CH 221 GENERAL CHEMISTRY Practice Final Exam Possibly useful information: Avogadro s number = N A = 6.022 x 10 23 particles/mol c = speed of light = 2.998 x 10 8 m/s h = Planck s constant = 6.626 x 10-34 J s 1 cal = 4.184 J 1 J = 1 kg m 2 / s 2 ΔE = - 2.18 x 10-18 1 J 2 1 1 2 n f n i λ =1.10 1 x107 m 1 2 n 1 2 f n i You will need to provide your own periodic table and table of solubility rules for this practice exam.
Page 2 Multiple Choice: Select the one best answer. 1. The dimensions of a rectangular solid are 8.45 cm long, 4.33 cm wide and 2.85 cm high. If the density of the solid is 9.43 g/cm 3, what is its mass? A. 983 g B. 896 g C. 154 g D. 11.1 g E. 1.12 g 2. How many cm 2 are in an area of 4.21 in 2? (1 inch = 2.54 cm, exactly) A. 114 cm 2 B. 27.2 cm 2 C. 10.7 cm 2 D. 1.66 cm 2 E. 1.14 cm 2 3. A radioactive isotope of carbon has the mass number of 14. How many neutrons does this isotope have? A. 12 B. 8 C. 7 D. 6 E. 2 4. The formula of sodium vanadate is Na 3 VO 4 and that of calcium chloride is CaCl 2. What is the formula of calcium vanadate? A. CaVO 4 B. Ca(VO 4 ) 2 C. Ca(VO 4 ) 3 D. Ca 2 VO 4 E. Ca 3 (VO 4 ) 2 5. Which has the greater density, the nucleus of an atom or the whole atom? A. the whole atom B. the nucleus of an atom C. the density of the nucleus is the same as the density of the whole atom 6. What is the formula of sodium perchlorate? A. NaClO D. NaClO 2 B. Na 2 ClO 4 E. NaClO 4 C. Na 2 ClO 7. How many grams of chromium can be produced by the reaction of 44.2 g of chromium(iii) oxide with 35.0 g of aluminum? 2Al + Cr 2 O 3 Al 2 O 3 + 2Cr A. 104 g
Page 3 B. 67.4 g C. 30.2 g D. 15.1 g E. 7.56 g 8. The number of atoms in 9.0 g of aluminum is the same as the number of atoms in A. 24 g of magnesium. B. 18 g of magnesium. C. 12 g of magnesium. D. 9.0 g of magnesium. E. 8.1 g of magnesium. 9. What is the coefficient of H 2 O when the following equation is properly balanced with the smallest set of whole numbers? Al 4 C 3 + H 2 O Al(OH) 3 + CH 4 A. 24 B. 12 C. 6 D. 4 E. 3 10. When 30.0 g of methane reacts completely with excess chlorine to produce 52.0 g of hydrochloric acid, what is the percentage yield? CH 4 + Cl 2 CH 3 Cl + HCl A. 100. % B. 76.0 % C. 42.3 % D. 25.2 % E. 24.0 % 11. 25.0 ml of a solution of citric acid (H 3 C 6 H 5 O 7 ) reacts completely with 15.5 ml of 0.150 M KOH solution. What is the molarity of the oxalic acid solution? A. 1.38 M D. 8.06 x 10-2 M B. 2.42 x 10-1 M E. 3.10 x 10-2 M C. 9.30 x 10-2 M
Page 4 12. Which is true of the equation? 8KI + 9H 2 SO 4 4I 2 + 8KHSO 4 + H 2 S + 4H 2 O A. The oxidizing agent is KI. B. The reducing agent is H 2 S. C. The substance oxidized is sulfur in KHSO 4. D. The substance reduced is sulfur in H 2 SO 4. E. This is not an oxidation reduction equation. 13. How many moles of H + (aq) ions are present in 1.25 L of 0.75 M nitric acid? A. 1.7 mol B. 0.94 mol C. 0.75 mo1 D. 0.60 mol 14. When dilute aqueous solutions of lead(ii) nitrate and potassium bromide are mixed, a precipitate is observed. The products of this reaction are D. PbBr 2 (s) + K + (aq) + NO 3 (aq) B. Br 2 (aq) + NO 2 (g) + PbK 2 (s) C. PbO(s) + K + (aq) + Br (aq) + NO 2 (g) A. Pb 2+ (aq) + Br (aq) + KNO 3 (s) 15. Consider the reaction to form lead(ii) oxide from galena (PbS): 2PbS(s) + 3O 2 (g) 2PbO(s) + 2SO 2 (g) ΔH = -827.4 kj What mass of galena is converted to lead(ii) oxide if 975 kj of heat are liberated? A. 792 g B. 564 g C. 406 g D. 282 g E. 203 g
