General Chemistry Past Papers PDF

General Chemistry Past papers 1. What is the frequency of a helium-neon laser light with a wavelength of 632.8 nm? The speed of light is 3.00 × 108 m/s. A) 4.74 × 1014 s-1 B) 4.74 × 105 s-1 C) 2.11 × 10-15 s-1 D) 1.58 × 10-15 s-1 2. How many subshells are there in the shell with n = 6? A) 5 B) 6 C)...

General Chemistry Past papers 1. What is the frequency of a helium-neon laser light with a wavelength of 632.8 nm? The speed of light is 3.00 × 108 m/s. A) 4.74 × 1014 s-1 B) 4.74 × 105 s-1 C) 2.11 × 10-15 s-1 D) 1.58 × 10-15 s-1 2. How many subshells are there in the shell with n = 6? A) 5 B) 6 C) 15 D) 36 3. Which of the following is not a valid set of quantum numbers? A) n = 2, l = 1, ml = 0, and ms = -1/2 B) n = 2, l = 1, ml = -1, and ms = -1/2 C) n = 3, l = 0, ml = 0, and ms = 1/2 D) n = 3, l = 2, ml = 3, and ms = 1/2 4. Of the following, which atom has the largest atomic radius? A) Na B) Cl C) K D) Br 5. Of the following, which element has the highest first ionization energy? A) Cl B) F C) O D) S 6. Which of the following represents the change in electronic configuration that is associated with the first ionization energy of magnesium? A) [Ne]3s13p1 → [Ne]3s1 + e- B) [Ne]3s2 → [Ne]3s13p1 C) [Ne]3s2 → [Ne]3s1 + e- D) [Ne]3s2 + e- → [Ne]3s23p1 7. Which element has the most favorable (most negative) electron affinity? A) Na B) Mg C) O D) Ne 8. What is the general trend in ionization energy and electron affinity values? A) Both decrease as one traverses a period from left to right and both decrease as one descends a group. B) Both decrease as one traverses a period from left to right and both increase as one descends a group. C) Both increase as one traverses a period from left to right and both decrease as one descends a group. D) Both increase as one traverses a period from left to right and both increase as one descends a group. 9. How many lone pairs of electrons are on the P atom in PF3? A) 0 B) 1 C) 2 D) 3 10. What geometric arrangement of charge clouds is expected for an atom that has five charge clouds? A) tetrahedral B) square planar C) trigonal bipyramidal D) octahedral 11. Which of the following is not true? A) The sp3 hybrid orbitals are degenerate. B) An sp3 hybrid orbital may hold a lone pair of electrons. C) An sp3 hybrid orbital may form a sigma bond by overlap with an orbital on another atom. D) An sp3 hybrid orbital may form a pi bond by overlap with an orbital on another atom. 12. The MO diagram below is appropriate for B2. Based on this diagram, B2 A) has a bond order of one and is diamagnetic. B) has a bond order of one and is paramagnetic. C) has a bond order of two and is diamagnetic. D) has a bond order of two and is paramagnetic. 13. Use the following MO diagram for Be2, Be2+, and Be2-. Based on this diagram, A) Be2+ is more stable than Be2, and Be2 is more stable than Be2-. B) Be2- is more stable than Be2, and Be2 is more stable than Be2+. C) Be2+ and Be2- are both more stable than Be2. D) Be2 is more stable than either Be2+ or Be2-. 14. At a constant pressure of 1.50 atm what is the enthalpy change ΔH for a reaction where the internal energy change ΔE is 58.0 kJ and the volume increase is 12.6 L? (1 L·atm = 101.325 J.) A) 39.1 kJ B) 56.1 kJ C) 59.9 kJ D) 76.9 kJ 15. The volume of 350. mL of gas at 25°C is decreased to 125 mL at constant pressure. What is the final temperature of the gas? A) -167°C B) 8.9°C C) 70°C D) 561°C 16. At STP how many grams of Mg are required to produce 35 mL of H2 in the reaction shown below? Mg(s) + 2 HCl(aq) → H2(g) + MgCl2(aq) A) 0.035 g B) 0.038 g C) 26 g D) 29 g 17. According to the kinetic molecular theory, the pressure of a gas in a container will decrease if the A) number of collisions with the container wall increases. B) number of moles of the gas increases. C) temperature of the gas decreases. D) volume of the container decreases. 