakers yeast is best stored in the refrigerator. (d) The rate of evaporation increases with increasing temperature.What can you deduce about the activation energy of a reaction that takes billions of years to go to completion? How about a reaction that takes only fractions of a second? (a) The activation energy of both these reactions must be very low. (b) The activation energy of both these reactions must be very high. (c) The slow reaction must have a high activation energy while the fast reaction must have a low activation energy. (d) The slow reaction must have a low activation energy while the fast reaction must have a high activation energy.What role do CFCs play in the catalytic destruction of ozone? (a) Ozone is destroyed upon binding to a CFC molecule that has been energized by ultraviolet light. (b) There is no strong scientific evidence that CFCs play a significant role in the catalytic destruction of ozone. (c) CFC molecules activate chlorine atoms into their catalytic action. (d) CFC molecules migrate to the stratosphere where they generate chlorine atoms upon being destroyed by ultraviolet light.8RATHow much energy, in kilojoules, is released or absorbed from the reaction of 1 mole of nitrogen, N2, with three moles of molecular hydrogen, H2, to form 2 moles of ammonia, NH3? Consult Table 20.1 for bond energies. (a) +899kJ/mol (b) 993kJ/mol (c) +80kJ/mol (d) 80kJ/mol10RATWhen an acid is dissolved in water, what ion does the water form?When a chemical loses a hydrogen ion, is it behaving as an acid or a base?Why does a solution of a strong acid conduct electricity better than a solution of a weak acid having the same concentration?When can a solution of a weak base be more corrosive than a solution of a strong base?Is water a strong acid or a weak acid?What is true about the relative concentrations of hydronium and hydroxide ions in an acidic solution? How about a neutral solution? A basic solution?What does the pH of a solution indicate?What is the product of the reaction between carbon dioxide and water?How do humans generate the air pollutant sulfur dioxide?10RQ11RQWhat is the difference between an oxidizing agent and a reducing agent?What is electrochemistry?What is the prime difference between a battery and a fuel cell?What is electrolysis, and how does it differ from what goes on inside a battery?16RQ17RQWhat happens to the polarity of oxygen atoms as they transform from molecular oxygen, O2, into water molecules, H2O?What do we do to food molecules to obtain energy from them?What gas, when provided in the right concentration, has been shown to induce a state of suspended animation in mice?Rank the following solutions in order of increasing concentration of hydronium ions, H3O+: (a) hydrogen chloride, HCl (concentration= 2M) (b) acetic acid, CH3COOH (concentration= 2M) (c) ammonia, NH3, (concentration= 2M)2TCReview the concept of electronegativity in Section 18.6 and rank the following elements from the weakest to strongest oxidizing agent: (a) chlorine, Cl (b) sulfur. S (c) sodium, NaIdentify the acid or base behavior of each substance in these reactions: (a) H3O++ClH2O+HCl (b) H2PO4+H2OH3O++HPO4What happens to the corrosive properties of an acid and a base after they neutralize each other? Why?Why do we use the pH scale to indicate the acidity of a solution rather than simply stating the concentration of hydronium ions?Water is formed from the reaction between an acid and a base. Why is water not classified as a salt?What happens to the pH of an acidic solution as pure water is added?6TEPour vinegar onto beach sand from the Caribbean and the result is a lot of froth and bubbles. Pour vinegar onto beach sand from California, however, and nothing happens. Why?8TEWhat happens to the pH of water as you blow bubbles into it through a drinking straw?10TE11TEWhat element behaves as the oxidizing agent in the following equation and what element behaves as the reducing agent? Sn2++2AgSn+2Ag+The type of iron that the human body needs for good health is the Fe2+ ion. Cereals fortified with iron, however, usually contain small grains of elemental iron, Fe . What must the body do to this elemental iron to make good use of it? Oxidation or reduction?Water is 88.88 oxygen by mass. Oxygen is exactly what a fire needs to grow brighter and stronger. So why doesnt a fire grow brighter and stronger when water is added to it?15TE16TEAs we digest and subsequently metabolize food, is the food gradually oxidized or reduced? What evidence do you have?How is suspended animation similar to death? How is it different?Are hydrogen sulfide, H2S and oxygen, O2 , molecules very different in size or about the same size?Assuming the technique of suspended animation was safe, which it currently isnt, what would be some of the disadvantages to putting yourself under suspended animation for a long period of time?Show that the pH of a solution is 10 when the hydronium ion concentration of this solution is 11010M . Is the solution acidic or basic?When the hydronium ion concentration of a solution is 1104M , what is the pH of the solution? Is the solution acidic or basic?3TSShow that the pH of