AAMC MCAT test 5r

Printing Guide Use this printing guide as a reference to print selected sections of this practice test To print, click the PRINTER icon located along the top of the window and enter one of the following options in the PRINT RANGE section of the print dialog window: To Print Enter Print Range Options Complete Practice Test Click ALL radio button Physical Sciences Section Click PAGES FROM radio button and enter pages to 24 Verbal Reasoning Section Click PAGES FROM radio button and enter pages 25 to 45 Writing Sample Section Click PAGES FROM radio button and enter pages 46 to 48 Biological Sciences Section Click PAGES FROM radio button and enter pages 49 to 72 Periodic Table Click PAGES FROM radio button and enter page to Answer Sheet Click PAGES FROM radio button and enter page 73 to 73 This document has been encoded to link this download to your member account The AAMC and its Section for the MCAT hold the copyrights to the content of this Practice Test Therefore, there can be no sharing or reproduction of materials from the Practice Test in any form (electronic, voice, or other means) If there are any questions about the use of the material in the Practice Test, please contact the MCAT Information Line (202828-0690) MCAT Practice Test 5R Physical Sciences Time: 100 minutes Questions: 1-77 Most questions in the Physical Sciences test are organized into groups, each containing a descriptive passage After studying the passage, select the one best answer to each question in the group Some questions are not based on a descriptive passage and are also independent of each other If you are not certain of an answer, eliminate the alternatives that you know to be incorrect and then select an answer from the remaining alternatives Indicate your selected answer by marking the corresponding answer on your answer sheet A periodic table is provided for your use You may consult it whenever you wish This document has been encoded to link this download to your member account The AAMC and its Section for the MCAT hold the copyrights to the content of this Practice Test Therefore, there can be no sharing or reproduction of materials from the Practice Test in any form (electronic, voice, or other means) If there are any questions about the use of the material in the Practice Test, please contact the MCAT Information Line (202828-0690) Periodic Table of the Elements H He 4.0 10 1.0 Li Be B C N O F Ne 6.9 9.0 10.8 12.0 14.0 16.0 19.0 20.2 11 12 13 14 15 16 17 18 Na Mg Al Si P S Cl Ar 23.0 24.3 27.0 28.1 31.0 32.1 35.5 39.9 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 K Ca Sc Ti V Cr Mn Fe Co Ni Cu Zn Ga Ge As Se Br Kr 39.1 37 40.1 38 45.0 39 47.9 40 50.9 41 52.0 42 54.9 43 55.8 44 58.9 45 58.7 46 63.5 47 65.4 48 69.7 49 72.6 50 74.9 51 79.0 52 79.9 53 83.8 54 Rb Sr Y Zr Nb Mo Tc Ru Rh Pd Ag Cd In Sn Sb Te I Xe 85.5 55 87.6 56 88.9 57 91.2 72 92.9 73 95.9 74 (98) 75 101.1 76 102.9 77 106.4 78 107.9 79 112.4 80 114.8 81 118.7 82 121.8 83 127.6 84 126.9 85 131.3 86 Cs Ba La* Hf Ta W Re Os Ir Pt Au Hg Tl Pb Bi Po At Rn 132.9 87 137.3 88 138.9 89 178.5 104 180.9 105 183.9 106 186.2 107 190.2 108 192.2 109 195.1 197.0 200.6 204.4 207.2 209.0 (209) (210) (222) Fr Ra Ac† Unq† Unp Unh Uns Uno Une (223) (226) (227) (261) (262) 58 (263) 59 (262) 60 (265) 61 (267) 62 63 64 65 66 67 68 69 70 71 Ce Pr Nd Pm Sm Eu Gd Tb Dy Ho Er Tm Yb Lu 140.1 90 140.9 91 144.2 92 (145) 93 150.4 94 152.0 95 157.3 96 158.9 97 162.5 98 164.9 99 167.3 100 168.9 101 173.0 102 175.0 103 * † Th Pa U Np Pu Am Cm Bk Cf Es Fm Md No Lr 232.0 (231) 238.0 (237) (244) (243) (247) (247) (251) (252) (257) (258) (259) (260) Passage I Ammonia can be prepared by the reversible reaction between H2 and N2 in the presence of a mixture of FeO and Al2K2O4 (Reaction 1) under a variety of conditions (Table 1) Reaction Table Equilibrium Concentrations of NH3(g) at Several Temperatures and Pressures Equilibrium concentration of NH3(g) Pressure (% by volume) (atm) at 200°C at 400°C at 600°C at 800°C 15.3 0.44 0.05 0.01 100 80.6 25.1 4.47 1.15 200 85.8 36.3 8.25 2.24 1,000 98.3 80.0 31.5 — NH3 can also be prepared by reacting a