18. Which one of the following gases will have the highest rate of effusion? A) NO2 B) N2O C) N2O4 D) NO3 19. Which is the most exothermic reaction? A) CH4(g) + 2 O2(g) → CO2(g) + 2 H2O(g) B) CH4(g) + 2 O2(g) → CO2(g) + 2 H2O(l) C) CO2(g) + 2 H2O(l) →CH4(g) + 2 O2(g) D) CO2(g) + 2 H2O(g) →CH4(g) + 2 O2(g) 20. Find ΔH for BaCO3 (s) → BaO (s)+ CO2 (g) given 2 Ba (s) + O2 (g) → 2 BaO (s) ΔH = -1107.0 kJ Ba (s) + CO2 (g) + 1/2 O2 (g) → BaCO3 (g) ΔH = -822.5 kJ A) -1929.5 kJ B) -1376.0 kJ C) -284.5 kJ D) 269.0 kJ 21. Use the given standard enthalpies of formation to calculate ΔH° for the following reaction 3 Fe2O3(s) + CO(g) → 2 Fe3O4(s) + CO2(g). A) -5213.4 kJ B) -577.2 kJ C) -47.2 kJ D) +47.2 kJ 22. When a substance melts at its normal melting point, the sign of ΔH is ________ and the sign of ΔS of this phase change is ________. A) +, - B) -, + C) +, + D) -, - 23. For the process: HNO3(g) ⇌ HNO3(l) ΔH° is -39.04 kJ/mol and ΔS° is -111.74 J/(mol ∙ K). What is the normal boiling point of pure HNO3? A) 2.86°C B) 76.2°C C) 270.3°C D) 349.4°C 24. Which of the following compounds has the highest boiling point? A) CH3CH2OH B) HOCH2CH2OH C) H3C-O-CH3 D) CH3CH2CH2CH3 25. Arrange the following in order of increasing boiling point. CH3CH2OH CH3CH2CH3 H3C-O-CH3 CH3CH2NH2 I II III IV A) IV < III < II < I B) II < III < IV < I C) I < IV < III < II D) II < III < I < IV 26. Which of the following forms a molecular solid? A) CaO B) C10H22 C) C(graphite) D) gold 27. What phase changes occur when the temperature is held constant at 140°C and the pressure is increased from 0.25 atm to 1.4 atm? A) gas → liquid → solid B) gas → solid → liquid C) liquid → solid → gas D) solid → liquid → vapor 28. The approximate normal boiling point of this substance is A) 180 K. B) 190 K. C) 300 K. D) 430 K. 29. What is the mole fraction of ethanol in a solution made by dissolving 14.6 g of ethanol, C2H5OH, in 53.6 g of water? A) 0.0964 B) 0.106 C) 0.214 D) 0.272 30. Which of the following statements is true for a supersaturated solution? A) The solute in the solution is at equilibrium with undissolved solute. B) The solution contains more than the equilibrium amount of solute. C) The solution is stable and the solute will not precipitate. D) A supersaturated solution is more than 50% solute by mass. 31. A 0.020 m aqueous solution containing which solute will have the lowest freezing point? A) LiCl B) NaCl C) KCl D) All will have approximately the same freezing point. 32. What is the expected freezing point of a 0.50 m solution of Na2SO4 in water? Kf for water is 1.86°C/m. A) -0.93°C B) -1.9°C C) -2.8°C D) -6.5°C 33. The reaction below is first order in H2 and second order in NO. What is the rate law for this reaction? 2 H2(g) + 2 NO(g) → N2(g) + 2 H2O(g) A) Rate = 2k[H2][NO] B) Rate = k[H2][NO]2 C) Rate = k[H2]2[NO]2 D) Rate = 2k[H2]2[NO]2 34. For a reaction that follows the general rate law, Rate = k[A][B]2, what will happen to the rate of reaction if the concentration of B is increased by a factor of 2.00? The rate will A) decrease by a factor of 1/4.00. B) decrease by a factor of 1/2.00. C) increase by a factor of 2.00. D) increase by a factor of 4.00. 