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Ordered according to coverage: Chapter 1 2 6 7 8 Organic 3 9 10 18 11 4 13 Reactions 5 15 Answer key page 21 21 24 26 28 30 22 32 35 44 37 23 40 45 23 42 53 SUPPLEMENTAL PROBLEMS FOR CHEM 110 Ordered by chapter number: Chapter 1 2 3 4 5 6 7 8 Organic 9 10 11 13 15 18 Reactions Answer key The problems are divided into chapters matching the book’s chapter numbers, and the chapters are arranged in order in which they are covered in lectures (see the syllabus). 19 page 21 21 22 23 23 24 26 28 30 32 34 37 40 42 44 45 53 20 Chapter 1 Chapter 2 1. 1. 13.2 nm is equal to A. B. C. D. E. 2. − A. 23% B. 91% C. 77% D. 45% E. None of the above is within 10% of the correct answer − − 2. 0.908 g/mL 1.10 g/mL 0.21 g/mL Not determinable from the information given None of the above answers is correct A. B. C. D. E. (1.025)(1.63)(94.0 + 18.13 ! 4.6) = 20.12949552 3. 8.925 to the correct number of significant figures is 4. 2 − 3 2 1.9 × 10 2 1.97 × 10 2 2.0 × 10 0.02 None of the above answers is correct − 4. − ? p=8, n=9, e=10 p=8, n=9, e=8 p=8, n=9, e=6 p=9, n=8, e=11 p=9, n=8, e=9 X and Y are two species, each consisting of one nucleus and a number of electrons. The two species are found to contain the same number of protons, the same number of neutrons, and different numbers of electrons. Which of the following statements about X and Y is correct? Which of the following chemical formulas is NOT the expected one for the compound named? − 5 (107.36 – 99.2) (5.4033 × 10 ) = 4.4090928 × 10 A. B. C. D. E. 6 The above calculation, when expressed to the correct number of significant figures and properly rounded, should be written A. B. C. D. E. 17 2− 8O A. X and Y are both neutral atoms. B. X and Y are isotopes of one another. C. The two have different atomic numbers. D. At least one of the species is an ion. E. There is no correct answer above since A⎯D are all incorrect. The result of adding 1.17 × 10 and 8 × 10 is, to the correct number of significant figures A. B. C. D. E. 5. 20 1 2.01 × 10 1 2.0 × 10 20.13 1 2.012 × 10 − How many protons, neutrons and electrons are present in The answer to the calculation A. B. C. D. E. 35 − A 112.6 g mass of unknown material is submersed in 102 mL of water to yield a final volume of 126 mL. The apparent density of the unknown material is A. B. C. D. E. 3. 6 1.32 × 10 cm 6 1.32 × 10 mm 8 1.32 × 10 cm 8 1.32 × 10 mm None of the above answers is correct 37 Chlorine exists primarily as Cl and Cl and has an average atomic weight of 35.453. The abundance of Cl with atomic weight of 35 is 6 4.4 × 10 6 4.40 × 10 6 4.41 × 10 6 4.4090 × 10 6 4.4091 × 10 21 Ga2O3 – gallium oxide AlCl3 – aluminum chloride Li2O – lithium oxide MgBr – magnesium bromide SrI2 – strontium iodide Chapter 2 continued 5. Which of the following formula–name combinations is(are) correct? 1. 2. 3. NH4Cl2 K2CO3 Ca3(PO4)2 5. A. B. C. D. E. ammonium chloride potassium carbonate calcium phosphate The correct combination(s) is(are) A. 1 only B. 2 only C. 1 and 3 only D. 2 and 3 only E. 1 and 2 only 6. The molecular weight of ethylene glycol, C2H6O2, is A. B. C. D. E. 2. One gram of alum, KAl(SO4)2 12H2O, has 1.3 × 10 Al atoms. How many oxygen atoms are present in 1.0 g of alum? A. B. C. D. E. 3. 7. The percent mass of hydrogen in the following compound is A. 5.2% B. 7.8% C. 8.7% D. 7.2% E. 8.4% 21 H2 C O H2C CH3 CH N O H CH3 H H 22 1.3 × 10 22 2.6 × 10 22 1.6 × 10 22 1.0 × 10 22 2.1 × 10 8. The carbon backbone for a molecule is given below. What is the molecular weight of this compound? A . 114 g/mol B . 115 g/mol C . 119 g/mol D . 120 g/mol E . 126 g/mol 63% 20% 43% 78% None of the above is correct to within 5%. 9. What is the empirical formula of a hydrocarbon containing 84.2% C and 15.8% H by weight? A. B. C. D. E. N Cl P Br I H What is the weight percent of silver in silver nitrate, AgNO3? A. B. C. D. E. 4. 29 g/mole 34 g/mole 62 g/mole 94 g/mole 46 g/mole 0.1 moles of P4O10 0.2 moles of P4O6 0.3 moles of N2O5 0.4 moles of N2O4 0.5 moles of BiF3 “X” is an unknown element which forms an acid, HXO3. The mass of 0.0133 mol of this acid is 1.123g. Find the atomic mass of X and identify the element represented by X. The element X is A. B. C. D. E. Chapter 3 1. Which of the following samples contains the largest total number of atoms? C8H18 C16H3 C 3H 8 C5H12 C 4H 9 A Chem 110 TA synthesizes a compound composed of carbon, hydrogen, and nitrogen and submits 0.1156 g of it to combustion analysis. The TA recovers 0.3556 g of carbon dioxide and 0.0655 g of water. What is the empirical formula of the compound? A. B. C. D. E. 22 C11H11 C20H18N2 C 5H 5N C10H18 C10H9N Chapter 4 Chapter 5 1. 1. Which of the following aqueous solutions would you expect to be the best conductor of electric current? A. B. C. D. E. 2. 1.0 M sugar (C6H12O6) 1.0 M CaCl2 1.0 M ethanol (C2H5OH) 1.0 M acetic acid (HC2H3O2) 1.0 M NH4OH A. B. C. D. E. 3. A. B. C. D. E. CH3COOH (HC2H3O2) CH3COONa C6H12O11 (table sugar) NaClO4 2. 1 and 2 are weak electrolytes 1 and 3 are weak electrolytes 1, 2 and 3 are weak electrolytes 4 is the only weak electrolyte 1 is the only weak electrolyte Given the following reactions and their enthalpy changes 2 C2H2(g) + 5 O2(g) → 4 CO2(g) + 2 H2O(l) C(s) + O2(g) → CO2(g) ΔHRXN = –2599.2 kJ 2 H2(g) + O2(g) → 2 H2O(l) ΔHRXN = –571.8 kJ A. B. C. D. E. 1.1 L 910 mL 90 mL 540 mL 3.9 L ΔHRXN = –393.5 kJ 620.2 kJ −620.2 kJ −453.4 kJ 226.7 kJ None of the above is within 10% of the correct answer 3. Substance SO2(g) SO3(g) SO2Cl2(g) H2SO4((l) H2O((l) 1.61 mL 7.73 mL 17.2 mL 41.5 mL 51.5 mL ΔH° f (kJ/mol) −297 −396 −364 −814 −286 The value of ΔH° for the following reaction is –62.1 kJ. What is the value of ΔH°f (in kJ/mol) for HCl(g)? A 24.00 mL sample of a solution of Pb(ClO3)2 was diluted with water to 52.00 mL. A 17.00 mL sample of – the dilute solution was found to contain 0.220 M ClO3 (aq). What was the concentration of Pb(ClO3)2 in the original undiluted solution? A. B. C. D. E. ΔH = +189 kJ ΔH = −4.97 kJ ΔH = +388 kJ ΔH = −194 kJ None of the above is within 1% of the correct answer Calculate ΔH°f for acetylene, C2H2(g). How many milliliters of a 132.00 mL solution of 1.98 M AlCl3 must be used to make 162.00 mL of a – solution that has a concentration of 0.630 M Cl (aq)? A. B. C. D. E. 5. the enthalpy of reaction (per mole of H2 produced) is How much 0.154 M NaCl, “physiological saline,” can be prepared by dilution of 100 mL of a 6.0 M NaCl solution? A. B. C. D. E. 4. 2 K(s) + 2 H2O(l) → 2 KOH(aq) + H2(g) Which of the following are weak electrolytes? 1. 