Page 5 16. Use the following equations to calculate the molar enthalpy of formation for manganese(iv) oxide, MnO 2 (s). 2MnO 2 (s) 2MnO(s) + O 2 (g) MnO 2 (s) + Mn(s) 2MnO(s) ΔH = 264 kj ΔH = -240 kj A. 504 kj B. 24 kj C. -24 kj D. -504 kj 17. In a chemical reaction in which heat is transferred from the system to the surroundings, the reaction is said to be and the sign of q is. A. endothermic, positive B. endothermic, negative C. exothermic, positive D. exothermic, negative 18. The radio station KLCC broadcasts music at 89.7 MHz. Find the wavelength of these waves. A. 2.68 x 10 16 m B. 3.34 x 10 3 m C. 2.68 x 10 2 m D. 3.34 m E. 2.99 x 10-1 m 19. Infrared radiation from the sun has a wavelength of 6200 nm. Calculate the energy of one photon of that radiation. A. 3.2 10-20 J B. 3.2 10-29 J C. 4.l l0-30 J D. 4.l l0-39 J
Page 6 20. Which electron transition in the H atom will result in the emission of the shortest wavelength photon? A. n = 10 n = 3 B. n = 20 n = 2 C. n = 2 n = 1 D. n = 9 n = 8 21. Which wave has the higher frequency? A. A B. B C. both have the same frequency 22. Calculate the frequency of a photon absorbed when the hydrogen atom undergoes a transition from n = 2 to n = 4. A. 8.226 10 14 s -1 B. 6.165 10 14 s -1 C. 2.742 10 6 s -1 D. 2.056 10 6 s -1 23. When intense red light strikes a sample of Cs metal in a photoelectric effect experiment, no electrons are ejected from the surface. In contrast, exciting the sample with weak blue light ejects electrons, whose kinetic energy can be measured. These results can be explained in terms of A. the particle nature of light. B. the wave nature of light. C. the nuclear model of the atom. D. the Heisenberg uncertainty principle. E. the de Brogie wavelength. 24. In a photoelectric effect experiment, a plot of the kinetic energy of the ejected electron vs. incident photon frequency,ν, would look like
Page 7 A. A B. B (ν o = threshold frequency) C. Neither A nor B. The kinetic energy would remain constant at all frequencies. 25. The shape of an atomic orbital is associated with A. the principal quantum number (n) B. the angular momentum quantum number (l) C. the magnetic quantum number (m l ) D. the spin quantum number (m s ) 26. Select the correct set of quantum numbers (n, l, m l, m s ) for the highest energy electron in the ground state of potassium. A. 4, 1, -1, 1/2 B. 4, 1, 0, 1/2 C. 4, 0, 0, 1/2 D. 4, 0, 1, 1/2 27. Select the correct electron configuration for sulfur. A. 1s 2 1p 6 2s 2 2p 6 B. 1s 2 2s 2 2p 6 2d 6 C. 1s 2 2s 2 2p 6 3s 2 3d 4 D. 1s 2 2s 2 2p 6 3s 2 3p 4 28. The electronic structure 1s 2 2s 2 2p 6 3s 2 3p 6 4s 2 3d 8 refers to the ground state of A. Kr B. Ni C. Fe D. Pd E. none of these 29. According to the quantum mechanical model of the atom, in a ground state atom of silver (Ag), how many electrons will there be with the quantum number l = 1? (The n, m l and m s quantum numbers may have any appropriate values.) A. 36 B. 24 C. 18 D. 12 E. 9
Page 8 30. Which of the following is a ground state electron configuration? 31. Based on electron configurations, which of these elements would have chemical behavior most like that of oxygen? A. C B. H C. N D. S E. P 32. In attaining a noble gas electron configuration, alkali metals serve as A. oxidizing agents. C. precipitating agents. B. reducing agents. D. acids.