metal nitride, such as Mg3N2, with H2O, as summarized by the following unbalanced equation (Reaction 2) Is Reaction exothermic under standard conditions? A) Yes, because heat must be added to initiate the reaction B) Yes, because the standard enthalpy change is negative C) No, because the percent yield of NH3 is greatest at high pressure D) No, because the standard enthalpy change is negative Which of the following graphs best shows the effect of pressure on the equilibrium percentage yield of NH3(g) at 200°C? A) B) → Mg3N2(s) + H2O(l) Mg(OH)2(s) + NH3(g) Reaction Ammonia and ammonium salts are used as commercial fertilizers Ammonium salts are prepared by reacting NH3 with HX (an acid) as shown below (Reaction 3) → NH3(g) + HX(aq) NH4X(s) Reaction C) The approximate electronegativities of several elements are given in Table Table Electronegativities of Several Elements Element Elecronegativity H 2.20 I 2.66 N 3.04 O 3.44 F 3.98 D) Sharing or reproducing this material in any form is a violation of the AAMC copyright The most likely role of the FeO/Al2K2O4 mixture used in Reaction is to: A) increase the rate of the reaction B) increase the equilibrium constant C) provide energy to facilitate the reaction D) lower the pH of the reaction mixture If excess NH3(g) reacts with H2SO4(aq), which of the following compounds can be produced? A) NH4SO4 B) NH4H2SO4 C) NH4(SO4)2 D) (NH4)2SO4 What kind of interactions take place between molecules of the product of Reaction 1? A) Ionic only B) Hydrogen bonding only C) Dipole-dipole only D) Both hydrogen bonding and dipole-dipole Which of the following ions involved in Reaction is the strongest base? A) N3-(aq) B) OH–(aq) C) Mg2+(aq) D) H+(aq) Sharing or reproducing this material in any form is a violation of the AAMC copyright Passage II A large amount of energy is released when the nucleus of an atom disintegrates Nuclear fission of kg of U produces approximately 8.0 × 1013 J, an amount of energy equal to that produced by burning 2.3 × 106 kg of coal A simple model of nuclear disintegration can be used to explain the source of this large amount of energy The nucleus of a U atom contains 92 protons and 146 neutrons in a sphere with a radius of approximately 7.6 × 10–15 m There is a large repulsive force between the positive charges in the nucleus This force is balanced by a short-range attractive force, the strong nuclear force By using a simple model, calculations can be done to find the amount of energy released when a uranium atom fissions The model assumes that the uranium nucleus disintegrates into two spherical fragments, as shown in Figure The repulsive force between the two nuclei is kQ2/d2, where k is Coulomb’s constant and d is the distance between the centers of the nuclei The potential energy of the system of charged nuclear fragments is kQ2/(2r), which is the energy available from this disintegration A value of 3.2 × 10–11 J per atom is obtained by making a calculation for the model uranium atom This value is very close to the experimentally determined value According to the passage, the energy released when an atom splits comes from: A) fast-moving electrons B) the short-range attraction of the nucleons C) mutual attraction of the fragments D) mutual repulsion of the fragments A nucleus splits into two fragments that have equal charge but unequal mass Which of the following is equal for the two fragments as they move apart? A) Magnitude of the force of one fragment on the other B) Magnitude of acceleration C) Speed D) Kinetic energy Based on the passage, why are there no naturally occurring elements that have more protons in their nucleus than uranium does? Figure Nuclear disintegration model The fragments each have radius r, mass m, and charge Q Immediately after separation, their centers are separated by 2r There is a large electrical repulsion between these two fragments that causes them to move apart and gain kinetic energy A) All of the heavier elements have radioactively decayed B) All of the heavier elements are stable C) The range of the strong nuclear force is too short to hold them together D) The heavier elements can