35. The following set of data was obtained by the method of initial rates for the reaction: 2 HgCl2(aq) + C2O42-(aq) → 2 Cl-(aq) + 2 CO2(g) + Hg2Cl2(s) What is the rate law for the reaction? A) Rate = k[HgCl2][C2O42-]-2 B) Rate = k[HgCl2][C2O42-]-1 C) Rate = k[HgCl2]2[C2O42-] D) Rate = k[HgCl2][C2O42-]2 36. For a particular first-order reaction, it takes 48 minutes for the concentration of the reactant to decrease to 25% of its initial value. What is the value for rate constant (in s-1) for the reaction? A) 1.0 × 10-4 s-1 B) 4.8 × 10-4 s-1 C) 6.0 × 10-3 s-1 D) 2.9 × 10-2 s-1 37. Write the equilibrium equation for the forward reaction: 2 CH4 (g) + 3 O2 (g) ⇌ 2 CO (g) + 4 H2O (g) A) Kc = B) Kc = C) Kc = D) Kc = 38. The oxidation of sulfur dioxide by oxygen to sulfur trioxide has been implicated as an important step in the formation of acid rain: 2 SO2(g) + O2(g) ⇌ 2 SO3(g). If the equilibrium partial pressures of SO2, O2, and SO3 are 0.564 atm, 0.102 atm, and 0.333 atm respectively at 1000 K, what is Kp at that temperature? A) 0.292 B) 3.42 C) 5.79 D) 8.11 39. Iron oxide ores are reduced to iron metal by exothermic reaction with carbon monoxide: FeO(s) + CO(g) ⇌ Fe(s) + CO 2 (g) Which of the following changes in condition will cause the equilibrium to shift to the right? A) add FeO B) add CO C) add CO2 D) raise the temperature 40. Which change in the system will drive equilibrium to the left in the reaction below? N2O5(g) ⇌ NO2(g) + NO3(g) A) decrease the amount of NO3 B) increase the amount of N2O5 C) increase the pressure D) increase the volume 41. Which one of the following species acts as a Br∅nsted-Lowry acid in water? A) NaH B) NH4+ C) CH3NH2 D) C6H6 42. Which Br∅nsted-Lowry acid has the strongest conjugate base? A) HBr B) HClO4 C) HF D) HI 43. The following pictures represent aqueous solutions of binary acids of the type HA where the water molecules have been omitted for clarity. Arrange the acids in order of increasing acid strength. A) D < C < A < B B) D < C < B < A C) D < B < A < C D) D < A < C < B 44. What is the pH of a solution prepared by mixing 50.00 mL of 0.10 M NH3 with 25.00 mL of 0.10 M NH4Cl? Assume that the volume of the solutions are additive and that Kb = 1.8 × 10-5 for NH3.3 A) 8.95 B) 9.26 C) 9.56 D) 11.13 45. What is the [CH3CO2-]/[CH3CO2H] ratio necessary to make a buffer solution with a pH of 4.44? Ka = 1.8 × 10-5 for CH3CO2H. A) 0.50:1 B) 0.94:1 C) 1.1:1 D) 2.0:1 46. For whichprocess is the sign of ΔS negative in the system? A) 2 H2(g) + O2(g) → 2 H2O(g) B) 2 H2O(l) + 2 K(s) → 2 K+(aq) +2 OH–(aq) + H2(g) C) H2O(s) → H2O(g) D) H2O(l) → H2O(g) 47. Calculate ΔS° for the following reaction. N2(g) + 2 O2(g) → 2 NO2(g) A) -156.5 J/K B) -121.5 J/K C) 15.5 J/K D) 636.5 J/K 48. For bromine,ΔH°vap = 30.91 kJ/mol and ΔS°vap = 93.23 JK-1mol-1 at 25°C. What is the normal boiling point for bromine? A) 25°C B) 58°C C) 124°C D) 332°C 49. The figure represents the spontaneous deposition of iodine in which iodine vapor, I2(g), becomes crystalline iodine solid I2(s): I2(g): → I2(s). What are the signs (+ or -) of ΔH, ΔS, and ΔG for this process? A) ΔH = +, ΔS = +, ΔG = + B) ΔH = +, ΔS = +, ΔG = - C) ΔH = -, ΔS = -, ΔG = + D) ΔH = -, ΔS = -, ΔG = - 50. What species is oxidized in the reaction: CuSO4(aq) + Fe(s) → FeSO4(aq) + Cu(s)? A) CuSO4 (aq) B) Fe (s) C) FeSO4 (aq) D) Cu (s) 51. What is the shorthand notation that represents the following galvanic cell reaction? Fe(s) + Cu(NO3)2(aq) → Fe(NO3)2(aq) + Cu(s) A) Fe(s) ∣ Fe2+(aq) ∣∣ Cu2+(aq) ∣ Cu(s) B) Cu(s) ∣ Cu2+(aq) ∣∣ Fe2+(aq) ∣ Fe(s) C) Fe(s) ∣ NO3-(aq) ∣∣ NO3-(aq) ∣ Cu(s) D) Cu(s) ∣ Cu(NO3)2(aq) ∣∣ Fe(NO3)2(aq) ∣ Fe(s) 52. A galvanic cell consists of one half-cell that contains Ag(s) and Ag+(aq), and one half-cell that contains Cu(s) and Cu2+(aq). What species are produced at the electrodes under standard conditions? Ag+(aq) + e- → Ag(s) E° = +0.80 V Cu2+(aq) + 2 e- → Cu(s) E° = +0.34 V A) Ag(s) is formed at the cathode, and Cu(s) is formed at the anode. B) Ag(s) is formed at the cathode, and Cu2+ (aq) is formed at the anode. C) Cu(s) is formed at the cathode, and Ag+(aq) is formed at the anode. D) Cu2+(aq) is formed at the cathode, and Cu(s) is formed at the anode.  