Question: How does the Bohr theory account for

> Using the average atomic masses given inside the front cover of this book, calculate the indicated quantities. a. the mass in grams of 125 iron atoms b. the mass in amu of 125 iron atoms c. the number of moles of iron atoms in 125 g of iron d. the ma

> Using the symbol of the previous noble gas to indicate the core electrons, write the electron configuration for each of the following elements. a. arsenic, Z = 33 b. titanium, Z = 22 c. strontium, Z = 38 d. chlorine, Z = 17

> Would you expect the valence electrons of rubidium and strontium to reside in the 5s or the 4d orbitals? Why?

> Why do we believe that the valence electrons of calcium and potassium reside in the 4s orbital rather than in the 3d orbital?

> For each of the following, give an atom and its complete electron configuration that would be expected to have the indicated number of valence electrons. a. two b. four c. six d. eight

> The “Chemistry in Focus” segment A Magnetic Moment discusses the ability to levitate a frog in a magnetic field because electrons, when sensing a strong magnetic field, respond by opposing it. This is called diamagnetism. Atoms that are diamagnetic have

> Write the complete orbital diagram for each of the following elements, using boxes to represent orbitals and arrows to represent electrons. a. aluminum, Z = 13 b. phosphorus, Z = 15 c. bromine, Z = 35 d. argon, Z = 18

> To which element does each of the following electron configurations correspond? a. 1s22s22p63s23p64s23d104p4 b. 1s22s22p63s23p64s23d1 c. 1s22s22p63s23p4 d. 1s22s22p63s23p64s23d104p65s24d105p5

> Write the full electron configuration (1s22s2, etc.) for each of the following elements. a. phosphorus, Z = 15 b. calcium, Z = 20 c. potassium, Z = 19 d. boron, Z = 5

> To which element does each of the following electron configurations correspond? a. 1s22s22p63s23p2 b. 1s22s2 c. 1s22s22p6 d. 1s22s22p63s23p6

> What does the wavelength of electromagnetic radiation represent? How is the wavelength of radiation related to the energy of the photons of the radiation?

> Using the average atomic masses given inside the front cover of this book, calculate the number of atoms present in each of the following samples. a. 1.50 g of silver, Ag b. 0.0015 mole of copper, Cu c. 0.0015 g of copper, Cu d. 2.00 kg of magnesium,

> Write the full electron configuration (1s22s2, etc.) for each of the following elements. a. magnesium, Z = 12 b. lithium, Z = 3 c. oxygen, Z = 8 d. sulfur, Z = 16

> How are the electron arrangements in a given group (vertical column) of the periodic table related? How is this relationship manifested in the properties of the elements in the given group?

> When a hydrogen atom is in its ground state, in which orbital is its electron found? Why?

> Which orbital is the first to be filled in any atom? Why?

> Which of the following orbital designations is(are) not possible? a. 3f b. 5s c. 4d d. 1p

> Which of the following orbital designations is(are) possible? a. 1s b. 2p c. 2d d. 4f

> According to the Pauli exclusion principle, the electrons within a given orbital must have spins.

> According to the Pauli exclusion principle, a given orbital can contain only electrons.

> The number of sublevels in a principal energy level (increases/ decreases) as n increases.

> How does the energy of a principal energy level depend on the value of n? Does a higher value of n mean a higher or lower energy?

> Use the average atomic masses given inside the front cover of this book to calculate the mass in grams of each of the following samples. a. 0.00552 mole of calcium b. 6.25 mmol of boron (1 mmol = 1⁄1000 mole) c. 135 moles of aluminum d. 1.34 * 10-7 m

> Why can only two electrons occupy a particular orbital? What is this idea called?

> When describing the electrons in an orbital, we use arrows pointing upward and downward / to indicate what property?

> Why do we believe that the three electrons in the 2p sublevel of nitrogen occupy different orbitals?

