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40. Which calculation should be used to determine the mass percent concentration of the final solution (III) with respect to K2SO4? a. (160.0-150.0)/240.0*100% b. 160.0/240.0*100% c. 150.0/240.0*100% d. (240.0-150.0)/(150.0+160.0+240.0)*100% e. (160.0-150.0)/(240.0-160.0)*100% 41. What is the molarity of K2SO4 solution obtained in the final stage (III)? a. 3.76 mol/L b. 0.235 mol/mL c. 0.235 mol/L d. 1.88 mol/mL e. 1.88 mol/L 42. The volume of the final solution (III) is smaller than the sum of the volume of component solvents (water and ethanol). This effect is related to strong interactions between H2O and C2H5OH molecules and different densities of both liquids. The calculated density of C2H5OH is: Questions no. 40-43 ref er to the f ollowing additional inf ormation: The concentration of a solution is a measure of the amount of a solute that has been dissolved in a given amount of a solvent. Toe percent concentration by mass cp, (or weight percent, as it is sometimes called) is defined as the fraction of a solute in a solution multiplied by 100%. Another way of expressing concentration is molarity , cm (molar concentration). Molarity is expressed as the number of moles of a solute per one liter (lL = 1 dm3) of a solution. Note also molality, which tells us the number of moles of a solute dissolved in exactly one kilogram of a solvent. Once the numbers of moles of all components of a solutioll are known (calculated), its concentration can be altematively expressed as the mole fraction, X. lt is defined as the ratio of the number of moles of that component to the total number of moles of all components in the solution. For questions no. 40-43 consider the protocol of preparation of K2S04 solution which is illustrated below with the consecutive steps I, 11, and 111. a. 1.08 g/mL b. 1.00 g/mL c. 0.08 g/mL d. 0.80 g/L e. 0.80 g/mL 43. Assuming that the solution obtained in stage II (see figure above) was diluted with water by triplicating its total volume, the final molarity of the solution is: a. 0.38 mol/L b. 3.80 mol/mL c. 1.14 mol/L d. 0.13 mol/L e. 1.30 mol/L 44. Measured in May 2019, CO2 concentration in the air in Krakow was 420 ppm (parts per million = 1/1,000,000). The number of CO2 molecules in 22.4 dm3 of the air was (Avogadro number is NA = 6.022 x 1023): a. 9.41 x 109 b. 2.53 x 1020 c. 253 d. 420 e. 941 45. The sum of the stoichiometric coefficients of the following redox reaction is: a. 20 b. 30 c. 23 d. 22 e. 17 46. Indicate the oxidant (Ox) and the reductant (Red) for the following redox reactions [choose which row is collect from a-e] Reaction 1 PbO2 + 2H+ + H2O2 ► Pb2+ + 2H2O + 0 2 Reaction 2 PbS +4H 2O2 ► PbSO4 +4H 2O 47. The diagram below depicts a galvanic cell. The first beaker contains an aqueous solution of Fe(NO3)3 (1M) and FeSO4 (1M), and the second beaker has a 1 M solution of CuSO4. After connecting two electrodes (Pt, Cu) and completing the circuit, the following spontaneous electrochemical reaction occurs: a. 2Fe3- + 3Cu0 → 2 Fe0 + 3 Cu2+ b. Fe2+ + Cu0 → Fe0 + Cu2+ c. 2Fe3- + Cu0 → 2Fe2+ + Cu2+ d. The voltometer is showing no reading e. 2Fe2+ + Cu2+ → 2Fe3+ + Cu0 48. Four aqueous solutions were prepared by dissolving 0.1 moles of KCl, NH4Cl, NH3, and SO3 each in 1 dm3 of distilled water. List the substances according to the increasing pH values of the resulting solutions. a. NH3, KCl, NH4Cl, SO3 b. SO3, KCl, NH4Cl, NH3 c. NH4Cl, SO3, KCl, NH3 d. SO3, NH4Cl, KCl, NH3 e. SO3, NH3, NH4Cl, KCl Reaction 1 Reaction 2 Ox Red Ox Red a. H202 Pb02 H20 2 PbS b. Pb02 H202 PbS H202 c. Pb02 H+ PbS H202 d. Pb02 H202 H202 PbS e. H202 H+ H202 PbS04 standard potentials, Eº Pt salt bridge (KCI) Fe3+JFe2+ 49. pH of a fluid secreted in the stomach was measured by titration with NaOH solution. 