Chemistry 006 Practice Final. 6. What is the predominant intermolecular force in carbon tetrachloride, CCl4?

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Valentine Gilbert
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1 hemistry 00 Practice Final 1. The boiling point of l(l) is higher than the boiling point of Ar(l) as a result of hydrogen bonding higher formula mass stronger London forces permanent dipole forces ion-ion forces. Which of the following truly describes the atmosphere? Temperature increases in regular way with increasing altitude. Pressure increases in a regular way with increasing altitude. oncentrations of all major air pollutants increase in a regular way with increasing altitude. Temperature decreases in a regular way with increasing altitude Pressure decreases in a regular way with increasing altitude. 3. Which of the following molecules will have the largest dipole moment? S SF XeF BF3 F 4. Which of the following substances has the strongest intermolecular attractions? e, boiling point!8. Ne, boiling point!45.9 Ar, boiling point!185.7 Kr, boiling point!15.3 All have equally strong intermolecular attractions. 5. The molecular shape of AsF5 is expected to be trigonal bipyramidal T-shaped octahedral tetrahedral square planar 1. What is the predominant intermolecular force in carbon tetrachloride, l4? London dispersion force ion-dipole attraction ionic bonding dipole-dipole attraction hydrogen-bonding 7. Given the following samples of gases N N N 1.0 atm 0.5 atm 1.0 atm 0.5 atm I II III IV Which of the following statements are false? 1. I and II have the same average kinetic energy.. II and IV have the same average kinetic energy. 3. I has a higher average speed than III. 4. I has a higher average speed than II. 1 and are false 1 and 3 are false 1 and 4 are false and 3 are false and 4 are false 8. Place the following in order of increasing first ionization energy F,, Ne, s, Rb, Fe. F < < Ne < s < Rb < Fe Fe < Ne < < F < s < Rb s < Rb < Fe < < F < Ne Ne < Fe < s < Rb < < F s < Rb < < Fe < F < Ne

2 9. Which one of the following species has as many electrons as it has neutrons? 1 40 a F! 35 S! 10. A real gas, such as, is expected to show ideal behavior when a liquid is present. at low temperature. at high pressure and low temperature. at low pressure and high temperature. at high pressure. 11. The balanced homogeneous vapor-phase reaction G + Q + Z has Kc = 5.3 x 10!4. At equilibrium products dominate. reactants dominate. approximately equal molar amounts of reactants and products are present. only products exist. only reactants exist. 1. The bond angles in N! 3 are expected to be 13. Ethanol and gasoline (assumed to be all octane, 818) are both used as automotive fuels. If gasoline is selling for $1.7/gallon what would the price of ethanol have to be to provide the same amount of heat per dollar based on the following data? octane ethanol enthalpy of combustion, kj/gram!47.89!9.9 density, g/ml one gallon = 3.785L (hint: you don t need this to solve the problem) $0.45 $0.4 $0.70 $0.88 $ onsider the following reaction and conditions: (g) + 3(g) 4(g) + (g) Kc = 3.89 [4] = M [] = M [] = M [] = 0.15 M At these conditions, which one of the following statements is true? The reaction must proceed to the right to attain equilibrium. The reaction must proceed to the left to attain equilibrium. The reaction is at equilibrium. The equilibrium status cannot be determined from the given information. Addition of a catalyst will shift the equilibrium to the left. 3 4

3 15. Use the table of bond dissociation energies to calculate " (in kj) for the following gas-phase reaction.! !38 Bond + l D (kj/mol) = l 431 -l The enthalpy of combustion of (graphite) to gas is!393.5 kj/mol of. The enthalpy of the conversion of (graphite) to (diamond) is kj/mol of. Which process gives off the most heat? combustion of graphite combustion of diamond a and b are the same based on the information given, diamond doesn t burn 17. Which of the following elements is most likely to form compounds in which its valence shell is expanded beyond an octet? l 18. The equilibrium constant expression for the following equilibrium is N K = [ ][ ] c [ N ][ ] N3(g) + (g) 3 N K = [ ][ ] 3 c [ N ] [ ] N Kc = [ ] [ ] 3 3 [ N ][ ] 3 N K = [ ][ ] c [ N ][ ] 3 N K = [ ][ ] 3 c [ N ][ ] 3 N(g) + 3(g) 19. Ascorbic acid (vitamin ) cures scurvy and may help prevent the common cold. It is composed of,, and, with 40.9% and 4.58%. The empirical formula of ascorbic acid is More information is needed to determine the empirical formula Li B Br 5

4 0. The Lewis formulas for five molecules are given below. Which molecule can hydrogen bond to other molecules of the same kind? Refer to the following diagram to answer the next two questions. N P T R E Z Y X S S U R W V E Temp. Temperature time. Referring to the phase diagram, the graph of temperature against time shows which change? X to Y W to V V to W X to Z Z to X 1. At 0, 5 moles of, moles of N and 1 mole of l are mixed in a 40 liter flask. Assuming ideal behavior, the total pressure of the mixture is 44.8 atm atm..80 atm. 1.1 atm. 0.5 atm. 3. Which phase(s) is(are) present at point T? gas liquid solid both liquid and gas both solid and liquid 4. The most common ion formed by calcium is: a + a! a! a + a

