Chem II Final Exam Questions PDF

1\. How many moles of calcium hydroxide will be neutralized by 2 moles of hydrochloric acid, HCL? A. 0.5 B. 1.5 C. 1.0 D. 2.0 2\. In a titration, 25.0ml of an unknown acid solution, HX (aq), neutralizes 10ml of 0.200 M sodium hydroxide solution, NaOH (eq). What is the concentration of the acid?...

1\. How many moles of calcium hydroxide will be neutralized by 2 moles of hydrochloric acid, HCL? A. 0.5 B. 1.5 C. 1.0 D. 2.0 2\. In a titration, 25.0ml of an unknown acid solution, HX (aq), neutralizes 10ml of 0.200 M sodium hydroxide solution, NaOH (eq). What is the concentration of the acid? A. 0.0400 M B. 0.0800 M C. 0.320 M D. 0.160 M 3\. A 1.2g sample of impure magnesium hydroxide needed 39.3ml of 1.00 mol/L. hydrochloric acid for neutralization in a titration. What is the percent purity of the sample? A. 95 B. 47.5 C. 75 D. None of these 4\. In a titration performed by adding ethanoic acid to sodium hydroxide, which of the following is true? A. The starting pH is below 11 B. The equivalence point is below 7 C. It is not possible to do this titration as there is no clear equivalence point D. The finishing pH is approximately 4 5\. What is the concentration of Iron (II) sulphate if 25.0ml of the solution required 19.8ml of 0.02 mol/L Potassium (VII) manganate for oxidation? A. 0.0792 mol/L B. 0.0158 mol/L C. 0.396 mol/L D. 7.9 x 10-3 6\. A piece of iron wire weighing0.5512g. It is dissolved in acid and the iron it contains is converted to Fe+2, 40.8ml of 0.0400 mol/ L potassium dichromate (K2Cr2O7) is needed to reach the end point when all the solution is titrated. (Use atomic mass iron = 56) products are Cr+3 and Fe+2. The percentage purity of the iron wire is. A. 91.50 B. 99.50 C. 49.75 D. 98.90 E. None of these 7\. An indicator changes color at pH 10. Which of the following titrations could be used for? I)strong acid/strong base II)weak acid/weak base III)weak base/strong acid IV)weak acid/strong base A. I and IV B. I only C. II and III D. None of these 8\. A sample of a monoprotic acid (HA) weighing 0.384g is dissolved in water and the solution is titrated with aqueous NaOH. If 30.0ml of 0.100M NaOH is required to reach the equivalence point, what is the molar mass of HA? A. 37.0 g/mol B. 81.0 g/mol C. 211 g/mol D. 128 g/mol E. 20.3 g/mol 9\. The burning of 3g of carbon to form carbon dioxide releases98.5 kJ of heat. How much heat is released when 2.00 mol of CO2 is produced in a similar reaction? A. 394 kJ B. 197 kJ C. 98.4 kJ D. 788 kJ 10\. In an endothermic reaction the temperature of a 500ml water bath is lowered by 3 K. The heat capacity of the calorimeter is 10 J/K. How much energy was absorbed by the reaction? (Specific heat capacity of water = 4.18 J/g/K)....Remember to look at and pick the correct units\.... A. 6.3 KJ B. 6.3 J C. 6.0 KJ D. 6.0 J 11\. Using the combustion data in the data sheet supplied, the enthalpy of formation of ethanol, C2H5OH in KJ/mol is. A. -1646 B. -246 C. +1646 D. +246 12\. The Standard enthalpy of formation of water is -286 KJ/mol. Find the enthalpy change in KJ which occurs when 1.00kg of hydrogen is burned completely under standard conditions. A. +1.43 x 105 B. -1.43 x 105 C. -7.1 x 105 D. +7.1 x 105 13\. When 50.0ml of 0.500 M HCL at 25.0oC is added to 50.0ml of 0.500 M NaOH at 25.0oC in a coffee cup calorimeter, the