Module 1 1. For the fourth-shell orbital shown below, what are the principal quantum number, n, and the angular momentum quantum number, l? A. n = 4 and l = 0 B. n = 4 and l = 1 C. n = 4 and l = 2 D. n = 4 and l = 3 E. n = 4 and l = 4 2. Which of the following three sets consists of atoms or ions with the same electron configuration in the ground state? (I) O2-, Ne, and Mg2+ (II) Ni, Cu+, and Zn2+ (III) Clˉ, K+, and Sc3+ A. all three sets B. all but (I) C. all but (II) D. only (I) E. only (III) 3. The following MO diagram is appropriate for N2. Based on this diagram, A. N is diamagnetic and N ˉ is paramagnetic. 2 + 2 B. N and N are both diamagnetic. 2 2 + C. N is more stable than N. 2 + 2 D. N ˉ is more stable than N. 2 2 E. N ˉ and N are both paramagnetic. 2 2 + 4. The geometry associated with sp d hybridization is: 3 2 A. trigonal planar B. linear C. octahedral D. trigonal bipyramidal E. tetrahedral 5. The volume of 350 mL of gas at 25°C is decreased to 125 mL at constant pressure. What is the final temperature of the gas? R = 0.0821 L atm/K mol A. -167°C B. 106°C C. 8.9°C D. 50°C E. -70°C 6. Consider the phase diagram of a pure substance on the right. What happens to a sample of the substance when the temperature is decreased from 250°C to 50°C at a constant pressure of 0.25 atm? A. vaporization B. deposition C. melting D. freezing E. condensation 7. What is the correct order for increasing osmotic pressure of the following aqueous solutions at 25 C? o (a) 0.2 M aluminum chloride; (b) 0.5 M glucose; (c) 0.3 M sodium chloride A. c HClO 2 3 + 4 11. What is the [CH3COO-]/[CH3COOH] ratio necessary to make a buffer solution with a pH of 4.44? Ka = 1.8 × 10-5 for CH3COOH. A. 0.50:1 B. 0.94:1 C. 1.1:1 D. 1.5:1 E. 2.0:1 12. A reaction has ΔH° = -60.9 kJ/mol and ΔS° = 266.6 J/K. Is this reaction spontaneous or nonspontaneous? At what temperature (if any) can the spontaneity be reversed? A. nonspontaneous, can be made spontaneous at 228 K B. nonspontaneous, cannot be made spontaneous at any temperature C. spontaneous, can be made nonspontaneous at 228 K D. spontaneous, cannot be made nonspontaneous at any temperature E. nonspontaneous, can be made spontaneous at 45 K 13. Consider the first-order decomposition of A molecules (shaded spheres) in two vessels of equal volume. What is the half-life of decomposition in vessel (b) relative to the half-life of decomposition in vessel (a)? A. half-life in vessel (b)/half- life in vessel (a) = 4:1 B. half-life in vessel (b)/half- life in vessel (a) = 2:1 C. half-life in vessel (b)/half- life in vessel (a) = 3:2 D. half-life in vessel (b)/half-life in vessel (a) = 1:1 E. half-life in vessel (b)/half- life in vessel (a) = 1:2 14. Using the following standard reduction potentials Fe3+(aq) + e- → Fe2+(aq) E° = +0.77 V Pb2+(aq) + 2 e- → Pb(s) E° = -0.13 V Calculate the standard cell potential for the galvanic cell reaction given below, and determine whether or not this reaction is spontaneous under standard conditions. Pb2+(aq) + 2 Fe2+(aq) → 2 Fe3+(aq) + Pb(s) A. E° = -0.90 V, nonspontaneous B. E° = -0.90 V, spontaneous C. E° = -0.64 V, nonspontaneous D. E° = +0.90 V, spontaneous E. E° = +0.64 V, spontaneous 1. B 2. A 3. E 4. C 5. A 6. B 7. B 8. C 9. B 10. B 11. A 12. D 13. D 14. D  2020 1 SCT general chemistry st 1. According to the Heisenberg uncertainty principle, choose the right statement: A. We can precisely