> Answer each of the following questions. Be thorough in your answers, and provide complete support. a. Write the ground-state electron configuration for oxygen. b. Draw the orbital diagram for the ground state of oxygen. Justify your placement of elect

> Which of the following statements is(are) true regarding the atom? a. Negatively charged particles are embedded in a positively charged cloud throughout the atom. b. As verified by Rutherford, only positively charged particles called protons are found

> In the text (Section 11.6) it was mentioned that current theories of atomic structure suggest that all matter and all energy demonstrate both particle-like and wave-like properties under the appropriate conditions, although the wave-like nature of matter

> Without referring to your textbook or a periodic table, write the full electron configuration, the orbital box diagram, and the noble gas shorthand configuration for the elements with the following atomic numbers. a. Z = 21 b. Z = 15 c. Z = 36 d. Z = 3

> Without referring to your textbook or a periodic table, write the full electron configuration, the orbital box diagram, and the noble gas shorthand configuration for the elements with the following atomic numbers. a. Z = 19 b. Z = 22 c. Z = 14 d. Z =

> One bit of evidence that the present theory of atomic structure is “correct” lies in the magnetic properties of matter. Atoms with unpaired electrons are attracted by magnetic fields and thus are said to exhibit paramagnetism. The degree to which this ef

> An unknown element is a nonmetal and has a valence-electron configuration of ns2np4. a. How many valence electrons does this element have? b. Possible identities for this element include which of the following? Cl, S, Pb, Se, Cr

> Use the average atomic masses given inside the front cover of this book to calculate the mass in grams of each of the following samples. a. 0.251 mole of lithium b. 1.51 moles of aluminum c. 8.75 * 10-2 moles of lead d. 125 moles of chromium e. 4.25

> Arrange the following sets of elements in order of increasing atomic size. a. Sn, Xe, Rb, Sr b. Rn, He, Xe, Kr c. Pb, Ba, Cs, At

> In each of the following groups, which element is least reactive? a. Group 1 b. Group 7 c. Group 2 d. Group 6

> The “Chemistry in Focus” segment Fireworks discusses some of the chemicals that give rise to the colors of fireworks. How do these colors support the existence of quantized energy levels in atoms?

> Where are the most nonmetallic elements located on the periodic table? Why do these elements pull electrons from metallic elements so effectively during a reaction?

> Give some similarities that exist among the elements of Group 1.

> What are some of the physical properties that distinguish the metallic elements from the nonmetals? Are these properties absolute, or do some nonmetallic elements exhibit some metallic properties (and vice versa)?

> Write the complete orbital diagram for each of the following elements, using boxes to represent orbitals and arrows to represent electrons. a. helium, Z = 2 b. neon, Z = 10 c. krypton, Z = 36 d. xenon, Z = 54

> Where are the valence electrons found in an atom, and why are these particular electrons most important to the chemical properties of the atom?

> Although a hydrogen atom has only one electron, the hydrogen atom possesses a complete set of available orbitals. What purpose do these additional orbitals serve?

> What overall shape do the 2p and 3p orbitals have? How do the 2p orbitals differ from the 3p orbitals? How are they similar?

> Use the average atomic masses given inside the front cover of this book to calculate the number of moles of the element present in each of the following samples. a. 49.2 g of sulfur b. 7.44 * 104 kg of lead c. 3.27 mg of chlorine d. 4.01 g of lithium

> The “Chemistry in Focus” segment Plastic That Talks and Listens! discusses polyvinylidene difluoride (PVDF). What is the empirical formula of PVDF? Note: An empirical formula is the simplest whole-number ratio of atoms in a compound. This is discussed mo

> Your text describes the probability map for an s orbital using an analogy to the earth’s atmosphere. Explain this analogy.

> Section 11.6 uses a “firefly” analogy to illustrate how the wave mechanical model for the atom differs from Bohr’s model. Explain this analogy.

