NOTE: This practice exam contains more than questions than the real final.

Transcription

1 NOTE: This practice exam contains more than questions than the real final. 1. The wavelength of light emitted from a green laser pointer is nm. What is the wavelength in meters? 2. What is the correct answer, with correct significant figures, to the following expression: ( ) ? 3. At 25 ºC, the density of oxygen in air is g/l. What volume is occupied by 25 kg of oxygen at 25 C? 4. How many protons, neutrons, and electrons are in an oxygen-18 atom? a) 6 protons, 8 neutrons, 4 electron b) 6 protons, 10 neutrons, 8 electrons c) 8 protons, 8 neutrons, 8 electrons d) 8 protons, 10 neutrons, 8 electrons e) 8 protons, 10 neutrons, 18 electrons 5. What is the identity of X? 6. Which two of the following atoms are isotopes? Sc, Ti, Ti, V 7. Bromine has two naturally occurring isotopes. The average mass of bromine is u. If 50.54% of bromine is found as bromine-79 ( u), what is the mass of the other isotope? 8. You have mole of each of the following elements: Be, B, Br, Ba, and Bi. Which sample has the largest mass? 9. A 3.6 g sample of lithium contains atoms. 10. How many elements are in the fifth period of the periodic table? 11. What is the correct formula for an ionic compound that contains magnesium ions and fluoride ions? 12. What is the correct name for NH 4 ClO 4? 13. What is the correct name for Cr(NO 3 ) 2? 14. What is the correct name for PF 5? 15. What is the mass percent of chlorine in iron(ii) chloride? 16. A molecule is found to contain 47.35% C, 10.60% H, and 42.05% O. What is the empirical formula for this molecule? 17. An organic solvent has the empirical formula CH. If the molar mass of this solvent is g/mol, what is the molecular formula of benzene? 18. Ammonia is prepared by reacting nitrogen and hydrogen gases at high temperature according to the unbalanced chemical equation below. N 2 (g) + H 2 (g) NH 3 (g) What are the respective coefficients when the equation is balanced with the smallest whole numbers? 19. What is the net ionic equation for the reaction of aqueous sodium carbonate with aqueous iron(iii) chloride? e) CO 3 2- (aq) + Cl - (aq) CO 2 (g) + Cl 2 O(s) 20. Dinitrogen trioxide, a blue solid, dissociates to form nitrogen monoxide and nitrogen dioxide gases. What mass of nitrogen dioxide is formed from the decomposition of 13.1 g of N 2 O 3?

2 21. Magnesium reacts with iodine gas at high temperatures to form magnesium iodide. What mass of MgI 2 can be produced from the reaction of 4.44 g Mg and 13.4 g I 2? 22. If g MgCl 2 is dissolved in enough water to make ml of solution, what is the molarity of the magnesium chloride solution? 23. A ml sample of NaOH is titrated with ml of M HCl. What is the concentration of the NaOH solution? 24. The thermochemical equation for the combustion of hexane is shown below. C 6 H 14 (g) + 19/2 O 2 (g) 6 CO 2 (g) + 7 H 2 O(g) ΔH = kj What is the enthalpy change for the combustion of 2.50 g C 6 H 14? 26. If 46.1 g Zn at 18.0 C is placed in 80.0 g H 2 O at 75.0 C, what is the final temperature of the mixture? The specific heat capacities of zinc and water are J/g K and J/g K, respectively. 27. What is the wavelength of radiation that has a frequency of s 1? 28. The of a photon of light is proportional to its frequency and proportional to its wavelength. 29. What is the energy in joules of a mole of photons associated with red light of wavelength nm? 30. Which of the following types of experiments demonstrate that an electron has the properties of a particle? a) nuclear fission b) electron diffraction c) light emission from atomic gases d) mass spectroscopy e) photoelectric effect 31. Which of the following sets of quantum numbers refers to a 4p orbital? a) n = 1, l = 1, m l = -1 b) n = 1, l = 2, m l = -1 c) n = 4, l = 1, m l = 0 d) n = 4, l = 2, m l = -1 e) n = 4, l = 3, m l = All of the following sets of quantum numbers are allowed EXCEPT a) n = 6, l = 0, m l = +1 b) n = 5, l = 4, m l = 0 c) n = 4, l = 1, m l = -1 d) n = 3, l = 2, m l = +2 e) n = 1, l = 0, m l = Which of the following diagrams represent p-orbitals? (I) (II) (III) (IV) a) (I) only b) (II) only c (III) only d) (IV) only e) (I) and (II) 34. The Pauli exclusion principle states that a) no two electrons in an atom can have the same spin. b) electrons can have either ±½ spins. c) electrons with opposing spins are attracted to each other.