be made only in nuclear reactors Sharing or reproducing this material in any form is a violation of the AAMC copyright 10 Which of the following graphs best illustrates how the force between fragments from the fission of a uranium nucleus varies as the fragments move away from each other? A) B) C) D) 11 If they are given enough energy, nuclei of lighter atoms can fuse together Which of the following best explains why this energy is required? A) To overcome the mutual repulsion of the nuclei B) To strip the electrons from the nuclei C) To add electrons to the nuclei D) To overcome the strong nuclear force 12 If a uranium nucleus undergoes fission as shown in Figure 1, as one fragment moves away from the other fragment, it has: A) constant speed B) constant acceleration C) decreasing acceleration D) increasing acceleration Sharing or reproducing this material in any form is a violation of the AAMC copyright Passage III Ozone (O3) is formed in the upper atmosphere by reactions and → O+O Reaction 2: O + O → O Reaction 1: O2 13 A compound that significantly assists in ozone depletion CANNOT be: A) a gas B) a radical precursor C) inert in the lower atmosphere D) inert in the upper atmosphere Because reactions and are photochemically reversible, ozone is removed at a rate that is equal to the rate of its formation, and a steady state concentration is reached Table summarizes the thermodynamic data for the oxygen species involved in ozone formation Table Thermodynamic Properties of Oxygen Oxygen S ∆Hf ∆Gf Species (J/mol·K) (kJ/mol) (kJ/mol) O 161.0 247.5 230.1 O2 205.0 0 O3 238.8 142 163.4 The ozone balance has recently been disturbed, resulting in a net loss of ozone in the upper atmosphere Scientists believe this is due in part to reactions involving chlorofluorocarbons (CFCs) such as CF3Cl Although CFCs are typically inert, they can undergo photolysis in the upper atmosphere and subsequently assist in the decomposition of ozone according to reactions 3–5 → F C· + Cl· Reaction 4: Cl· + O → ClO· + O Reaction 5: ClO· + O → Cl· + O Reaction 3: F3CCl 14 The chlorine atom in Reaction is very reactive because it has: A) an unpaired electron B) an extra electron C) an expanded octet D) a partial negative charge 15 Which of the following is the balanced net reaction that is described by reactions and 5? A) O3 + O → O2 B) O3 + O → O2 C) O3 + Cl· → Cl· + O + O2 D) O3 + ClO· → O2 + Cl· 16 Based on Table 1, which of the following graphs most accurately depicts the free energy changes during the course of reactions and 2? A) 3 B) 2 This mechanism is supported by the fact that periodic increases in ClO· in the upper atmosphere correlate well with times of ozone depletion C) D) Sharing or reproducing this material in any form is a violation of the AAMC copyright 17 According to Table 1, what is ∆S of the following reaction? O3 →3O A) –33.8 J/(mol·K) B) 33.8 J/(mol·K) C) –137.4 J/(mol·K) D) 137.4 J/(mol·K) 18 From reactions 3–5, what can be determined about the relative concentrations of CFCs and O2? A) One equivalent of CFC is required to produce one equivalent of O2 B) One equivalent of CFC is required to produce two equivalents of O2 C) A catalytic amount of CFC can produce much O2 D) The CFC is produced by a catalytic amount of O2 Sharing or reproducing this material in any form is a violation of the AAMC copyright 10 These questions are not based on a descriptive passage and are independent of each other 164 Which of the following properties is associated with the existence of glycine as a dipolar ion in aqueous solution? A) High dipole moment B) High molecular weight C) Low dielectric constant D) Low solubility in water 165 β-D-glucuronide The compound shown above is the β-derivative of the D-glucuronic acid The α-D-glucuronide differs in configuration from the β-derivative at: A) C-1 B) C-2 C) C-3 D) C-4 166 Suppose that the amino acid sequences of a protein such as cytochrome oxidase are compared for a large number of species The greatest number of amino acid differences will most likely be found between members of different: A) phyla B) orders C) species D) families 167 Which of the