> What major assumption (that was analogous to what had already been demonstrated for electromagnetic radiation) did de Broglie and Schrödinger make about the motion of tiny particles?

> What does it mean to say that the hydrogen atom has discrete energy levels? How is this fact reflected in the radiation that excited hydrogen atoms emit?

> Describe briefly why the study of electromagnetic radiation has been important to our understanding of the arrangement of electrons in atoms.

> The “Chemistry in Focus” segment Atmospheric Effects discusses the greenhouse effect. How do the greenhouse gases CO2, H2O, and CH4 have an effect on the temperature of the atmosphere?

> Calculate ∆H for the reaction N2H4(l) + O2(g) N2(g) + 2H2O(l) given the following data: Equation ΔH (kI) 2NH3(g) + 3N,0(g) 4N2(g) + 3H,0(/) - 1010 N,0(g) + 3H2(g) → N2Hạ(/) + H20(1) 2NH3(g) + }02(g)→ N2Ha(/

> A swimming pool, 10.0 m by 4.0 m, is filled with water to a depth of 3.0 m at a temperature of 20.2 °C. How much energy is required to raise the temperature of the water to 24.6 °C?

> Which of the following reactions is/are endothermic? a. CO2(s) CO2(g) b. NH3(g) NH3(l) c. 2H2(g) + O2(g) 2H2O(g) d. H2O(l) H2O(s) e. Cl2(g) 2Cl(g)

> Use the average atomic masses given inside the front cover of this book to calculate the number of moles of the element present in each of the following samples. a. 4.95 g of neon b. 72.5 g of nickel c. 115 mg of silver d. 6.22 µg of uranium (µ is a

> It has been determined that the body can generate 5500 kJ of energy during one hour of strenuous exercise. Perspiration is the body’s mechanism for eliminating this heat. How many grams and how many liters of water would have to be evaporated through per

> Consider the following equations: 3A + 6B 3D ∆H = -403 kJ/mol E + 2F A ∆H = -105.2 kJ/mol C E + 3D ∆H = +64.8 kJ/mol Suppose the first equation is reversed and multiplied by 1/6 , the second and third equati

> The overall reaction in commercial heat packs can be represented as 4Fe(s) + 3O2(g) 2Fe2O3(s) ∆H = -1652 kJ a. How much heat is released when 4.00 moles of iron is reacted with excess O2? b. How much heat is released when 1.00 mole

> For each of the substances listed in Table 10.1, calculate the quantity of heat required to heat 150. g of the substance by 11.2 °C. Table 10.1 The Specific Heat Capacities of Some Common Substances Specific Heat Capacity (J/g °C) Substan

> A 25.0-g sample of pure iron at 85 °C is dropped into 75 g of water at 20. °C. What is the final temperature of the water–iron mixture?

> A 50.0-g sample of water at 100. °C is poured into a 50.0-g sample of water at 25 °C. What will be the final temperature of the water?

> What is the “greenhouse effect”? Why is a certain level of greenhouse gases beneficial, but too high a level dangerous to life on earth? What is the most common greenhouse gas?

> What does petroleum consist of? What are some “fractions” into which petroleum is refined? How are these fractions related to the sizes of the molecules involved?

> Given the following data: C2H2(g) + 5/2O2(g) 2CO2(g) + H2O(l) ∆H = -1300. kJ C(s) + O2(g) CO2(g) ∆H = -394 kJ H2(g) + 1/2O2(g) H2O(l) ∆H = -286 kJ Calculate ∆H for the reaction 2C(s)

> Given the following data: S(s) + 3/2 O2(g) SO3(g) ∆H = -395.2 kJ 2SO2(g) + O2(g) 2SO3(g) ∆H = -198.2 kJ Calculate ∆H for the reaction S(s) + O2(g) SO2(g).