predict both the momentum and the position of the election simultaneously B. We cannot precisely predict both the momentum the position simultaneously C. We can precisely predict the momentum of an electron, or its position, but not simultaneously D. Nor the momentum or the position could be precisely predicted 2. For n=4, the following picture shows the orbital of the atom. What are the 2 quantum numbers fitting this picture? A. n=4 , l=0 B. n=4 , l=1 C. n=4 , l=2 D. n=4 , l=3 3. Which cell will involve a non-spontaneous reaction? A. Galvanic B. Electrolytic cell C. None of them D. Fuel cell E. Concentration cell 4. What is the general trend of ionization energy and electronegativity? A. Both decrease as one transverse to the right and both increase as one descends a group. B. Both decrease as one transverse to the right and both decrease as one descends a group. C. Both increase as one transverse to the right and both decrease as one descends a group. D. Both increase as one transverse to the right and both increase as one descends a group. 5. which one has a larger radius A. K B. CL C. Br D. Na E. N 6. The electronegativity is 2.1 for P and 3 for Cl. According to it we can expect the molecule PCl to 3 be: A. Ionic compound, P will be + Cl will be - B. Ionic compound, P will be - Cl will be + C. Polar covalent bond with partial negative charge at P D. Polar covalent bond and partial positive charge at P E. Non polar 7. 2 elements A and B react. B2+ is formed. Choose the wrong statement: A. B is likely a metal B. The product will be A B 2 C. They will react in the following way 2a+b->a2b D. The radius of A2+ is larger than the radius of A 8. What is correct about VSEPR theory and covalent bonds? A. The bigger the overlap the weaker the bond B. Hybridization of the central atom and geometry are not related C. A pi bond can form from S and P orbitals D. A sigma bond can form from head on overlap of P orbitals 9. Which molecule or ion has a trigonal pyramidal shape for the central atom coordination and the hybridization is sp3? A. CCl 4 B. H20 C. PCl 5 D. NH3 E. CO32- 10. According to molecular orbital theory, and the picture on the right, what is the bond order of F 2 - and is it paramagnetic/ diamagnetic? A. Bond order of 1/2 and diamagnetic B. Bond order of 1.5 and diamagnetic C. Bond order of 1/2 and paramagnetic D. Bond order of 1 and diamagnetic E. bond order of 1 and paramagnetic 11. Which of the following has only dipole dipole moment and London forces? A. BeF3 B. HBr C. HF D. CO2 E. NH3 12. Which compound would have the higher osmotic pressure within a solution A. 0.2M glucose B. 0.3M Ca3(PO4)2 C. 0.2 NaCl D. 0.5 KCl 13. What is the concentration of 171 g glucose (Mw=342 g/mol) in 1000g solution? A. 0.5 M B. 17.1%m C. 1M D. None of them E. 1M 14. What will favor solubility of an ionic solid? A. High lattice E on solid Low hydration E on ions B. High lattice E on solid, high hydration E on ions C. Low lattice E on solid, low hydration E on ions D. Low lattice E on solid, high hydration E on ions E. Mixing 15. Lewis base defined as: A. Electron donor B. Electron acceptor C. Proton donor D. Electron pair donor E. Electron pair acceptor 16. What is the correct answer regarding the molecules:  HCl  HO 2  HO 3 +  Cl - A. Acid: HCl→ conjugate base: H O+ | base: H O→ Conjugate acid: Cl 3 2 - B. Acid: H O → conjugate base: HCl | base: H2O→ Conjugate acid: Cl- 3 + C. Acid: HCl→ conjugate base: Cl | base: H2O→ Conjugate acid: H3O+ - D. Acid: HCl→ conjugate base: H3O+ | base: Cl- → Conjugate acid: H2O E. Acid: H2O→conjugate base: H3O+ | base: HCl → Conjugate acid: Cl- 17. The following pictures represent Aquinas