2. 3. 4. It is found that 6.00 g of potassium metal reacts with excess water to release 29.8 kJ of heat. This means that, for the reaction SO2Cl2(g) + 2 H2O(l) → H2SO4(l) + 2 HCl(g) A. B. C. D. E. –2 3.60 × 10 M –2 7.19 × 10 M 0.238 M 0.156 M 0.477 M 23 −184 −372 −1079 30 −92 Chapter 5 continued Chapter 6 4. 1. For which one of the following equations is ΔH°rxn equal to ΔH°f for the product? A. B. C. D. E. 5. Xe(g) + 2F2(g) → XeF4(g) CH4(g) + 2Cl2(g) → CH2Cl2(ℓ) + 2 HCl(g) N2(g) + O3(g) → N2O3(g) 2 CO(g) + O2(g) → 2 CO2(g) None of the above have ΔH°rxn equal to ΔH°f 2. −367.6 kJ −183.8 kJ −667.4 kJ not determinable from the data given None of the above answers is correct The reaction is exothermic with ΔH = −46.2 kJ. The reaction is endothermic with ΔH = −92.4 kJ. The reaction is exothermic with ΔH = 92.4 kJ. The reaction is endothermic with ΔH = 92.4 kJ. The reaction is endothermic with ΔH = 46.2 kJ. − − − 14 5.81 × 10 J 19 3.85 × 10 J 27 1.28 × 10 J 36 4.29 × 10 J 44 1.43 × 10 J − − − − 4. Which photon has an energy that is greater than the energy of a blue photon? A. B. C. D. E. 0.0100 mole of dry, solid KClO3 is added to 50.0 g of water at 20.10°C in a coffee–cup calorimeter. The temperature is observed to drop to 18.10°C. ΔH of hydration for one mole of KClO3 is (within 2%) [Heat capacity of water = 4.18 J/°C g] A. B. C. D. E. 27 1.29 × 10 J 16 1.99 × 10 J 10 1.21 × 10 J 8 1.21 × 10 J 10 3.34 × 10 J Green light of wavelength 516 nm is absorbed by an atomic gas. What is the energy difference between the two quantum states involved in the transition? A. B. C. D. E. 2 NH3(g) → 3 H2(g) + N2(g) 7. What is the energy possessed by one mole of x–ray photons if the wavelength of the x–ray is 1.00 × 9 10 m? A. B. C. D. E. The standard heat of formation of ammonia, NH3(g), is –46.2 kJ/mole. Which of the following is true about the reaction: A. B. C. D. E. 7.25 × 10 km 7 2.99 × 10 km 4 2.99 × 10 km 3.02 km none of these − 3. 6. 3 A. B. C. D. E. The standard heat of formation for H2O(g) is –241.8 kJ/mol, and for NaOH(s) it is –425.6 kJ/mol. The enthalpy change for the reaction between Na(s) and H2O(g) to produce NaOH(s) and H2(g) is, per mole of H2(g) produced, A. B. C. D. E. A radio station broadcasts on a frequency of 99.5 kilocycles/s. What is the wavelength of this radiation in km? –0.836 kJ 0.836 kJ –42.8 kJ 42.8 kJ None of the above answers is correct. 5. A He-Ne laser (λ = 633nm) is used to heat up a sample. How many photons are needed to transfer 12 J of heat to the sample? A. B. C. D. E. 24 microwave photon radio photon green photon infrared photon ultraviolet photon 19 3.8 × 10 12,000 11 6.3 × 10 19 3.2 × 10 6 1.6 × 10 − Chapter 6 continued 6. If the Bohr model is used, what frequency of light would be required for ionization of hydrogen? 14 A. B. C. D. E. 7. 6.17 × 10 Hz 3 1.31 × 10 Hz 15 3.29 × 10 Hz 10 4.31 × 10 Hz None of the above is within 5% of the correct answer 2. 3. A. B. C. D. E. The radius of the orbit increases as the principal quantum number increases. The energy required to ionize the atom increases as the principal quantum number decreases. Light emitted by the excited hydrogen atom corresponds to transitions from orbits of higher principal quantum number to lower principal quantum number. A. B. C. D. E. 1s 2s A. (⇅) (⇅) (⇅) (↑) B. (⇅) (⇅) (⇅) (⇅) (⇅) (↑) C. (⇅) (⇅) D. (⇅) (⇅) (⇅) (⇅) ( ) (⇅) (⇅) (⇅) (⇅) E. (⇅) (⇅) (↑) For electron distributions, which of the following statements are true? A. B. C. D. E. 3 9 15 5 None of the above 2p 3s (↑) (↑) (↑) 13. Which of the following ground state electron configurations can be ruled out by the Pauli Exclusion Principle? n = 3 to n = 4 n = 1 to n = 3 n = 6 to n = 4 n = 7 to n = 5 n = 2 to n = 5 3. mℓ 0 1 0 0 12. Which of the following could not be an orbital diagram for an atom in its ground state? 1 only 1and 2 only 2 and 3 only 1 and 3 only 1, 2, and 3 1. 2. n ℓ 4 3 3 0 4 1 4 0 None of these 11. An atom of phosphorus 15P has how many electrons with quantum number ℓ = 1? Which of the following electron transitions in a hydrogen atom results in the greatest release of energy from the atom? A. B. C. D. E. 9. A. B. C. D. E. Which of the following statements are true for the Bohr model of the hydrogen atom? 1. 8. 10. Which series of quantum numbers describes the orbital in which the highest energy electron in potassium resides in the ground state? d orbitals have a spherical shape. p orbitals have a high electron density at the nucleus. s orbitals have no electron density at the nucleus. A. B. C. D. E. 1 and 2 2 only 2 and 3 3 only None of the statements is true 25 1. 1s 3 2s 2 2p 5 2. 1s 2 2s 2 2p 7 3s 2 3. 1s 2 2s 2 2p 6 3s 2 3p 6 4. 1s 2 2s 2 2p 6 3s 2 3p 6 1 only 1 and 3 only 1, 2, and 3 only 1, 2, 3, and 4 only 1 and 4 only 4s 2 3d 12 Chapter 6 continued Chapter 7 14. In the ground state electronic configuration of Cr, how many total shells, subshells and orbitals contain at least one electron, and how many unpaired electrons are present? 1. Shells Subshells Orbitals A. Elements D and G should form a compound which is a gas at room temperature and which has formula GD. B. Elements D and G should form a compound which is a solid at room temperature with formula GD. C. Elements D and G should not react with each other. D. Elements D and G should react to form a covalent compound with formula DG7. E. None of the above is a true statement. Unpaired Electrons A. 4 3 8 4 B. 4 7 15 6 C. 4 7 15 4 D. 4 7 14 4 E. 4 7 14 6 Elements D, E, and G have atomic numbers Z, Z+1, and Z+2 respectively. E is a noble gas (not helium). Which statement is true? 2. 15. Which orbital diagram(s) represents an excited state electron configuration of C? Atom X is in Group IIA and atom Y is in Group VIIA. A compound formed between these two elements would have the formula A. B. C. D. E. i. X 2Y XY2 X 2Y 7 X 7Y 2 None of the above ii. 3. Which of the following has the configuration of a noble gas? A. B. C. D. E. i only iii only ii and iii i and iii i, ii and iii A. B. C. D. E. 16. When light of wavelength 420 nm is focused on a metal surface, electrons are ejected with a speed of 5 7.00 × 10 m/sec. The binding energy of a mole of electrons to the metal is A. B. C. D. E. 2+ 1. 2. 3. iii. 4. 4 26 − 1 only 2 only 1 and 2 2 and 3 1 and 3 The species which may not have the electron 2 2 6 2 6 1 1 configuration 1s 2s 2p 3s 3p 4s 4d is A. B. C. D. E. 8.22 × 10 J/mole 5 1.50 × 10 J/mole 2 2.72 × 10 J/mole 1 5.63 × 10 J/mole None of the above is correct to within 5% S Br 4+ Si 2+ Sc + Sc Ca 1 K 2+ Ti − Chapter 7 continued 5. 