temperature of the mixture rises to 28.2oC. What is the heat of reaction per mole of acid? Assume the mixture has a specific heat capacity of 4.18 J/(g x K) and that the densities of the reactant solutions are both 1.00 g/ml. Specific heat capacity of water = 4.18 J/g/K. A. \>100 kJ/mol B. 54 kJ/mol C. 1300 kJ/mol D. 670 kJ/mol E. 27 kJ/mol 14\. A spontaneous reaction will occur at any temperature when. A. ∆H is negative and ∆S is positive B. ∆H is negative and ∆S is negative C. ∆H is positive and ∆S is positive D. ∆H is positive and ∆S is negative 15\. Using the data given, what is the electron affinity of chlorine? KJ/mol Standard enthalpy of atomization of potassium 90 1st ionization energy of potassium 420 Standard bond energy of chlorine 244 Lattice energy of potassium chloride -706 Standard enthalpy of formation of potassium chloride -436 A. -181 KJ/mol B. -484 KJ/mol C. -362 KJ/mol D. ONE ANSWER IS MISSING....YOU HAVE TO FIGURE THIS PROBLEM OUT ON YOUR OWN 16\. Given the data below find ∆Gθ for the following reaction at 373K. Mg(s) + H20(g)  MgO(s) + H2(g) ∆Hfθ KJ/mol Sθ J K-1 mol-1 Mg(s) 0 32.7 H2O(g) -242 188.7 MgO(g) -602 26.9 H2(g) 0 130.6 A. -312 KJ/mol B. -242 KJ/mol C. +242KJ/mol D. -336.17KJ/mol 17\. Calculate the value of ∆H (in KJ/mol) for the reaction using bond energies from your data sheet. N2(g) +3H2(g) ⇌ 2NH3(g) A. -2340 KJ/mol B. +2340 KJ/mol C. +88 KJ/mol D. -88 KJ/mol 18\. The enthalpy change for F2(g)  2F(g) is defined as. A. bond dissociation energy B. atomization energy C. ½ atomization energy D. ½ bond dissociation energy 19\. In which system does randomness decrease? A. Ice melting B. Methane gas crystallizing C. Salt dissolving in water D. Solid iodine subliming E. Liquid alcohol evaporation 20\. Using the enthalpy changes of combustion in your data sheet for this question find the enthalpy change for the following reaction (Enthalpy change for the combustion of liquid benzene C6H6(l) is -3267 KJ/mol). A. +371 B. +201 C. -201 D. -371 21\. For the reaction A + B ⟷ 2C Keq is 16. What fraction of A would remain at equilibrium? A. 1/3 B. 1.6 C. 3/4 D. 2/3 E. There is not enough information to calculate it 22\. A mixture of 1.00 mol of ethanoic acid (CH3COOH) and 1.00 mole water was allowed to reach equilibrium when it was found to contain 0.350 mol of ethanoic acid. CH3COOH + C2H5OH ⟷ CH3COOC2H5 + H2O The equilibrium constant Keq is A.1.22 B.2.62 C. 2.27 D. 4.01 23\. The weak acid HA ionizes as follows: HA(aq) \*\* H+(aq) + A-(aq) In a 0.1 M solution of this acid, pH=4. What is the value of the ionization constant, Ka? A. 1 x 10-6 B. 1 x 10-4 C. 1 x 10-7 D. 1 x 10-1 24\. A mixture of 2.0 mol of CO(aq) and 2.0 mol of H2O(aq) was allowed to come to equilibrium in a 1 L flask at a high temperature in a 1 L flask at a high temperature. If Kc= 4.0. What is the molar concentration of H2(g) in the equilibrium mixture? CO(g) + H2O (g) ⟷ CO2(g) + H2(g) A. 1.0 B. 0.67 C. 1.33 D. 0.75 25\. Which of these is the strongest organic (carboxylic) acid? Acid Ka Formic acid 1.76 x 10-4 Citric acid 7.1 x 10-4 Sulphurous acid 1.2 x 10-2 Phosphoric acid 7.1 x 10-3 A. Phosphoric acid B. Formic acid C. Citric acid D. Sulphurous acid 26\. According to the Bronstead-Lowry concept of acid-base reactions the acids in the equation are: H2O + CO32- ⟷ HCO3- + OH- are A. CO32- and