solutions of 2 acids HA (A=X or Y). Water molecules are omitted for simplicity. What is the true statement? A. X- is stronger conjugated base than Y - B. Y- is stronger con base than x- C. Ka of HX is higher than HY D. Kb of HY is higher than HX E. The percent dissociation of X is higher 18. What is the pH of 0.15M HOCl solution (Ka= 3.5×10-8) A. 1 B. 5.9 C. 3.7 D. 4.2 E. 6.8 19. Choose the correct formula for the Henderson Hasselbah: A. pH=Ka + log(H+/HA) B. kA=pH - log(H+/HA) C. pH=pKa + log(A-/HA) D. pH=pKa - log(A-/HA) E. pKa=pH + log(A -/HA) 20. A buffer of acetic acid and sodium acetate has the pH = pKa of acetic acid (4.74). Choose the right answer: A. Upon addition of a small amount of NaOH, the pH decreases slightly B. [CH3COOH] = [ CH3COO-] C. [CH3COOH] < [ CH3COO-] D. [CH3COOH] > [ CH3COO-] E. None of the above are correct 21. Which statement is false A. KF- basic B. CH OONa - basic 3 C. KNO - natural 2 D. AlCl - acidic 3 22. If a system is in constant pressure, delta E is positive and delta H is negative - A. The system loses heat, and decreasing its volume B. The system loses heat and expands C. The system loses heat and expands D. The system loses heat and expands E. System loses/absorbs heat and volume remains unchanged 23. Based on the data: N O 2NO ∆H=57.2 kJ/mol 2 4 2 2NO+O 2NO ∆H=-114.1 kJ/mol 2 2 Calculate ∆H for : 2NO +O N O 2 2 4 A. -17.3 kJ B. 17.3kJ C. 56.9kJ D. -56.9kJ E. -171.1 kJ 24. What is False about Entropy? A. Entropy is state function B. At gas transition phase ∆S =0 C. Pure crystals at T=0K have S=0 D. Spontaneous reaction happens only if the entropy of the system + environment increases. 25. When increasing the concentration of a reactant, the reaction rate goes up. Choose the statement that explains this: A. The kinetic energy of the reactant is higher B. There will be more successful collisions with higher concentration C. The temperature will increase D. The pressure will increase E. The Volume will decrease 26. The rate of the reaction A+2BAB was measured in an experiment. The following table shows 2 the rate in different concentrations. A B V 0.1 0.1 10 -7 0.1 0.2 4*10 -7 0.2 0.2 8*10 -7 What is the rate law? A. V=K[A] [B] 2 B. V=K[A] C. V=K[A] [B] 2 D. V=K[B] E. V=K[A] [B] 27. Which one of the following is the activation energy and the heat of the reaction? A. 1 &3 B. 2&4 C. 2&3 D. 3&1 E. 2&1 28. The reaction A+2BAB is the sum of the elementary equations: 2 A+BAB slow AB+BAB2 fast What is the rate law? A. K[A][ [B]2 B. K[A][B] C. K[A] D. K[B] E. K[A] [B] 2 2 29. What is the name of a colloidal system consisting of liquid continuous medium and liquid dispersed phase? A. Emulsion B. sol C. gel D. foam E. Suspension 30. Which of the following changes will increase the amount of NH 3 in the reaction equilibrium below? 4NH3(g)+5O2(g) 4NO(g)+6H2 O(g) ∆H= -900 kJ/mol A. Decrease the pressure B. Increase the temperature C. Decreasing water vapor pressure D. Removing NO from the tank E. Adding a catalyst 31. For a first order reaction, the half-life of the reaction is 5 minutes. What will be the concentration after 15 minutes if the initial concentration is 4 M? A. A. 0.1 M B. B. 0.5 M C. C. 0.025 M D. D. 0.3 M E. E. 0.25 M 32. What happens when a small amount of NaOH is added to CH 3COOH/ CH3COO- A. the pH is slightly decreased B. the CH3COOH/ CH3COO- Ratio slightly decreased C. the OH- ions reacts with the conjugated base D. the Na+ ion react with the conjugated base E. no change in pH of the solution 33. In a galvanic cell, the cathode is ________ charged, and _________ reaction takes place in it. Choose the right answear: A. Positive, oxidation B. Positive, reduction