a solution is 0.301 when its hydronium ion concentration equals 2 moles per liter. Is the solution acidic or basic?What is the relationship between the hydroxide ion and a water molecule? (a) A hydroxide ion is a water molecule plus a proton. (b) A hydroxide ion and a water molecule are the same things. (c) A hydroxide ion is a water molecule minus a hydrogen nucleus. (d) A hydroxide ion is a water molecule plus two extra electrons.Water is formed from the reaction of an acid and a base. Why is it not classified as a salt? (a) Not all acid-base reactions produce a salt, as in the case with the formation of water. (b) The attraction between the two ions in water molecules are too strong. (c) By definition, a salt must be able to dissolve in water, so water itself cannot be called a salt. (d) A salt is an ionic compound, whereas water is a covalent compound.What happens to the corrosive properties of an acid and a base after they neutralize each other? Why? (a) The corrosive properties are neutralized because the acid and base no longer exist. (b) The corrosive properties are unaffected because salt is a corrosive agent. (c) The corrosive properties are doubled because the acid and base are combined in the salt. (d) The corrosive properties remain the same when the salt is mixed into water.Why do we use the pH scale to indicate the acidity of a solution rather than simply stating the concentration of hydronium ions? (a) It includes the concentration of hydronium and hydroxide ions. (b) It is used because the general public understands it. (c) It is more accurate to use the pH scale. (d) It is more convenient, since the concentration of hydronium ions is usually so small.5RATWhen the hydronium ion concentration equals 1M , what is the pH of the solution? Is the solution acidic or basic? (a) pH=0 ; this is an acidic solution. (b) pH=1 ; this is an acidic solution. (c) pH=10 ; this is a basic solution. (d) pH=7 ; this is a neutral solution.What element is oxidized in the following equation and what element is reduced? Sn2++2AgSn+2Ag+ (a) The tin ion, Sn2+ , is oxidized, while the silver, Ag , is reduced. (b) The tin ion, Sn2+ , is reduced while the silver, Ag , is oxidized. (c) Both the tin ion, Sn2+ , and the silver, Ag , are reduced. (d) Bob the tin ion, Sn2+ , and the silver, Ag , are oxidized.What is the purpose of the salt bridge in Figure 21.17? (a) To prevent any further migration of electrons through the wire. (b) To allow for the build-up of positively charged ions in one container and negatively charged ions in the other container. (c) To allow the Fe2+ and the Cu2+ to flow freely between the two containers. (d) To allow for a balance of charge between the two chambers.Why does a battery that has thick zinc walls last longer than one that has thin zinc walls? (a) Thick zinc walls prevent the battery from overheating. (b) Thicker zinc walls prevent electrons from being lost into the surrounding environment. (c) Thicker zinc walls last longer at holding in the battery acid. (d) The zinc walls are transformed into zinc ions as the battery provides electricity.How does an atoms electronegativity relate to its ability to act as an oxidizing agent? (a) The greater the electronegativity of an atom, the greater its ability to act as an oxidising agent. (b) The lower the electronegativity of an atom, the lower its ability to act an oxidizing agent. (c) The greater the electronegativity of an atom, the lower its ability to act as an oxidizing agent. (d) Electronegativity does not affect the atoms ability to act as an oxidizing agent.What are some uses of hydrocarbons?How do two structural isomers differ from each other?How are two structural isomers similar to each other?What physical property of hydrocarbons is used in fractional distillation?To how many atoms is a saturated carbon atom bonded?What is the difference between a saturated hydrocarbon and an unsaturated hydrocarbon?How many multiple bonds must a hydrocarbon have in order to be classified as unsaturated?Aromatic compounds contain what kind of ring?What is a heteroatom?Which heteroatom is characteristic of an alcohol?Why are low formula mass alcohols soluble in water?What distinguishes an alcohol from an ether?Which heteroatom is characteristic of an amine?Do amines tend to be acidic, neutral, or basic?Are alkaloids found in nature?Which elements make up the carbonyl group?How are ketones and aldehydes related to each other? How are they different from each other?How are amides and carboxylic acids related to each other? How are they different from each other?What happens to the double bond of a monomer participating in the formation of an addition polymer?What is released in the formation of a condensation polymer?Rank the following hydrocarbons in order of increasing number of hydrogens:2TCRank the following molecule in order of the increasing solubility in water.Rank the following organic molecules in order of increasing solubility in water:What property of carbon allows for the formation of so many different organic molecules?2TEHydrocarbons release a lot of energy when ignited. Where does this energy comes from?