3 d) no two electrons in an atom can have the same four quantum numbers. e) atoms with no unpaired electrons are diamagnetic. 35. Which element has the electron configuration 1s 2 2s 2 2p 6 3s 2 3p 4? 36. For which of the following atoms is the common ion paramagnetic? a) H b) Al c) Mg d) Ni e) F 37. Which of the following ions have the same ground state electron configuration: Sn 4+, Pb 4+, Sr 2+, and Br -? 38. Which one of the following statements is INCORRECT? a) Ionization energy is always a positive value. b) Ionization energy is the energy required to remove an electron from a gaseous atom. c) For any element, the second ionization energy is larger than the first ionization energy. d) Ionization energy decreases across a periodic of the periodic table. e) Ionization energy decreases down a group of the periodic table 39. In general, atomic radii a) decrease down a group and remain constant across a period. b) decrease down a group and increase across a period. c) increase down a group and increase across a period. d) increase down a group and remain constant across a period. e) increase down a group and decrease across a period. 40. Which combination of atoms is most likely to produce a compound with ionic bonds? a) Al and F b) P and H c) C and O d) Si and O e) S and Br 41. What is the correct Lewis structure for IF 3? 42. Use VSEPR theory to predict the molecular geometry of IF What are the bond angles in ClO 4 -? 44. Which one of the following molecules has a dipole moment? a) CI 4 b) PF 5 c) NCl 3 d) SO 3 e) O How many sigma (σ) bonds and pi (π) bonds are in the following molecule? H H H C C C C H H H a) two σ and nine π b) two σ and seven π c) seven σ and two π d) nine σ and two π 46. What is the hybridization of the sulfur atom in SF 4? 47. How many electrons, protons and neutrons does 87 Sr 2+ have? 48. What is the formula of maganese (VII) oxide?

4 49. What is the empirical formula of the ionic compound that forms between calcium and fluorine? 50. What is the quantity of Fe 2 O 3 that will be produced if 5.00 g of FeS 2 is reacted with 11.0 g of oxygen according to the following reaction: 4 FeS 2 (s) + 11 O 2 (g) --> 2 Fe 2 O 3 (s) + 8 SO 2 (g) 51. The mineral corundum (which is the host structure for sapphires and rubies) has the formula Al 2 O 3. If the density of corundum is 3.97 g/cm 3 how many aluminum atoms are contained in a corundum crystal with a volume of cm 3? 52.Balance the following equation. _ PCl 5 (l) + _ H 2 O(l) --> _ H 3 PO 4 (aq) + _ HCl(aq) 53. Which of the following compounds is not a strong electrolyte? (a) KClO 3 (b) H 2 SO 4 (c) KOH (d) NH 4 Br (e) C 2 H 5 OH 54. If 258 ml of a M AgNO 3 solution is mixed with 500 ml of a M NaCl solution, what is the identity and mass of the precipitate that is formed? 55. Which of the following metals will not dissolve in acid to produce hydrogen gas, H 2? (a) Fe (b) Ag (c) K (d) Both (a) and (c) (e) None of the above Given a chunk of an unknown element you perform the following experiments: If you drop it into a graduated cylinder containing water, the level of the water raises from 50.0 ml to 58.0 ml. Using a digital balance you measure the mass to be g. Using a calorimeter you determine that 1303 J of heat is required to raise the temperature from 25 C to 125 C. Use this information to answer the following two questions: 56. What is the density of this element? 57. What is the specific heat of this element? 58. From the following enthalpies of reaction: 2C 2 H 6 (g) + 7O 2 (g) --> 4CO 2 (g) + 6H 2 O(l) H = kj C(s) + O 2 (g) --> CO 2 (g) H = -394 kj 2H 2 (g) + O 2 (g) --> 2H 2 O(l) H = -572 kj Calculate DH for the following reaction. 2C(s) + 3H 2 (g) --> C 2 H 6 (g)