> In Fig. 10.1, what kind of energy does ball A possess initially when at rest at the top of the hill? What kind of energies are involved as ball A moves down the hill? What kind of energy does ball A possess when it reaches the bottom of the hill and stop

> Given the following data: C(s) + O2(g) CO2(g) ∆H = -393 kJ 2CO(g) + O2(g) 2CO2(g) ∆H = -566 kJ Calculate ∆H for the reaction 2C(s) + O2(g) CO(g).

> Given the following hypothetical data: X(g) + Y(g) XY(g) for which ∆H = a kJ X(g) + Z(g) XZ(g) for which ∆H = b kJ Calculate ∆H for the reaction Y(g) + XZ(g) XY(g) + Z(g)

> When ethanol (grain alcohol, C2H5OH) is burned in oxygen, approximately 1360 kJ of heat energy is released per mole of ethanol. C2H5OH(l) + 3O2(g) 2CO2(g) + 3H2O(g) a. What quantity of heat is released for each gram of ethanol

> For the reaction S(s) + O2(g) SO2(g), ∆H = -296 kJ per mole of SO2 formed. a. Calculate the quantity of heat released when 1.00 g of sulfur is burned in oxygen. b. Calculate the quantity of heat released when 0.501 mole of sulfur is b

> The enthalpy change for the reaction of hydrogen gas with fluorine gas to produce hydrogen fluoride is 2542 kJ for the equation as written: H2(g) + F2(g) 2HF(g) ∆H = -542 kJ a. What is the enthalpy change per mole of hydrogen fluorid

> The “Chemistry in Focus” segment Nature Has Hot Plants discusses thermogenic, or heat-producing, plants. For some plants, enough heat is generated to increase the temperature of the blossom by 15 °C. About how much heat is required to increase the temper

> Convert the following numbers of calories or kilocalories into joules or kilojoules. a. 7845 cal b. 4.55 * 104 cal c. 62.142 kcal d. 43,024 cal

> How is the calorie defined? How does a Calorie differ from a calorie? How is the joule related to the calorie?

> How are the temperature of an object and the thermal energy of an object related?

> The production capacity for acrylonitrile (C3H3N) in the United States is over 2 billion pounds per year. Acrylonitrile, the building block for polyacrylonitrile fibers and a variety of plastics, is produced from gaseous propylene, ammonia, and oxygen:

> What is meant by a state function? Give an example.

> Sulfur dioxide gas reacts with sodium hydroxide to form sodium sulfite and water. The unbalanced chemical equation for this reaction is as follows: SO2(g) + NaOH(s) Na2SO3(s) + H2O(l) Assuming you react 38.3 g of sulfur dioxide with

> Ammonia gas reacts with sodium metal to form sodium amide (NaNH2) and hydrogen gas. The unbalanced chemical equation for this reaction is as follows: NH3(g) + Na(s) NaNH2(s) + H2(g) Assuming that you start with 32.8 g of ammonia

> Over the years, the thermite reaction has been used for welding railroad rails, in incendiary bombs, and to ignite solid fuel rocket motors. The reaction is Fe2O3(s) + 2Al(s) / 2Fe(l) + Al2O3(s) a. What mass of iron(III) oxide must be used to produce 25

> Consider the following reaction: 4NH3(g) + 5O2(g) ( 4NO(g) + 6H2O(g) a. If a container were to have only 10 molecules of O2(g) and 10 molecules of NH3(g), how many total molecules (reactant and product) would be present in the container after the above

> Hydrazine, N2H4, emits a large quantity of energy when it reacts with oxygen, which has led to hydrazine’s use as a fuel for rockets: N2H4(l) + O2(g) / N2(g) + 2H2O(g) How many moles of each of the gaseous products are produced when 20.0 g of pure hydra

> For each of the following unbalanced chemical equations, suppose 25.0 g of each reactant is taken. Show by calculation which reactant is limiting. Calculate the theoretical yield in grams of the product in boldface. a. C2H5OH(l) + O2(g)