following recombinant processes depends on the F factor plasmid? A) Transformation B) Transduction C) Conjugation D) Translocation Sharing or reproducing this material in any form is a violation of the AAMC copyright 59 Table Selected Amines and pKa Values of Their Conjugate Acids Passage V The actual yield of an organic reaction in water is often lower than the theoretical yield because of a competing hydrolysis reaction that is pH dependent Equation shows the reaction of acetic anhydride with an aliphatic amine, and equations and show two possible competing reactions that can occur in water Equation Equation 168 What is the pHi for allyl bromide if it reacts with N-methylmethanesulfonamide (pKa 11.79) at a maximum pH of 12.2 to give N-allylmethylmethanesulfonamide? A) 6.30 B) 7.00 C) 12.0 D) 12.6 Equation Chemists have shown that the maximum yield for coupling of an electrophile-nucleophile pair such as the reactants in Equation occurs at a maximum pH (pHmax) given by Equation 4, in which Hi is a characteristic of the electrophile and Ka is the acidity constant of the conjugate acid of the nucleophile pHmax = 1/2(pHi + pKa) Equation Table shows pKa values for the conjugate acids of aniline, benzylamine, valine, and lysine 169 The compound formed by replacing the oxygen atom between the two carbonyl groups in acetic anhydride with an –NH– group is classified as an: A) amide B) imide C) imine D) eneamine 170 Equation can be reversed by: A) heating only B) acidification only C) heating followed by acidification D) acidification followed by heating Sharing or reproducing this material in any form is a violation of the AAMC copyright 60 171 The first step in the mechanism of the reaction shown in Equation is the: A) protonation of a carbonyl oxygen atom by a hydrogen atom from the amino group B) protonation of a carbonyl oxygen atom by a hydrogen atom from water C) attack at a carbonyl carbon atom by the lone pair of electrons on the nitrogen atom of the amino group D) attack at a carbonyl oxygen atom by the lone pair of electrons on the nitrogen atom of the amino group 172 Aniline and benzylamine are both: A) primary amines B) secondary amines C) aromatic amines D) nonaromatic amines Sharing or reproducing this material in any form is a violation of the AAMC copyright 61 Passage VI In the human lung, both alveolar ventilation and pulmonary blood flow are required for the continuous exchange of oxygen and carbon dioxide between alveolar air and alveolar capillary blood Ventilation of the alveoli (VA) results from alternating contraction and relaxation of thoracic respiratory muscles that cause changes in thoracic and lung volumes, alveolar pressure (PA), and intrapleural pressure (IPP, the pressure of the fluid surrounding each lung) The intrapleural cavities surrounding the two lungs are separate IPP is negative relative to atmospheric pressure (P, pressure outside the body) because lung elastic recoil tends to reduce lung volume and the thorax tends to expand The mean pulmonary arterial pressure is only 20 mmHg, compared with a mean aortic pressure of 100 mmHg The lower pressure pulmonary circulation supplies systemic venous blood to alveolar capillaries (Q, the blood flow rate to the lung) In the upright human lung, gravity causes an uneven distribution of VA and Q (Figure 1) because it has different effects on IPP and on alveolar capillary perfusion pressure In an upright (seated or standing) human, IPP is more negative at the apex of the lung than at the base Figure Alveolar ventilation (VA) and lung blood flow (Q) decrease linearly from the lung base to the apex The decrease from base to apex is greater for Q than for VA 173 Pulmonary arterial blood differs from the aortic blood because it has: A) more O2, less CO2, and higher pH B) more O2, more CO2, and higher pH C) less O2, more CO2, and lower pH D) less O2, less CO2, and higher pH 174 Contraction of the diaphragm results in a: A) more negative IPP and inspiration B) more negative IPP and expiration C) more positive IPP and inspiration D) more positive IPP and expiration 175 Air flows out of the lungs when: A) PA

P C) IPP