5 59. Ozone (O 3 ) exothermically decomposes to give oxygen (O 2 ) according to the following reaction: 2O 3 (g) --> 3O 2 (g) H = kj How much heat will be released by the decomposition of 15.0 g of ozone? 60. Increasing the intensity of a light source will have which of the following effects. (a) It will increase the flux (number/sec) of photons being emitted (b) It will increase the energy of the photons being emitted (c) It will increase the frequency of the photons being emitted (d) It will decrease the wavelength of the photons being emitted (e) All of the above 61. What is the proper electron configuration for Fe 3+? 62. How many electrons in a gallium atom (Ga) have a magnetic quantum number m l = 2? 63. What is the wavelength of a photon with an energy of 8.66 x J? 64. Arrange the following atoms in order of increasing first ionization energy: Ne, Ar, S, P, As, Ca. 65. Arrange the following atoms in order of increasing electron affinity: Br, As, Se, Kr. 66. Arrange the following atoms in order of increasing atomic radius: B, Ca, Ga and Cs. 67. Predict which molecule will have the shortest C-O bond? (a) CO 3 2- (b) CO 2 (c) H 2 CO (d) Both (b) and (c) (e) All three, (a), (b) and (c) 68. What is the oxidation state of chlorine in perchloric acid, HClO 4? 69. What is the formal charge on chlorine in the perchlorate ion, ClO 4 -? 70. Estimate H for the reaction between formaldehyde and chlorine to form phosgene and hydrogen : Using the following bond enthalpies as necessary: C O 358 kj/mol H H 436 kj/mol C= O 799 kj/mol C H 413 kj/mol C Cl 328 kj/mol Cl-Cl 242 kj/mol H 2 CO(g) + Cl 2 (g) --> Cl 2 CO(g) + H 2 (g)

6 71. Which of the following ionic compounds would you expect to have the largest lattice energy? (a) KCl (b) RbBr (c) CsI (d) SrSe (e) CaO 72. Which of the following molecules does not violate the octet rule? (a) NO 2 (b) GeF 4 (c) TeF 4 (d) BCl 3 (e) XeF Based on the Lewis dot structures, predict the ordering of N O bond lengths in the following molecules: NO +, NO 2 - and NO Using VSEPR theory, predict the electron domain and molecular geometry of SF Using VSEPR theory, predict the electron domain and molecular geometry of IF What is the hybrid orbital set used by the carbon atom in the molecule H 2 CO? 77. Which of the following molecules is not linear. (a) KrF 2 (b) HCN (c) SO 2 (d) CO 2 (e) both a and c 78. Which of the following molecules are polar? (a) CH 4 (b) CCl 4 (c) CF 4 (d) CH 3 Cl (e) C 2 H Use formal charges to determine the most stable Lewis dot structure for N 2 O. 80. Consider the reaction between Na 2 CO 3 (aq) and MgSO 4 (aq) that results in the formation of solid magnesium carbonate and aqueous sodium sulfate. Include the state of matter for each reaction. Write the complete balanced molecular reaction.(3 pts) Write the complete ionic reaction.(4 pts) Write the net ionic equation.(3 pts) Identify the spectator ion(s).(3 pts)