9. Which of the following is a true statement? 2 2 − 7. C. A valence electron in O Cl(g) Cl (g) Cl(g) + e Cl(g) + e Cl(g) − − − → → → → → + Cl (g) + e Cl(g) + e + Cl (g) Cl (g) Cl (g) + e A. B. C. D. E. − − − A. B. C. D. E. 3+ 1 2 3 4 5 A. 1s ⇅ 2s ⇅ 2p ⇅ ↑ ↑ B. 1s ⇅ 2s ⇅ 2p ⇅ ⇅ ↑ C. 1s ⇅ 2s ⇅ 2p ⇅ ↑ _ D. 1s ⇅ 2s ⇅ 2p ↑ ↑ ↑ E. 1s ⇅ 2s ⇅ 3s ⇅ 4s ⇅ 12. Which of the following gives the correct relationships among the first ionization energies of the elements? Pick the pair that has the lowest (easiest to ionize) ionization energy and the most endothermic (most difficult to attach an electron) electron affinity. Lowest I.E. Cs O Na Na Cs experiences the least 11. A correct orbital diagram for the ground state of the + O ion is 2+ The ionization energy for Li is expected to be greater than that for H because: A. Lithium is a metal whereas hydrogen is not. B. The nuclear charge in lithium is greater than the nuclear charge in hydrogen. 2+ C. The size of the Li ion is greater than the size of the H atom. D. The principal quantum number of the electron is 2+ greater in Li than in H. E. The nucleus of the hydrogen atom has no neutrons. 8. 2– 10. How many unpaired electrons are there in the Fe ion when it is in its ground state? − − – effective nuclear charge. D. All three species have a filled quantum level n = 2. – E. F has the smallest radius. The electron affinity of the chlorine atom is the energy change which occurs in the reaction A. B. C. D. E. 2− A. The series is isoelectronic. + B. Na has the greatest ionization energy (for forming 2+ Na ). 4 A. The configuration 1s 2s 2p is the electronic 2 configuration of O . 2 2 3 B. The ground state for the configuration 1s 2s 2p has one unpaired electron spin. C. Sulfur is the only element in the third period with 2 unpaired electrons in the 3p subshell. 2 D. The configuration [Ar]3d is the configuration for 2+ Ti . E. None of the above is a true statement. 6. + For the series of Na , O , F , which statement is FALSE? 1. 2. 3. 4. Most endothermic E.A. O Na F O Mg A. B. C. D. E. 27 Na Rb Se He > > > > Al > P K > Li S > O Ne > Ar 1 only 2 only 3 only 4 only Both 3 and 4 are correct. Chapter 8 1. Which of the following compounds would have the largest lattice energy? A. B. C. D. E. 2. KF KBr CaO PbS ScN A. C N C N B. C N N C C. N C C N D. E. 6. Which of the following compounds would you expect to possess a multiple bond? A. B. C. D. E. 4. CaO CsI BaS NaF NaCl What is a reasonable Lewis structure for cyanogen, C 2N 2? Which of the following ionic crystals would you expect to have the lowest melting point? A. B. C. D. E. 3. 5. SbH3 AlCl3 CBr4 C 2H 4 SiF4 H C O H 7. C H C O C H C C N A. B. C. D. E. O 8. C 1.25 Å N 2F 4 N 2F 2 N2 N2 N 2F 2 1.45 Å N 2F 2 N 2F 4 N 2F 2 N 2F 4 N2 M: 2.1 Q: 2.4 R: 3.5 In which of the following diatomic molecules would the least polar bond be expected? H H E. 1.10 Å N2 N2 N 2F 4 N 2F 2 N 2F 4 L: 1.1 H D. C The electronegativities of four elements (L, M, Q, and R) are as follows: O H C. N Nitrogen–nitrogen bond lengths of 1.10, 1.25 and 1.45 Å have been measured for different molecules. A. B C. D. E. H B. N Match the molecules N2F2, N2, N2F4 with appropriate N−N bond length. A reasonable Lewis structure for the molecule CH2O is A. N C Which of the following species violates the octet rule? A. B. C. D. E. O H 28 LM MQ QR LR MR GeF4 TeF4 BH4 2 SO4 SiH4 − − Chapter 8 continued 9. 12. Given the following bond energies C−C (348 kJ/mole), C=C (614 kJ/mole), H−H (436 kJ/mole) and the heat of reaction for the following process, estimate the C−H bond energy. Read the following statements: 1. A. B. C. D. E. BF3 and PF5 are examples of violations of the octet rule. 2. BF4 and BF3−NH3 are examples of violations of the octet rule. 3. Expanded valance shells occur most often when the central atom is bonded to a small, electronegative element. 4. The central atoms most capable of having expanded valence shells come from rows 3, 4, and 5 of the periodic table. C 2H 4 + H 2 → C 2H 6 − A. B. C. D. E. ΔH = −137 kJ 420 kJ 283 kJ 525 kJ 350 kJ 645 kJ 13. Using the bond energy data tabulated below, estimate the enthalpy of formation (per mole) of NH3(g). Bond Only statements 1, 3,and 4 are correct. Only statements 1 and 4 are correct. Only statements 2, 3, and 4 are correct. Only statements 3 and 4 are correct. Only statements 2 and 4 are correct. N≡N(N2) H−H N−H Average bond energy (kJ/mol) 941 436 391 The correct answer (in kJ/mol) is closest to 2− 10. From Lewis structures for SO2 and SO3 , we can predict that A. B. C. D. E. A. SO2 has two different S−O bond lengths, one of 2 which is the same as in SO3 . 2 B. All S−O bonds in SO3 should be weaker than S−O bonds in SO2. 2 C. All S−O bonds in SO3 are the same because there are two Lewis resonance structures for this ion. 2 D. S−O bonds in SO3 should be shorter than those in SO2. E. None of the above predictions follow from the Lewis structures. − − −422 −49 49 204 422 14. Following are some average bond energies (kJ/mol): − − 11. Which of the following is a TRUE statement? A. B. C. D. SeO2 has two equivalent resonance structures. XeF4 obeys the octet rule. The structure NOBr is more stable than ONBr. Because of fluorine’s high electronegativity, the F−F bond is very polar. E. None of the above statements is true. C–H 413 O–H 463 C=C 614 C–C 348 O–O 146 C=O 799 C–O 358 O2 495 Estimate the heat released in the complete combustion of ethylene, H2C=CH2. A. B. C. D. E. 29 683 kJ/mol 802 kJ/mol 1297 kJ/mol 1403 kJ/mol 1792 kJ/mol Organic 3. Which of the following Lewis structures are incorrect? 1. Which of the following are not acceptable structures for C4H10? 1) 2) CH3 H I CH3 CH2 CH2 CH3 H C C N H CH3 CH H H H CH3 H C C H C C C H 4) C H H CH3 II H H H C H C 2. C H : : H III CH3 CH CH2 CH3 H O C C N: H CH3 A. B. C. D. E. H C H H 5) H H CH3 3) H 1 and 2 2 and 3 3 and 4 3 and 5 1, 3 and 5 A. B. C. D. E. I only II only III only I and II I, II and III Which of the following is(are) not correct structure(s) of octane C8H18? 1) 4. Of the structures shown below, which is a structural isomer of n-pentane? H H C H H H H H H C C C C H H C C C H H H H H H H H 2) H H C C H H H H H H H C C C C C H C H H H H H H H C C H C H 3) H H H C H A. B. C. D. E. C H b) C CH2 CH CH3 CH3 CH3 CH CH CH2 CH3 CH3 H H H C CH3 H c) H C a) CH3 CH CH2 CH2 d) CH2 CH2 CH2 CH2 H CH2 H CH2 CH3 H e) CH3 CH2 C CH3 CH3 1 only 3 only 1 and 2 2 and 3 all of these are possible structures for octane 30 CH3 Organic continued 7. 