C. Negative, reduction D. Negative, oxidation 34. The following reaction: Pb (s)+2Ag+Pb2++2Ag(s). ∆G0=-179kJ/mol. (F=96500 C/mol) Calculate the ε of the cell A. 0.92 B. 1.84 C. -0.92 D. -1.84 **There was a question about Hund’s role- which of the following disobeys the rule. Different answers: 2D 3A 4C 11 A 40 A 1. For a given subshell, l=3 ; what is the maximum number of electrons that the subshell can accommodate? A.2 B.4 C.6 D.10 E.14 2. Which statement is TRUE about the following elements: 1 (A=72, Z= 34) ; 2 (A= 74, st nd Z=36), 3 (A=76, Z=38). rd A. The three elements have the same number of protons. B. The three elements have the same number of nucleons. C. The three elements have the same number of neutrons. D. The three elements have the same number of protons + neutrons. E. None of these statements is true. 3. Which of the molecule and geometry assigned to it is not TRUE? A. H20- bent B. CO2- linear C. SCl6- octahedral D. ACl5- trigonal byriamidal E. BF3- trigonal planar 4. Which of the following statement is false? A. None of these statements is false. B. The 1 ionization energy of N is higher than that of O. st C. In the sp² family, the 1 ionization energy is the same for all the elements. st D. The first ionization energy is always smaller than the second ionization energy. E. It’s easier to remove an electron from Na+ than Na 5. We have three gases, O2, N2 and He. Each of them fill a container of 1L. Which of the following statement is TRUE. A. The three gases have the same kinetic energy. B. The three gases are composed of the same number of particles. C. There are twice as molecules in O2 than in N2 and He. D. The three gases have the same density. E. None of these statements is true. 6. Which of the following statements is TRUE? A. None of these statements is true B. Exothermic reactions are always spontaneous. C. Endothermic reactions are always spontaneous. D. Exothermic reactions in which a decrease of entropy occurs are always spontaneous. E. Endothermic reactions in which an increase of entropy occurs are always spontaneous. 7. Which statement is FALSE about voltanic cells? A. They always convert the energy of a spontaneous chemical reaction into electricity. B. The electric spontaneous processes C. Membrane potential in electrocells is always recorded at electrodes D. Anode is positive 8. The order of the reaction of the following reaction: v=k ( )² ( ) is: A. 3 B. 2 C. 1 D. 0 E. ½ 9. Which of the following molecules has not a non-zero entropy at 0°C? A. O2(g) B. Br2(l) C. C(graphite) D. Na(s) E. H202 (l) 10. The statement that no two electrons in the atom have the same four quantum numbers is: a) the lowest energy principle b) the Pauli exclusion principle c) Hund’s rule d) the Heisenberg principle e) Bohr’s law 11. Which of the following forms of electromagnetic radiation has the shortest wavelength? a) radio waves b) infrared c) visible light d) ultraviolet e) microwaves 12. A photon has the frequency 3.90 x 1014Hz. What is the energy of the photon? (Planck’s constant = 6.626 x 10-34 Js) a) 5,88 x 1047 J b) 2,58 x 10-19 J c) 3,88 x 1018 J d) 1,70 x 10-48 J e) 1,18 x 1-5 J 13. Which of the followings does NOT describe a molecule with zero net dipole moment? a) Linear molecule of an element b) diatomic molecule of an element c) trigonal planar molecule, three identical bonds d) CCl4 e) all of these have zero net dipole moment 14. Considering the phase diagram on the right, at a pressure of 1.3 atm and at 20 C this compound exists as: a) a solid and a liquid b) a liquid only c) a solid and a gas d) a solid only e) a liquid and a gas 15. The vapor pressure of a solution containing