HCO3- B. H2O and CO32- C. H2O and HCO3- D. H2O and OH- E. HCO3- and OH- 27\. Which of the following has an effect on the magnitude of the equilibrium constant? A. Adding more of a reactant B. Adding a catalyst C. Changing the temperature D. Removing products as they are formed E. Increasing the pressure, in a gas phase reaction 28\. For the reaction A + B  C these data were obtained: Experiment Initial Conc: A mol/l Initial Conc: B mol/l Initial Rate of Format of C mol/L/h I 0.10 0.10 0.0300 II 0.10 0.20 0.12 III 0.20 0.20 0.12 A. rate=k\[B\]2 B. rate=k\[A\]2 C. rate=k\[A\]\[B\]2 D. rate=k\[A\]\[B\] 29\. For the reaction X+Y + 2Z  P The mechanism was determined to be 1\) X+Y I (very slow) 2\) I + 2Z P (very fast) What is the rate law for this reaction? A. rate=k\[X\]\[Y\] B. rate=k\[X\]\[Z\] C. rate=k\[X\]\[Y\]\[Z\] D. rate=k\[X\] 30\. For this reaction 3A(g) + 2B(g)  2C(g) + 2O(g) The following data were collected at constant temperature. Determine the correct rate law for this reaction. Trial Initial \[A\] (mol/L) Initial \[B\] (mol/L) Initial Rate (mol/L/min) 1 0.200 0.100 6.00 x 10-2 2 0.100 0.100 1.50 x 10-2 3 0.200 0.200 1.20 x 10-1 4 0.300 0.200 2.70 x 10-1 A. Rate=K\[A\]2\[B\]2 B. Rate=K\[A\]2\[B\] C. Rate=K\[A\]\[B\] D. Rate=K\[A\]1.5\[B\] 31\. The decomposition of SOCL2 is first-order in SOCL2. If the half-life for the reaction is 4.1 hr. How long would it take for the concentration of SOCL2 to drop from 0.36 M to 0.045 M? A. 1.4 hr B. \>40 hr C. 33 hr D. 0.52 hr E. 12 hr 32\. The rate constant for a reaction is 4.65 L mol-1 s-1. What is the overall order of the reaction? A. First B. Zero C. More information is needed to determine the overall order. D. Third E. Second 33\. A first-order reaction has a half-life of 20.0 minutes. Starting with 1.00 x 1020 molecules of reactant at time t = 0. How many molecules remain unreacted after 100.0 minutes? A. 1.00 x 104 molecules B. None of the above C. 5.00 x 1020 molecules D. 3.20 x 1016 molecules E. 2.00 x 1019 molecules 34\. Which one of the following statements is incorrect? A. The rate equation for a reaction 2A + B  C must be rate=k\[A\]2\[B\] B. A reaction A + 2B  C with a rate equation rate=k\[A\]\[B\] must be nulti-step. C. A first order reaction always has a constant half-life. D. Information about the rate of reaction can only be found by experiment. E. A reaction can only occur if the molecules collide with both the activation energy and in the correct orientation. 35\. Which one of the following sets of units is appropriate for a third-order rate constant? A. L mol-1 s-1 B. mol L-1 s-1 C. s-1 D. L2 mol-2 s-1 E. L3 mol-3 s-1 36\. According to valence bond theory, the triple bond in ethyne (C7H7) consists of A. no σ bonds and three π bonds B. one σ bonds and two π bonds C. three σ bonds and no π bond D. two σ bonds and one π bond 37\. Which one of the following statements about orbital is incorrect? A. The carbon atom in C2H2 is sp hybridized. B. The carbon atom in CH4 is sp3 hybridized C. sp hybrid orbitals lie at 180o to each other. D. The nitrogen atom in NH3 is sp2 hybridized. 