5. Which of the compounds shown below can have a geometrical isomer? CH3 CH2 1. CH3 C C Which one of these molecules is an alcohol? A. B. CH3CCH2CH3 H OH O H O C. CH2CH2CH3 D. CH3 HCCH2CH3 2. CH3 CH2 CH3 CH2 C C CH3 E. H none of these are alcohols 8. Identify the functional groups present in the following structure. CH3 3. H C C H 1. ester 2. ether 3. amine 4. ketone 5. amide CH3 a) 1 only b) 2 only c) 3 only d) 1 and 2 e) 2 and 3 H N O A. 1 and 5 B. 2 and 5 C. 2 and 3 D. 4 and 5 E. 3 and 4 6. Which of the following is/are geometric isomers of the structure below? Br 9. Threonine is a naturally occuring amino acid found in many proteins. What functional groups are present in threonine? C2H5 H3C H OH H O Cl H C C C C OH H H NH2 Br Br Cl 1 CH 3 Cl H3C C2H5 2 H3C Cl a) alcohol, amine, ketone Br C2H5 b) alcohol, amine, ester c) carboxylic acid, alcohol, amide 3 d) alcohol, carboxylic acid, amine e) amide, amine, alcohol A. 1 B. 2 C. 3 D. 1 and 2 E. 1 and 3 31 Chapter 9 1. 4. Which of the following are correct statements about the valence–shell electron–pair repulsion (VSEPR) model of bonding? 1. 2. 3. BeF2 2. 3. CF4 NF3 OF2 What is the correct trend in FMF bond angle? A. BeF2 > BF3 > CF4 > NF3 > OF2 Electron–pair geometry in all cases B. BeF2 = OF2 > CF4 > BF3 = NF3 C. BeF2 = OF2 > BF3 = NF3 > CF4 D. BeF2 > BF3 > OF2 > NF3 > CF4 E. CF4 = NF3 > BeF2 = OF2 LARGEST 1 only 2 only 3 only 1, 2, and 3 None of the above 5. SO2 SO3 2 SO4 NO3 BF3 A. B. C. D. E. − The number of bonding pairs of electrons, non– bonding pairs of electrons and molecular shape of the + H3O ion are Bonding Pairs Non–bonding A. 4 Pairs 0 tetrahedral B. 3 1 tetrahedral C. 2 2 bent D. 3 1 trigonal pyramidal E. 3 0 trigonal planar 2− 1. 2. 3. 4. − 6. Molecular Shape − 1 only 1, 2 and 3 1 and 3 1, 3 and 4 3 and 4 TeI4 SeBr4 XeCl4 NH3 AlF4 − The bond angles in H2O2 are approximately: A. B. C. D. E. 32 CO3 SOCl2 + H 3O 2 SO3 Which of the following molecules and ions possesses a tetrahedral molecular structure? A. B. C. D. E. 7. > BF3 SMALLEST Which of the following molecules has a trigonal planar structure? Which of the following is non–planar? A. B. C. D. E. BF3 Electron pairs orient themselves to give the smallest angles possible. Only bonding electron pairs are important in the VSEPR model. describes the spatial geometry of the atoms in the molecule. A. B. C. D. E. Among the following gaseous molecules 90° 105° 109.5° 120° 180° Chapter 9 continued 8. 11. Which of the following benzene–like molecules do you expect to have the largest dipole moment? Identify which of the following bonds is(are) polar and which element in each is the more electronegative. HCl NO F Cl Si2 A. Now consider these five statements about your conclusions. 1. 2. 3. 4. 5. F Cl F HCl is polar, with H the more electronegative. HCl is polar, with the Cl the more electronegative. NO is polar, with the N the more electronegative. NO is polar, with O the more electronegative. Si2 is polar. F H H F F B. H Cl The correct statement(s) above is(are) A. B. C. D. E. F H H C. 2 only 2 and 3 only 2 and 4 only 2, 3 and 5 only 1 and 4 only H H Cl H H 9. D. Consider the following molecules. 1. BF3 2. NH3 3. SOCl2 H 4. SiF4 F H H Which of these should have a dipole moment? A. B. C. D. E. F H F E. 2 only 2, 3 and 4 only 1, 2 and 3 ony 1 and 4 only 2 and 3 only H H F 12. Which of the following statements is true? 10. Which of the following molecules has the largest dipole moment? A. B. C. D. E. A. There are two π bonds in H H XeF2 XeF4 PF5 SF4 SF6 C C H H B. The H–N–H angle in NH3 is slightly larger than the H–C–H angle in CH4. 2 C. In CO2, the carbon is sp hybridized. D. The molecule below possesses a dipole moment. Cl H C C H Cl E. None of the above statements is true. 33 Chapter 9 continued 16. The following molecule should be used 13. Which of the following is a correct set of electron–pair geometry, hybridization, and bond angle(s)? Geometry Hybridization A. linear sp 2 B. trigonal planar sp 2 C. octahedral d sp D. tetrahedral dsp E. trigonal bipyramidal d sp 2 2 3 3 H C1 C2 Bond Angle(s) 180° 120° H H The hybridizations of C1, C2 and C3 respectively are 60° A. B. C. D. E. 120°, 90° 14. Of the following statements about delocalized bonds, which are true? 1. 2. 3. 4. 5. A. B. C. D. E. C C3 109.5° 3 H They occur in molecules with alternating single and double bonds. 2 They can be made from sp hybrid σ bonds. They are most often found in bonds involving heavy atoms. They can be made from π bonds. They rarely, if ever, involve bonds with fluorine. C1 3 sp 3 sp 3 sp 3 dsp C2 3 sp sp 3 sp sp C3 2 sp 2 sp 3 sp 2 sp None of the above. 17. Borazine B3N3H6 has been called inorganic benzene. What is the hybridization of the boron atoms? H H H N B B N H 1, 4, and 5 only 4 and 5 only 1, 3, and 4 only 1, 2, and 3 only All of the above A. B. C. D. E. 15. Which of the following statements is incorrect? A. Hybridization accounts for the experimental observation that all F−C−F bond angles in CF4 are the same. B. All C−C bond distances in benzene, C6H6, are the same. C. The energy required to break a carbon–carbon triple bond is greater than that needed to break a carbon–carbon double bond. D. The bonding in benzene, C6H6, includes 12 sigma (σ) bonds and 3 localized pi (π) bonds. E. The π electrons in NO3 are delocalized. − 34 sp 2 sp 3 sp 4 sp 3 dsp N B H H Chapter 10 1. 4. The volume of a large, irregularly shaped, closed tank is determined as follows. The tank is first evacuated, and then it is connected to a 50.0 L cylinder of compressed nitrogen gas. The gas pressure in the cylinder, originally at 21.5 atm, falls to 1.55 atm without a change in temperature. What is the volume of the tank? mass of A reacted: 5.00g mass of B reacted: 20.00g mass of C produced: 15.00g moles of D produced: 0.208 moles A. 100 L B. 644 L C. 25 L D. 744 L E. There is not sufficient information to determine the volume of the tank. 2. Solid substances A and B react to form a solid product C and a gaseous product D. Solids A, B, and C are weighed, and the volume, temperature and pressure of gas D are measured. From this and the ideal gas law, the number of moles of D are calculated. The data are: The molecular weight of D is A. B. C. D. E. Which curve represents the relationship between the volume of an ideal gas and its temperature in K at constant pressure? 5. A gaseous compound having the empirical formula CH2 has a density of 1.88 g/L at STP. The molecular formula for this compound is (assuming ideal behavior) A. B. C. D. E. 6. (E) None of the above. 