a nonvolatile solute is directly proportional to: a) molality of the solvent b) osmotic pressure of the solute c) molarity of the solvent d) mole fraction of solvent e) mole fraction of solute 16. If a monoprotic acid, HA is 15% dissociated in a 2.00 M solution, what is its pH a) 0.52 b) 0.30 c) 6.25 d) 1.20 e) 3.33 17. A catalyst: a) actually participates in the reaction b) shifts the equilibrium towards the products c) does not affect a reaction energy path d) always decreases the rate for a reaction e) always increases the activation energy for a reaction 18. In a voltaic cell the electrons enter the solution on the electrode called the ______ , the chemical change that occurs at this electrode is called _________. a) cathode, reduction b) anode, oxidation c) anode, reduction d) cathode, oxidation e) cannot tell unless we know the species being oxidated and reduced 19. Given the following information, which statement is true ? Cu2+(aq) + e- cu+(aq) Ered= 0.34V 2H+(aq) + 2e- H2 (g) Ered= 0.0V Fe2+(aq) + 2e- Fe(s) Ered= -0.44V Ni(s) Ni2+(aq)+ 2e- Ered= 0.34V a. Cu2+(aq) is the strongest oxidizing agent b. Ni(s) is the strongest oxidizing agent c. Fe2+(aq) is the strongest oxidizing agent d. Fe(s) is the strongest oxidizing agent e. H+(aq) is the strongest oxidizing agent 20. given an a theoretical element : AB3 which has one pair of an electrons. what hybridization does it preform? a. Sp b. Sp2 c. Sp3 d. Sp3d e. Sp3d2 23. How many atoms are in one mole of CH3OH? A. 6 B. 6×1023 C. 12×1023 D. 3.6×1024 E. 3 24. Which of the molecule and geometry assigned to it is not TRUE? (NOTE: there is a different from question number 3) A. H2O- bent B. CO2- linear C. SCl6- octahedral D. ACl5- trigonal byriamidal E. NH3- trigonal planar 25. What is the correct electron configuration for the relaxed form of Cl (z=17) A. 1S22S22P53S23P6 B. 1S22S22P73S23P4 C. 1S22S32P53S23P5 D. 1S22S22P63S43P3 E. 1S22S22P 63S23P5 26. Which of the following is the appropriate concerning boiling point A. CH4 < CF4 B. H2 O < H2 S C. HI > HF D. CH3Cl > CH4Cl 27. Which of the following can take part in buffer system? A. Acetic acid sodium acetate B. Acetic acid sodium chloride C. Sodium acetate sodium chloride D. ammonia 28. Which of the following is the best oxidizing agent? A. Cl2 B. I- C. F- D. Zn E. Br2 29. G=-16.2 T=127C H= -17 By this values what is S A. S= 6.3 B. S= -6.3 C. S= -2×10-3 D. S=2×10-3 30. If pH of a solution is 11.30 what is the [OH]? A. 2×10-3 B. 5.2×10-3 C. 5×10-12 D. 7×10-6 31. Which of the following is not a colligative property? A. Vapor pressure depression B. Boiling point elevation C. Freezing point depression D. Solubility E. Osmotic pressure 32. According to the phase diagram given for Compound Y, what description is correct? A. At the temperature and pressure at point 4, Y(g) will spontaneously convert to Y(l). B. At point 3, Y(l) and Y(g) are in equilibrium C. At the pressure and temperature of point 1, Y(s) will spontaneously convert to Y(g) and no Y(l) is possible. D. At the pressure and temperature at point 3, Y(s) Y(g). E. At the temperature and pressure at point 2, Y(l) Y(g) 33. According to the following reaction which statement is correct? HF+H2O H3O+ + F- A. H2O is base B. H2O is acid C. HF is acid and F is conjugated base D. HF is base and H3O is conjugated acid E. ------- 34. Which of the following is the intermediate in the reaction? 2H2O + I- O2 + OI- H2O + OI - H3O+ + I- A. I- B. OI- C. H2 O D. H3 O E. 2H2O 35. If we decrease the pressure and the temperature of a system by factor of 4 what will happen to the volume? A. Decrease by 4 B. Decrease by 16 C. Remain the same D. Increase by 4 E. Increase by 16