> For each of the following unbalanced chemical equations, suppose exactly 5.0 g of each reactant is taken. Determine which reactant is limiting, and calculate what mass of each product is expected, assuming that the limiting reactant is completely consume

> The gaseous hydrocarbon acetylene, C2H2, is used in welders’ torches because of the large amount of heat released when acetylene burns with oxygen. 2C2H2(g) + 5O2(g) / 4CO2(g) + 2H2O(g) How many grams of oxygen gas are needed for the complete combustion

> When small quantities of elemental hydrogen gas are needed for laboratory work, the hydrogen is often generated by chemical reaction of a metal with acid. For example, zinc reacts with hydrochloric acid, releasing gaseous elemental hydrogen: Zn(s) + 2HC

> When elemental copper is placed in a solution of silver nitrate, the following oxidation–reduction reaction takes place, forming elemental silver: Cu(s) + 2AgNO3(aq) / Cu(NO3)2(aq) + 2Ag(s) What mass of copper is required to remove all the silver from a

> For each of the following unbalanced equations, indicate how many moles of the first product are produced if 0.625 mole of the second product forms. State clearly the mole ratio used for each conversion. a. KO2(s) + H2O(l) O2(g

> Many metals occur naturally as sulfide compounds; examples include ZnS and CoS. Air pollution often accompanies the processing of these ores, because toxic sulfur dioxide is released as the ore is converted from the sulfide to the oxide by roasting (smel

> One step in the commercial production of sulfuric acid, H2SO4, involves the conversion of sulfur dioxide, SO2, into sulfur trioxide, SO3. 2SO2(g) + O2(g) / 2SO3(g) If 150 kg of SO2 reacts completely, what mass of SO3 should result?

> For each of the following incomplete and unbalanced equations, indicate how many moles of the second reactant would be required to react completely with 0.145 mole of the first reactant. a. BaCl2(aq) + H2SO4(aq) b. AgNO3(aq) + NaCl(aq) c. Pb(NO3)2(aq

> Using the average atomic masses given inside the front cover of the text, calculate the mass in grams of each of the following samples. a. 5.0 moles of nitric acid b. 0.000305 mole of mercury c. 2.31 * 10-5 mole of potassium chromate d. 10.5 moles of

> For each of the following balanced equations, indicate how many moles of the product could be produced by complete reaction of 1.00 g of the reactant indicated in boldface. Indicate clearly the mole ratio used for the conversion. a. NH3(g) + HCl(g) / NH

> For each of the following balanced reactions, calculate how many moles of each product would be produced by complete conversion of 0.50 mole of the reactant indicated in boldface. Indicate clearly the mole ratio used for the conversion. a. 2H2O2(l) / 2H

> For each of the following reactions, give the balanced equation for the reaction and state the meaning of the equation in terms of numbers of individual molecules and in terms of moles of molecules. a. UO2(s) + 4HF(aq) / UF4(aq) + 2H2O(l) b. 2NaC2H3O2(a

> The traditional method of analysis for the amount of chloride ion present in a sample is to dissolve the sample in water and then slowly to add a solution of silver nitrate. Silver chloride is very insoluble in water, and by adding a slight excess of sil

> Barium chloride solutions are used in chemical analysis for the quantitative precipitation of sulfate ion from solution. Ba2+(aq) + SO42–(aq) / BaSO4(s) Suppose a solution is known to contain on the order of 150 mg of sulfate ion. What mass of barium c

> When elemental copper is strongly heated with sulfur, a mixture of CuS and Cu2S is produced, with CuS predominating. Cu(s) + S(s) / CuS(s) 2Cu(s) + S(s) / Cu2S(s) What is the theoretical yield of CuS when 31.8 g of Cu(s) is heated with 50.0 g of

> For each of the following unbalanced equations, indicate how many moles of the second reactant would be required to react exactly with 0.275 mole of the first reactant. State clearly the mole ratio used for the conversion. a. Cl2(g) + KI(aq)