3. A. Equal numbers of moles of two ideal gases of different molecular weight will fill the same volume at the same temperature and pressure. B. If the temperature of a given amount of an ideal gas is held constant, its pressure is directly proportional to the volume it occupies. C. The density of an ideal gas is independent of the volume it occupies at a given temperature and pressure. D. The mass of an ideal gas is proportional to its pressure at a fixed volume and temperature. E. The pressure of an ideal gas is proportional to its absolute temperature if its density is held constant. 35 CH2 C 2H 4 C 3H 6 C 4H 8 Not determinable from the data given. A gas which has a density of 2.77 g/L at STP is found to contain the following weight percents: 51.6% oxygen, 9.7% hydrogen, and 38.7% carbon. [Atomic weights are: C = 12.00 amu; H = 1.00 amu; O = 16.00 amu] The molecular formula for this gas is A. B. C. D. E. Which statement about ideal gases is incorrect? 48.1 2.08 72.1 208 Impossible to determine from the data given. CH3O C3H10O C 3H 9O 3 C 2H 6O 2 C 2H 4O Chapter 10 continued 7. 10. 3.0 L of He gas at 5.6 atm pressure and 25°C and 4.5 L of Ne gas at 3.6 atm and 25°C are combined at constant temperature into a 9.0 L flask. What is the total pressure (in atm) in the 9.0 L flask? Consider the following gases: H2S, H2, and SO2. Which of the following statements is accurate at any given temperature? A. B. C. D. E. A. The average kinetic energy of H2S is the same as that for H2. B. The rms speed of SO2 will be the same as that of H2S. C. The rms speed of SO2 will be greater than that of H2S. D. The average kinetic energy of SO2 will be greater than that of either H2S or H2. E. All molecules of H2S will have the same kinetic energy. 8. 11. A student collects the following data in the process of collecting nitrogen gas by water displacement: Volume of gas collected: 73.2 mL Temperature of room air and of water: 22.5°C Barometric pressure: 752 mm Hg Vapor pressure of water at 22.5°C (interpolated): 20.45 mm Hg An ideal gas at 200.0 K and 1.50 atm pressure is heated to 1000.0 K and kept at 1.50 atm pressure. Which of the statements 1–4 below are true? 1. 2. Assuming ideal gas behavior, which of the following is the number of moles of N2 the student collected? The root mean square speed of the molecules increases by a factor of five. The average molecular kinetic energy A. B. C. D. E. increases by a factor of twenty–five. 3. 4. A. B. C. D. E. 9. 2.6 9.2 1.0 3.7 4.6 The collision frequency with a unit area of container wall increases. The average molecular kinetic energy increases by a factor of five. 0.00290 moles N2 0.00299 moles N2 2.21 moles N2 2.27 moles N2 None of these is within 1% of the correct answer. 12. Which of the following statements is false? A. Dalton’s law of partial pressures indicates that in gaseous mixtures at low pressure each kind of molecule behaves independently of the others. B. At high pressures different gases give different values for the ratio PV/nRT. C. The mean free path of a molecule depends on its size. D. Collisions of molecules with the container walls give rise to the gas pressure. E. At a given temperature, for a given gas, every molecule has the same speed. 1 and 2 2 and 3 3 and 4 3 only 4 only Ideal gases A and B are kept in a 5.0–liter container at 20°C. The pressure of the gas mixture is 2.0 atm and it is known that 0.10 mole of gas A is present in the mixture. How many moles of B are present in the mixture? (MW of A = 25 amu; MW of B = 100 amu) 13. If the temperature of an ideal gas is held constant while its volume doubles, which one of the following happens? A. Insufficient information given to calculate moles of B present. B. 0.32 moles C. 0.25 moles D. 0.42 moles E. 0.48 moles A. The average velocity of the molecule increases. B. The frequency of collisions of gas molecules with a given area of wall decreases. C. The mean free path of the molecules remains unchanged. D. The density of the gas remains unchanged. E. None of the above is a true statement. 36 Chapter 10 continued 2. 14. The properties of a real gas are most likely to deviate from those properties predicted for an ideal gas when A. B. C. D. E. A. The large London dispersion forces between helium atoms make helium difficult to liquefy. B. Intermolecular forces in a liquid are weaker than intramolecular forces. C. Ion⎯ion forces in an ionic solution are independent of the distances between ions. D. Dipole⎯dipole forces dominate in interactions between carbon dioxide molecules. E. Van der Waals forces account for the cohesive energy of an ionic liquid. the pressure is low. the temperature is high. the pressure is high and the temperature is low. the pressure is low and the temperature is high. the density of the gas is low. 15. The fact that the ideal gas law only approximately describes the behavior of a gas might be partly explained by one or more of the following: 1. 2. 3. 4. Which of the following statements about intermolecular forces is true? 3. R is not really a constant. Gas molecules really do not have zero volume. The kinetic energy of gas molecules is not really directly proportional to the absolute temperature. Gas molecules really do interact with each other. Elementary phosphorus is a solid consisting of P4 molecules and melts at 44°C. The principal forces between the molecules in the solid must be A. B. C. D. E. London dispersion. ionic. covalent. dipolar. metallic. Which are correct? A. B. C. D. E. 4. 2 only 3 only 4 only 1 and 2 2 and 4 The boiling points of the substances MgO, Ne, and H2O should increase in the order A. B. C. D. E. H2O < MgO < Ne Ne < MgO < H2O MgO < Ne < H2O MgO < H2O < Ne Ne < H2O < MgO Chapter 11 1. 5. The boiling point of ammonia, NH3, is significantly higher than that of analogous compounds from the same group, e.g., PH3, AsH3, and SbH3. The principal reason for the abnormally high boiling point is A. B. C. D. E. The viscosity of a liquid is an important factor in A. B. C. D. E. London dispersion forces ion⎯dipole forces dipole⎯dipole interactions hydrogen bonding ion⎯induced dipole forces 6. Which of the following properties is not increased when the strength of intermolecular forces in a liquid is increased? A. B. C. D. E. 37 its rate of evaporation. capillary rise. bubble formation. rate of flow through a tube. its vapor pressure. vapor pressure heat of vaporization viscosity surface tension normal boiling point Chapter 11 continued 7. 10. Consider the three compounds sketched below: H H H H H C C C C O H H H H H O C C C O H H H H F C C C H H H H H H H H H H 1 2 3 F The viscosities of these three compounds should increase in the order A. B. C. D. E. 8. 