38\. According to molecular orbital theory the bond order and number of unpaired electrons in Be2+, respectively is: A. 1/2, 0 B. 1, 1 C. 1/2, 1 D. 1, 1/2 39\. The hybridization for the starred carbon atom in the following molecule is: (THERE IS A CARBON COMPOUND WITH SEVERAL DOUBLE & SINGLE BONDS WITH OXYGEN AND HYDROGENS ATTACHED TO IT) A. s2p2 B. sp C. sp2 D. sp3 40\. The geometry for H3O+ is A. square planar B. tetrahedral C. trigonal pyramidal D. rectangular planar 41\. Which molecule would have this shape? (Seesaw Shape) A. SiH4 B. NH4+ C. CCL4 D. SF4 42\. The shape of XeF4 is: A. Tetrahedral B. Square planar C. Rectangular planar D. Trigonal pyramidal 43\. Overlap of atomic orbitals gives a bonding molecular orbital. Which of the following orbital overlaps would NOT result in a sigma bond? (Correct answer would be if this was given is that Px and Py orbitals are lateral, so they can only form pi bonds)....All the answers below form sigma bonds..... 1\. S and S orbital Diagram 2\. S and P in this orientation Diagram 3\. P and P in this orientation Diagram 4\. Sp3 and S Diagram 5\. Sp3 and Sp3 Diagram A. 3,4, and 5 B. 2,3, and 4 C. 3 only D. None of them 44\. A reaction is endothermic and is found to be non-spontaneous at 50oC but is spontaneous at 200oC. What is a suitable explanation for these observations? A. The entropy increases as there is more disorder as the temperature increases. B. The rate of the reaction increases as the temperature increases between the number of collisions between molecules increases. C. The enthalpy of the reaction increases as the temperature increases. D. None of the above 45\. When a catalyst is added to a reaction mixture, it A. Increase the rate of collisions between reactant molecules B. Increases the rate of collisions between reactant molecules C. Slows down the rate of the back reaction D. Provides a new pathway (mechanism) for a reaction. E. None of the above. 46\. Which of the following statements are incorrect? 1\) In an acid base titration, the equivalence point is always at pH=7. 2\) The enthalpy of combustion of oxygen is 0. 3\) A cooling curve can be used to compensate for a poorly insulated reaction vessel. 4\) The reaction that reaction rates usually double when the temperature increases by 10K is because the number of molecules with the activation energy doubles. A. 1 only B. 2,3,4 C. 1 and 2 D. 2 only E. None of them 47\. Which of the following statements is incorrect? A. A primary standard must be standardized before using in a titration. B. Sodium carbonate is a suitable primary standard to titrate against an acid. C. A back titration can be used to find the % of calcium carbonate in a lump of limestone. D. The end point must be at exactly the same pH as the equivalence point. 48\. What was the change in the pH when 2.3g of hydrochloric acid was added to 250ml of a solution containing 0.500 mol/L ethanoic acid and 0.500 mol/L sodium ethanoate Ka of ethanoic acid is 1.77 x 10-5? A. An increase of 0.5 B. A decrease of 0.77 C. A decrease of 0.5 D. An increase of 0.77 49\. Which of the following applies to a chemical equilibrium? I. Forward and reverse reaction rates are equal II\. Equilibrium can be achieved from either direction III\. Properties of the system are constant 50\. Entropy will usually increase when. I. A molecule is broken into two or more smaller molecules. II\. A reaction occurs that results in an increase in the number of moles of gas. III\. A solid changed to a liquid. IV\. A liquid change to a gas. A. IV only B. I only C. I, II, III, and IV D. III only E. II only