5 5. In which of the following solutions is molality most nearly equal to molarity? 0.30 M aqueous KI M aqueous KI 0.30 M KI in 3 (The density of 3 is g/cm 3.) M KI in 3 Molality is never nearly equal to molarity. 9. Which one of the following molecules DES NT have -bonding as one of it s intermolecular forces? 1... What is the formal charge of sulfur in S 3!? N 3 7. The noble gases are monatomic, consisting of single atoms. The reason the noble gases don t really form compounds is: 3. 4 Their ionization energies are extremely high. They are too small to bond. They already have an octet configuration a and c a, b and c A 00 ml solution containing phosphate ions is treated with enough solid calcium nitrate to precipitate all the phosphate ions. What was the original phosphate concentration if 0.77g of calcium nitrate is exactly needed to complete the precipitation? 8.44 x 10! 3 M 5.3 x 10! 3 M 3.38 x 10! 3 M 1.9 x 10! 3 M 1.13 x 10! 3 M 5. 1, 3, 5 1, 4 none: all of them are able to form - bonds. 9 10

6 30. Starting with pure l, if the initial concentration of l is M and the equilibrium concentration of is 0.03 M, what is the value of Kc for the equilibrium 1.54 x 10! 4.5 x 10! x x 10 1 l(g) (g) + l(g) 31. Identify the correct equilibrium expression (Kc) for the following reaction. [ 1 ][ ] [ ][ ] (g) + (l) 1(s) + (g) 33. The energy associated with breaking the bond in # is 107 kj.mol. The wavelength of radiation required to break this bond is: greater than 11 nm less than 11 nm greater than 4 nm exactly 4 nm the bond cannot be broken 34. The following substances are fertilizers that contribute nitrogen to the soil: urea [(N)]; ammonium nitrate; ammonium sulfate. Arrange these fertilizers in order of decreasing nitrogen content on a mass percentage basis. ammonium nitrate > urea > ammonium sulfate ammonium nitrate > ammonium sulfate > urea urea $ ammonium sulfate $ ammonium nitrate urea > ammonium nitrate > ammonium sulfate ammonium sulfate $ ammonium nitrate > urea 35. onsider the following reaction at equlibrium N3(g) N(g) + 3(g) = +9.4 kj [ ] [ ] [ ] [ ] [ ] [ ] [ ] Adding N(g) to the reaction vessel will decrease the concentration of N3(g) at equilibrium decrease the concentration of (g) at equilibrium increase the value of the equilibrium constant cause the reaction to shift to the right have no effect on the concentration of N3(g) 3. Which of the following bonds would you expect to be strongest? 3. (g) + 3(g) 1(g). When 1.00 mol and 3.00 mol are put into a 00 L container and allowed to reach equilibrium over a catalyst at an elevated temperature, the resulting mixture contains mol 1. What is the equilibrium amount of in moles? N#N N=N N%N F%F % 11 1

7 37. The formula of a salt is Xl. The metal ion in the salt has 8 electrons. The metal must be Ni Fe V Pd Zn 38. A solution of MX prepared by dissolving 0.00 moles of MX in 115g of water freezes at!0.5. The material MX is (Kf = 1.8 /m for water) a non electrolyte a weak electrolyte a strong electrolyte not determinable from this information 39. The number of unpaired electrons in the lowest energy state of the boron atom (B) is: Three solutions, labeled A, B, and, each contain a different unknown solute. When a solution of silver nitrate is added to samples of A, B, and, a precipitate occurs with A and B but not with. When a solution of (N4) S4 is added to samples of A, B, and, a precipitate occurs only with. Among the following possibilities, which one is consistent with the experimental observations? A B NaN3 NaS Nal KI Nal NaN3 NaS Nal Ba(N3) N4N3 Bal Pb(N3) NaN3 N4N3 Pb(N3) 41. The molecule N! contains delocalized &-electrons. True False 4. A ' bond is a stronger bond than a & bond because of the greater effective overlap of atomic or hybrid orbitals and because there is more electron density directly between the bonded nuclei. True False 43. If the mole fraction of a gas in a mixture increases, the partial pressure of the gas will increase. True False 44. The volume of a gas doubles when the temperature in centigrade doubles if all other variables are held constant. True False 45. The formation of nitrogen atoms from the reaction of N + with electrons in the atmosphere is an example of photoionization. True False 4. In the Bohr model of the hydrogen atom, energy is emitted when an electron goes from the n= to the n=4 level. True False 47. If an electron is in a 4d orbital, it could have quantum numbers n=3, l=4, m l =0, and ms=!1/. True False 48. Alkenes are more reactive than aromatic hydrocarbons because they have delocalized & bonds. True False 49. The melting point of LiF is greater than the melting point of KF. True False 50. Phosphorus has more metallic character than aluminum. True False 51. There are 0.14 moles of l! in 35 ml of M ul True False 13 14

8 5. At the equivalence point in the neutralization reaction below, the moles of acid = the moles of base. Na + I ( NaI + True False 53. In the balanced equation for the complete combustion of propanol, 3 the coefficient for is. True False 54. The maximum possible number of electrons in the 3d subshell is 10. True False 55. In the following reaction, the heat of reaction is equal to "f of Agl(s) True False Ag + (aq) + l! (aq)! Agl(s) 5. There are 4 pairs of unshared electrons in. True False 57. For the series, Na +,!, F! :! has the smallest radius. True False 58. For a multi-electron atom, there are five 3d orbitals which are degenerate. True False 59. The ' bond joining the two carbons in ethane is the result of the overlap of a p-orbital and an sp 3 hybrid orbital. True False 0. At high pressure and high temperature, a gas is expected to behave ideally. True False 15

CHM 151 Practice Final Exam

CHM 151 Practice Final Exam CM 151 Practice Final Exam 1. ow many significant figures are there in the result of 5.52 divided by 3.745? (a) 1 (b) 2 (c) 3 (d) 4 (e) 5 2. ow many significant figures are there in the answer when 9.021