1<2<3 2<3<1 3<2<1 3<1<2 1<3<2 The vapor pressure curves for two substances are shown in the figure. Identify which of X or Y has the higher normal boiling point and the larger intermolecular forces. A pure substance has a triple point in its phase diagram at 216 K and 5.1 atm. This means that: Higher Boiling Point A. at a pressure of one atmosphere the substance can coexist as a solid and vapor. B. at room temperature and one atmosphere pressure the substance is a liquid. C. above the triple point pressure and temperature the substance can exist only as a vapor. D. at a constant temperature of 216 K the substance is a solid at any pressure. E. at a constant pressure of 5.1 atm the substance is a liquid at any temperature. 9. A. B. C. D. E. Solid CO2 sinks in liquid CO2, and the triple point of CO2 is at –56.4°C and 5.11 atm pressure. What state of CO2 exists at –56.4°C and 6.00 atm pressure? A. B. C. D. E. Gas Liquid Solid Supercritical fluid Mixture of solid and liquid . 38 Larger Intermolecular Forces Y Y X X Y X X Y Insufficient data given to determine the answer. Chapter 11 continued 12. 11. Which of the following compounds has the lowest vapor pressure at 0 °C? A. Which of the following would you expect to have the highest boiling point? CH3 CH CH2 CH3 CH3 A H B. C CH3 CH H CH3 B OH C. C HO OH CH3 D. D CH3 H3C C CH3 H H H H H H H C C C C C C H H H H C H H H H H H H H H H H C C C H H C C C H H H H H H CH3 H H H H H H OH E HOH C 2 E. C CH2OH H C C C C C C H H H H H H H C H H C H H H 39 Chapter 11 continued Chapter 13 13. Rank these in order of decreasing boiling point 1. The mole fraction of CO2 in a certain solution with 4 H2O as the solvent is 3.6 × 10 . The molality of CO2 in this solution is about − A. B. C. D. E. H H H i) H—C—C—C—H H H H 2. H Cl ii) iii) H Cl H H A. B. C. D. E. A solution contains 4.00 g NaOH, 5.61 g KOH, and 1.03 g RbOH in 90.0 g of water. The solution has a density of 1.08 g/mL. What is the molality of OH ? A. B. C. D. E. H—C—C—C—Br H − − H—C—C—Br H 0.00036 m 0.0065 m 0.020 m 5 2.0 × 10 m 6.5 m 3. 2.33 m 2.09 m 2.52 m 2.16 m None of the above is within 2% of the correct answer. The mole fraction of HCl in a 36% by weight aqueous solution of HCl is H H A. B. C. D. E. iii > ii > i i > ii > iii ii> i > iii iii > i > ii i > iii > ii 4. A solution whose density is 0.935 g/mL contains 30.0% by weight H2CO, 10.0% C2H5OH and 60.0% H2O. The molarity of the H2CO is A. B. C. D. E. 5. 9.34 M 2.32 M 0.0107 M 4.51 M 0.0214 M 27.0 L of HCl gas at STP is dissolved in water, giving 785 mL of solution. The molarity of the HCl solution is: A. B. C. D. E. 40 0.11 0.22 0.36 0.64 0.99 9.46 M 1.53 M 0.946 M 15.3 M None of the above is within 1% of the correct answer. Chapter 13 continued 6. 10. Which one of the following statements is true? A. B. C. D. A. The heat of solution in H2O for KOH is the same as that for KOH H2O. B. For a compound to spontaneously dissolve in H2O at 25°C, the solution process must be exothermic. C. Ne is less soluble in H2O at 2 atm pressure than at 1 atm pressure. D. C2H4 is very soluble in liquid NH3. E. None of the above. Given the solutes NaCl and I2 and the solvents NH3(l) and C7H16 (heptane), which is true? CH2OH Which one of the following would you expect to be LEAST soluble in water A. B. C. D. A. NaCl and I2 are both more soluble in NH3 than in C7H16. B. NaCl and I2 are both more soluble in C7H16 than in NH3. C. NaCl is more soluble in NH3; I2 is more soluble in C7H16. D. NaCl is more soluble in C7H16; I2 is more soluble in C7H16. E. In order to determine relative solubilities in these cases one must know whether the solution reactions are exothermic or endothermic. 8. CH3OH CH3CH2CH2OH CH3CH2 CH2 CH2CH2OH CH3CH2 CH2 CH2CH2CH3 E. 11. 7. Which one of the following would you expect to me MOST soluble in water? CH3OH CH3CH2CH2OH CH3CH2 CH2 CH2CH2OH CH3CH2 CH2 CH2CH2CH3 E. CH2OH 12. Rank these in order of decreasing solubility in water. i) The Henry’s law constant for He gas in H2O at 30°C 4 is 3.7 × 10 M/atm; that for N2 at 30°C is 4 6.0 × 10 M/atm. If a gaseous He-N2 mixture that has a He mole fraction of 0.30 is placed over the water CH3 − − ii) HO A. the concentration of dissolved He will be greater than that of dissolved N2. B. the concentration ratio of dissolved He to dissolved N2 would be 0.62. C. the concentration ratio of dissolved He to dissolved N2 will be 0.26. D. the concentration ratio of dissolved He to dissolved N2 will be 0.18. E. the concentration ratio of dissolved He to dissolved N2 will be 0.49. 9. CH3 iii) CH3CH2OH A. B. C. D. E. A saturated solution of silver chloride, AgCl is weakly conducting for electricity because i > ii> iii iii > i = ii ii > iii > i iii > ii > i i = ii > iii 13. Arrange the following aqueous solutions in order of increasing boiling points: A. AgCl is essentially 100% ionized in solution, but is not very soluble. B. AgCl is quite soluble, but only dissociates into ions slightly, in solution. C. AgCl does not produce ions itself, but rather induces hydrolysis to give AgOH and HCl, in water. D. AgCl is only slightly ionized in solution, and also is only slightly soluble. E. None of the above is a true statement. 1. 2. 3. 4. 5. A. B. C. D. E. 41 0.1 M Fe2(SO4)3 0.2 M BaCl2 0.3 M glucose (blood sugar) 0.2 M LiCl 0.2 M AlCl3 3, 4, 2, 1, 5 2, 4, 5, 1, 3 5, 3, 1, 4, 2 3, 4, 1, 2, 5 3, 5, 2, 1, 4 Chapter 13 continued 18. Arrange the following aqueous solutions in order of increasing vapor pressure: 14. Consider a solvent whose molecular weight is 100.0 amu and whose vapor pressure at 25°C is 25.00 mm Hg. 100.0 g of a nonvolatile solute whose molecular weight is 50.00 amu is dissolved in 1.000 kg of that solvent. The solute is not an electrolyte. What is the vapor pressure of the solution at 25°C? A. B. C. D. E. 1. 2. 3. 4. 5. A. B. C. D. E. 0.01 mm Hg 20.8 mm Hg 22.7 mm Hg 24.9 mm Hg 25.0 mm Hg 15. The compound ethylene glycol, C2H6O2, is widely used as an automotive antifreeze. What is the minimum weight, in grams, of this compound that must be added to 8 kg of water to produce a solution that will protect an automobile cooling system from freezing at −20°F (−28.9°C)? Ethylene glycol is a non–electrolyte. A. B. C. D. E. 1, 2, 3, 4, 5 5, 4, 3, 2, 1 2, 1, 4, 3, 5 4, 2, 3, 1, 5 5, 3, 4, 1, 2 Chapter 15 1. 32.0 121 7720 965 5342 Kc for the reaction HCl(g) + NH3(g) → NH4Cl(s) is A. [NH 4 Cl] [HCl][NH 3 ] B. [HCl][NH 3 ] [NH 4 Cl] C. 1 [HCl][NH 3 ] D. [HCl] [NH3] 16. 