10 cm3 of 0.005 mol/dm3 NaOH solution was used for neutralization of 5 cm3 of the stomach fluid. pH of the fluid is: a. 2.5 b. 1.0 c. 3.0 d. 2.0 e. 2.3 50. Which of the following curves illustrates the change of the pH during the reaction between a weak acid (for instance acetic acid) and a weak base (for instance ammonia)? Note that a solution of a weak base is added to a solution of a weak acid. 51. What is the formula of copper (II) sulfate (VI) pentahydrate? a. Cu2 (SO4)2 x 5H2O b. Cu2 SO4 x 5H2O c. CuSO4 x 5H2O d. CuSO3 x 5H2O e. Cu2SO3 x 5H2O 52. N/A 53. Which of the following statements is true regarding properties of the elements denoted 1-8 in the scheme above? a. Element 2 has the highest electronegativity of all elements of the periodic table. b. Element 8 has bigger total number of electrons than element 7. c. Atomic mass of element 5 is greater than that of element 6. d. Elements 1, 2, 3 and 4 are all d-block elements. e. Element 7 has higher number of valence electrons than element 6. 54. The electron configuration: is characteristic of? a. element 5 b. element 4 c. element 8 d. element 6 e. element 7 55. Three flasks of equal volume contain argon chlorine and ozone gases respectively. All gases are kept at room temperature and at exactly the same pressure. Which of the statements below is true? a. The number of ozone molecules is one third of the number of chlorine molecules. b. The number of chlorine molecules is twice the number or argon molecules. c. Number of Cl atoms is half that of Ar atoms. d. All three gases contain the same number of atoms. e. The sum of Cl and Ar atoms is equal to the number of O atoms. Questions no. 53-54 utilize this Periodic Table of Elements: - - 6 .~7i 1 8 il:: 56. Consider the reaction of methanol synthesis: CO(g) + 2H2(g) ↔ CH3OH (g) (Δ𝑯 < 𝟎). What change of equilibrium state will the following actions induce? [select the correct row] 57. The equilibrium constant for the reaction A + 2B = C, calculated based on the concentrations of the reactants, equals Kc = 10. In which direction will the reaction proceed when the composition of the reaction mixture is [A] = 2 mol/dm3 , [B] = 1 mol/dm3, [C] = 6 mol/dm3? a. in forward direction, toward synthesis of C b. in backward direction, toward decomposition of C into A and B. c. cannot be judged based on the given data. d. for the given composition, the reaction cannot proceed in any direction. e. the reaction reached equilibrium. Increase of Increase of Increase of Increase of pressure temperature COamount H2 amount a. Shift toward Shift toward product substrates No effect No effect b. Shift toward Shift toward Shift toward Shift toward product substrates product product c. Shift toward Shift toward Shift toward Shift toward substrates product product product d. No effect No effect Shift toward Shift toward product product e. Shift toward Shift toward Shift toward Shift toward substrates substrates product product 58. At the beginning (1) of the reaction, two gases are fed into a container (kept at 430℃) and the following equilibrium (3) is reached: H2 (g) + I2 (g) ↔ 2HI (g). Changes in the concentration of reactants with time (kinetic curves) are shown in the figure below. Which of the following statements best describes the observed changes in the kinetic curves? a. the reaction reaches equilibrium at both points (3) and (5), and the composition of the reaction mixture at those points is the same. b. At point (2) the reaction proceeds at certain rate and the reaction mixture is composed of exactly the same amount of H2, I2, and HI. c. The final stage (5), the yield of the reaction is 100% and the concentrations of the reactants cannot change. d. The action undertaken in point (4) resulted in disturbance of the equilibrium state, but the final concentrations of H2, I2, and HI at point (5) are the same as they would have been if no action at (4) was taken. e. At the beginning (1), only H2 and I2, are present in the container. Equilibrium is reached at (3) and maintained till (4). At point (4), equilibrium is disturbed by feeding the reaction container with extra