7.50 g of a compound having the empirical formula CH2O is dissolved in water to form 100.0 mL of solution. This solution does not conduct electric current and is found to have an osmotic pressure of 12.2 atm. at 25°C. The molecular formula for the compound is A. B. C. D. E. 0.5 M NaCl 0.4 M Na2SO4 0.1 M KCl 0.1 M Al2(SO4)3 0.1 M C6H12O6 (sugar) E. [NH4Cl] 2. CH2O C 3H 6O 6 C5H10O5 C6H12O6 None of the above is the correct answer Consider the following three reactions: 1. H2(g) + Cl2(g) ⇄ 2 HCl(g) 2. C(s) + H2O(g) ⇄ CO(g) + H2(g) 3. Fe3O4(s) + 4H2(g) ⇄ 3 Fe(s) + 4H2O(g) For which of these would Kp = Kc? A. B. C. D. E. 17. The addition of nonvolatile solute to a solvent A. increases the boiling point, decreases the freezing point and increases the vapor pressure of the solvent. B. decreases the boiling point, decreases the freezing point and decreases the vapor pressure of the solvent. C. decreases the boiling point, increases the freezing point and increases the vapor pressure of the solvent. D. increases the boiling point, decreases the freezing point and decreases the vapor pressure of the solvent. E. increases the boiling point, decreases the freezing point but leaves the vapor pressure of the solvent unaffected. 3. 1 only 1 and 2 only 1 and 3 only 3 only 2 and 3 only 3 At 50°C, Kc = 2.2 × 10 for the reaction 3 Fe(s) + 4 H2O(g) ⇄ Fe3O4(s) + 4 H2(g) What is the value of Kp at 200°C for this reaction? A. B. C. D. E. 42 3 8.8 × 10 3 2.2 × 10 2 5.5 × 10 4 3.5 × 10 This question cannot be answered with the information provided Chapter 15 continued 4. 7. For the following reaction, Kp = 1.96 at 700 K. NOCl(g) ⇄ NO(g) + ½ Cl2(g) At this same temperature, Kp for the reaction Cl2(g) + 2 NO(g) ⇄ 2 NOCl (g) A. B. C. D. E. is A. B. C. D. E. 5. 6. 1.96 3.85 0.260 0.509 None of the above is within 5% of the correct answer. 8. Kc for the reaction F2(g) + Cl2(g) ⇄ 2 FCl(g) equals 125 at a particular temperature. Suppose a system involving this reaction is already at equilibrium and the concentrations of F2 and Cl2 are found to be [F2] = 0.115 M and [Cl2] = 0.221 M. What is the concentration of FCl in the system? A. B. C. D. E. 2 [NO] = 0.25 M [NO] = 0.50 M [NO] = 1.0 M [NO] = 0.67 M None of the above is within 5% of the correct answer − 9. At 750°C, Kp = 0.770 for the reaction H2(g) + CO2(g) ⇄ H2O(g) + CO(g) At a certain temperature, 0.300 moles of NO, 0.200 moles of Cl2, and 0.500 moles of ClNO were placed in a 25.0 L vessel and allowed to reach equilibrium: If 0.200 atm of H2 and 0.200 atm of CO2 are admitted into a rigid container and allowed to reach equilibrium, what should the equilibrium partial pressure of CO be? 2 NO(g) + Cl2(g) ⇄ 2 ClNO(g). At equilibrium, 0.600 moles of ClNO were present. The number of moles of Cl2 present at equilibrium is A. B. C. D. E. 6 – (X/2) 6–X 6 – 2X 3 – 2X None of the above is correct For the reaction N2(g) + O2(g) ⇄ 2 NO(g) Kc = 4.0 at a particular temperature. Suppose we begin an experiment by mixing 1.0 mol of N2 and 1.0 mol of O2 in a 1.0–liter container. What will be the concentration of NO once equilibrium is reached at the given temperature? A. B. C. D. E. [FCl] = 2.54 × 10 M [FCl] = 3.17 M [FCl] = 1.78 M 2 [FCl] = 1.43 × 10 M None of the above is within 5% of the correct answer − Consider the reaction 2 NH3(g) ⇄ N2(g) + 3 H2(g). Suppose 6 moles of pure NH3 are placed in a 1.0–liter flask and allowed to reach equilibrium. If X represents the concentration in moles per liter of N2 present in the system once equilibrium is reached, which one of the following will represent the concentration of NH3 at equilibrium in moles per liter? A. B. C. D. E. 0.100 0.150 0.200 0.250 0.300 43 0.0935 atm 0.109 atm 1.43 atm 0.100 atm 0.770 atm 13. For the reaction FeO(s) + CO(g) ⇄ Fe(s) + CO2(g), Chapter 15 continued 10. At high temperatures one mole of hydrogen gas reacts with one mole of bromine gas to form hydrogen bromide. At a given temperature the equilibrium constant is 57.6. If at the same temperature, a 3 3 mixture of 4.67 × 10 M bromine gas, 2.14 × 10 2 hydrogen gas, and 2.40 × 10 M hydrogen bromide gas is made, then − A. the usual expression for the equilibrium constant is Kc = [Fe] [CO2 ] [FeO] [CO] B. addition of CO2(g) will increase Kc. C. increasing the volume of an equilibrium mixture at constant temperature will cause the number of − − moles of CO2 to increase as the mixture re– A. the system is at equilibrium. B. the system is far from equilibrium and will shift to form more hydrogen gas. C. the system is far from equilibrium and will shift to form more hydrogen bromide gas. D. nothing can be deduced since we do not know whether the reaction is endothermic or exothermic. E. nothing can be deduced since we do not know whether the equilibrium constant is Kc or Kp. equilibrates. D. adding more FeO to an equilibrium mixture will cause the number of moles of CO2 to increase as the system re–equilibrates. E. None of the above statements is true Chapter 18 11. Which one of the following equilibriums is least affected by a change in the volume of the system? 1. A. 2 C(s) + O2(g) ⇄ 2 CO(g) B. 2 NO2(g) ⇄ N2O4(g) A. B. C. D. E. C. H2(g) + S(ℓ) ⇄ H2S(g) D. H2O(ℓ) ⇄ H2O(g) E. 2 NO(g) + Cl2(g) ⇄ 2 NOCl(g) 12. Nickel (II) oxide can be reduced to nickel metal by treatment with carbon monoxide as indicated in the reaction 2. If the reaction chamber contains some solid Ni and NiO, 400 mm Hg of CO2 and 20 mm Hg of CO, all at equilibrium, which one of the following changes will lead to the reduction of more nickel oxide at 500°C? 3. Doubling the amount of NiO(s) present. Adding CO2 to raise its pressure to 700 mm Hg. Adding CO to raise its pressure to 40 mm Hg. Removal of half of the NiO(s) present. Doubling the volume of the reaction chamber at 500°C. 275 nm 45.0 nm 742 nm 353 nm 137 nm Which species is primarily responsible for absorbing ultraviolet radiation in the stratosphere? A. B. C. D. E. 44 CFCl3 CO2 O2 N2 NO2 The C−Cl bond dissociation energy in CF3Cl is 339 kJ/mol. What is the maximum wavelength of photons that can rupture this bond? A. B. C. D. E. CO(g) + NiO(s) ⇄ CO2(g) + Ni(s) Kp=20 at 500°C A. B. C. D. E. Select the substance that is thought to be partially responsible for depleting the concentration of ozone in the upper atmosphere. N2 O3 CO CH2Cl2 CO2 REACTIONS 1. 5. When the following equation A. the compound contains C, H, and some other element of unknown identity, so we can’t calculate the empirical formula. B. the compound contains only C and H and has the empirical formula of C6H. C. the compound contains C, H, and O and has the empirical formula of CH3O. D. the compound contains only C and H and has the empirical formula of CH2. E. None of the above is a true statement C9H15S + O2 → CO2 + H2O + SO2 is balanced with the smallest possible set of integer coefficients (no fractions), the coefficient preceding CO2 is A. B. C. D. E. 9 27 36 18 None of the above is correct 6. 2. When the equation for the complete combustion of ethanol, C2H5OH, to form CO2 and H2O is balanced with lowest–integer coefficients, the coefficient for O2 is A. B. C. D. E. 3. Mixing solutions of K2SO4(aq) and BaCl2(aq) produces an insoluble salt. Which of the following is the correct list of spectator ions for this reaction? A. B. C. D. E. 7 6 5 3 None of the above answers is correct 7. A 100.0 g sample of a metal M is burned in air to produce 103.7 g of its oxide with the formula M2O. What is the atomic mass of the metal? A. B. C. D. E. 1.00 g of a compound is combusted in oxygen and found to give 3.14 g of CO2 and 1.29 g of H2O. From these data we can tell that + 2– K , SO4 , Ba + 2– K , SO4 + – K , Cl 2+ – Ba , Cl 2+ 2– Ba , SO4 2+ +3 2− 2+ A. 2Fe (aq)+ 3SO4 (aq) + 3Pb (aq)+ 6NO3 (aq) → 73 amu 150 amu 216 amu 290 amu 370 amu 2+ − 2− 2Fe(NO3)3(s) + 3Pb (aq) + 3SO4 (aq) +3 2− 2+ B. Fe (aq)+ SO4 (aq) + Pb (aq) + 3NO3 (aq) → − Fe(NO3)3(s) + PbSO4(s) C. Fe (aq) + 3NO3 (aq) → Fe(NO3)3(s) 4.31 g of a hydrocarbon is completely combusted in oxygen and found to yield 6.36 g of water. The empirical formula for the hydrocarbon is A. B. C. D. E. – When aqueous solutions of Fe2(SO4)3 (aq) and Pb(NO3)2(aq) are mixed, an insoluble salt forms. Which of the following reactions is the correct net ionic equation that describes this reaction? +3 4. , Cl − 2+ D. Pb (aq)+ 2NO3 (aq) → Pb(NO3)2(s) 2+ − 2− E. Pb (aq)+ SO4 (aq)→ PbSO4(s) C 3H 7 CH4 C 7H 4 C21H4 CH 8. Which of these reactions will form a precipitate in water? A. Mg(OH )2 + 2 HCl → Mg(Cl)2 + 2H2O B. Mg(OH)2 + (NH4)2SO4 → MgSO4 + 2 NH3 + 2 H2O C. CaCO3 + 2 HCl → CaCl2 + CO2 + H2O D. HCl + CH3COOK → CH3COOH + KCl E. Ba(NO3)2 + K2SO4 → BaSO4 + 2 KNO3 45 REACTIONS continued 12. The oxidation number of Mo (molybdenum) in 6 Mo7O24 is: − 9. Which one of the following (unbalanced) equations describes a spontaneous reaction? A. B. C. D. E. A. Ag(s) + HCl(aq) → AgCl(s) + H2(g) 3+ 2+ B. Hg(l) + Al (aq) → Hg (aq) + Al(s) 2+ +6 +5 +4 +3 +2 2+ C. Cu (aq) + Zn(s) → Cu(s) + Zn (aq) D. Ni(s) + H2O(l) → Ni(OH)2(s) + H2(g) 13. 100.0 mL of Ca(OH)2 solution is titrated with 2 5.00 × 10 M HBr. It requires 36.5 mL of the acid solution for neutralization. The concentration of the Ca(OH)2 solution is E. None of the above describes a spontaneous reaction. 10. − A. B. C. D. E. Given that the three standard reactions shown below proceed as written, which of the subsequent 3 reactions do not occur. Standard reactions Mg(s) + ZnCl2(aq) → Zn(s) + MgCl2(aq) 3 9.12 × 10 M 4 1.82 × 10 M 4 9.12 × 10 M 3 1.82 × 10 M None of the above is within 1% of the correct answer − − − − Zn(s) + FeCl2(aq) → Fe(s) + ZnCl2(aq) 14. Given the balanced equation for the oxidation of ethanol, C2H5OH, by potassium dichromate: Fe(s) + CuCl2(aq) → Cu(s) + FeCl2(aq) I. Mg(s) + FeCl2(aq) → Fe(s) + MgCl2(aq) 3C2H5OH + 2K2Cr2O7 + 16HCl → II. Zn(s) + CuCl2(aq) → Cu(s) + ZnCl2(aq) 3C2H4O2 + 4CrCl3 + 4KCl + 11H2O III. Fe(s) + ZnCl2(aq) → Zn(s) + FeCl2(aq) A. I only B. II only C. III only D. I and II E. I and III Calculate the volume of a 0.600 M K2Cr2O7 solution needed to generate 0.1665 moles of C2H4O2 from a solution containing excess ethanol and HCl. A. B. C. D. E. 11. Which of the following reactions are redox reactions? 15. How many grams of solid NaOH will be needed to neutralize 85.0 mL of a 0.275 M solution of H2SO4? 1. Ni(OH)2(s) + H2SO4(aq) → NiSO4(aq) + 2 H2O() A. B. C. D. E. 2. 8 NH3(g) + 6 NO2(g) → 7 N2(g) + 12 H2O() 3. 3 PbO(s) + 2 NH3(aq) → N2(g) + 3 H2O() + 3 Pb(s) A. B. C. D. E. 278 mL 185 mL 111 mL 6.60 mL None of the above answers is correct 1 only 2 only 3 only 1 and 3 2 and 3 0.94 g 19.1 g 1.87 g 0.47 g 6.41 g 16. When 47.3 mL of 0.107 M HCl is added to 54.7 mL of 0.213 M NaOH, the resulting OH concentration is: − A. B. C. D. E. 46 0.028 M 0.065 M 0.114 M 0.120 M 0.213 M REACTIONS continued 17. A method of removing CO2(g) from a spacecraft is to allow it to react with solid NaOH: 20. Which of the following compounds would react most rapidly with bromine (Br2) at room temperature? a) pentane 2 NaOH(s) + CO2(g) → Na2CO3(s) + H2O(ℓ) How many liters of CO2(g) at 26.0°C and 755 mm Hg can be removed per kg NaOH? b) toluene A. B. C. D. E. c) ethanol 24.7 16.3 12400 618 309 e) 2-hexene CH3 - CH2 - OH CH3 - CH2 - CH2 - CH = CH - CH3 21. Choose the appropriate words to fill in the blanks. A condensation reaction between a _______ and a _______ will form an _________. 10.0 L 20.0 L 30.0 L 40.0 L None of the above is correct. A. amide, ester, alcohol B. amine, carboxylic acid, amide C. alcohol, amine, amide D. alcohol, alcohol, ester E. alcohol, carboxylic acid, amide 19. The following reactions involve only gases. Which of them, if carried out in a closed container at constant temperature, would proceed with a decrease in pressure? A. B. C. D. E. CH3 d) cyclopentane 18. A gaseous sample of pure methane, CH4, is found to occupy a volume of 20.0 L at 25°C and 1 atm pressure. What volume of O2, at the same temperature and pressure, should be just sufficient to permit complete combustion of the methane? A. B. C. D. E. CH3 - CH2 - CH2 - CH2 - CH3 2 CO + O2 → 2 CO2 2 NH3 → N2 + 3 H2 N2 + O2 → 2 NO 2 O3 → 3 O2 2 HI → H2 + I2 47 Chem 110 Supplemental Problems Answer Key Chapter 1 1. A 2. E 3. B 4. C 5. A Chapter 2 1. C 2. A 3. D 4. D 5. D Chapter 3 1. C 2. B 3. A 4. E 5. D 6. B 7. B 8. D 9. E Chapter 4 1. B 2. E 3. E 4. C 5. C Chapter 5 1. E 2. D 3. E 4. A 5. A 6. D 7. D Chapter 6 1. D 2. D 3. B 4. E 5. A 6. C 7. E 8. C 9. E 10. D 11. B 12. C 13. C 14. B 15. A 16. B Chapter 7 1. B 2. B 3. D 4. A 5. D 6. D 7. B 8. E 9. E 10. E 11. D 12. D Chapter 8 1. A 2. B 3. D 4. B 5. E 6. B 7. B 8. B 9. A 10. B 11. A 12. A 13. B 14. C Organic 1. D 2. D 3. D 4. A 5. C 6. B 7. B 8. E 9. D Chapter 9 1. E 2. C 3. D 4. A 5. A 6. E 7. B 8. C 9. E 10. D 11. D 12. E 13. B 14. A 15. D 16. E 17. B Chapter 10 1. B 2. B 3. B 4. A 5. C 6. D 7. A 8. E 9. B 10. D 11. A 12. E 13. B 14. C 15. E 48 Chapter 11 1. D 2. B 3. A 4. E 5. D 6. A 7. D 8. A 9. C 10. A 11. E 12. E 13. A Chapter 13 1. C 2. A 3. B 4. A 5. B 6. E 7. C 8. C 9. A 10. A 11. D 12. D 13. D 14. B 15. C 16. C 17. D 18. C Chapter 15 1. C 2. C 3. E 4. C 5. C 6. B 7. C 8. C 9. A 10. A 11. C 12. C 13. E Chapter 18 1. A 2. D 3. B Chemical Reactions 1. C 2. D 3. C 4. A 5. D 6. C 7. E 8. E 9. C 10. C 11. E 12. A 13. A 14. B 15. C 16. B 17. E 18. D 19. A 20. E 21. B 49