amount of I2, which leads to overproduction of HI. 59. A student needs to prepare a dilutes solution by mixing the initial concentrated solution of c1 molarity with water. What proportions of the concentrated solution and water should be used to produce a final solution of molarity C2 = C1/5? a. 1 part of concentrated solution and 2 parts of water b. 1 part of concentrated solution and 3 parts of water c. 1 part of concentrated solution and 5 parts of water d. 1 part of concentrated solution and 1 part of water e. 1 part of concentrated solution and 4 parts of water -------HI 60. The diagram below shows the energy changes during a chemical reaction transforming substrates into products (reaction profile). Which of the following is true? a. The reaction is endoenergetic b. The activation energy for the reverse reaction is higher than for the forward reaction. c. ΔE for the forward reaction equals e. d. The reaction is exoenergetic e. ΔE for the reverse reaction equals the difference ΔE = e-a d Organic Chemistry Practice Questions! 61. The figure above resents a line-angle (skeleton formula). Choose the correct molecular formula of Cefaloram assuming that in this mode of presentation carbon atoms appear at the end of each segment, and all carbon atoms are connected with the number of hidden hydrogen atoms corresponding to their valence*: * Valence is the property of an element that determines the number of other atoms with which an atom of the element can combine’ hydrogen and halogens are usually monovalent, oxygen and sulphur divalent, nitrogen and phosphorus trivalent, and carbon tetravalent. a. C18H18N2O5S b. C18H18NO6S c. C18H18N2O6S d. C18H16N2O6S e. C16H16N2O6S 62. N/A 63. N/A 64. N/A 65. N/A 66. N/A 67. N/A 68. What is the correct name of the following compound as per IUPAC rules? a. 4,6-dichloro-2,5,6-trimethyloctane b. 3,5-dichloro-5-ethyl-1,1,4,5-tetramethylpentane c. 3,5-dichloro-1,1,4,5-tetramethylheptane d. 1,3-dichloro-1-ethyl-1,2,5,5-tetramethylpentane e. 3,5-dichloro-3,4,7,7-tetramethylheptane The Cefaloram, the first generation Cephalosporin antibiotic, still raises interest despite having been known relatively long. ºY o o OH 69. Which of the following isomers C11H18 is called: 4-cyclopentylhex-2-yn: Carbon skeletons of organic compounds Carbon skeletons of organic compounds are called be their common names (methane, ethane, propane, and butane) or the names derived from the Latin numbers of carbon atoms in the molecule (pentance, hexane, heptance, octane ... ) and the characteristic endings as shown below: Hydrocarbons Saturated Unsaturated Alkanes AA cycloalkanes Alkenes Alkyn_es arenes ~o A. B. c. D. E. Functional Groups The chemical propertie s of organic compounds depend on the presence of functional groups. The most important of them are listed below together with the characteristic endings in the names of the compounds containing them : Functional Group Class of compound Examples The ending in the name Hydroxyl -OH Alcohols, phenols ~ OH o-OH -ol -0- Ethers /" o~ ether Amino -NH2 (R) Amines ~ NH2 -amine Carbonyl C=O Aldehydes ~ o -al H Carbonyl Ketones ~ -on o Carboxyl -COOH carboxylic acids ~OH -oic acid Ester-COOR Esters ~º~ Alkyl alkanoate Amide - CONH2(R) Amides ~ o NH2 -amide 70. What series of functional groups are present in Cefaloram: a. Hydroxyl, carboxyl, carbonyl b. Carboxyl, hydroxyl, amide c. Carbonyl, ester, carboxyl d. Hydroxyl, amide, carboxyl e. Amide, ester, carboxyl 71. There are many organic compounds that possess more than one functional group. In such case the problem of preference in naming arises. The more oxidized functional groups are usually preferred in naming. The current preference of certain classes of compounds in naming is as follows: acid > ester > aldehyde > ketone > alcohol > amine > alkene > alkyne > alkane > ether > halogen-derivatives Thus the proper named of the below compound is: a. 4-iodohex-2-enol b. 4-iodohex-2-enal c. 3-iodohex-4-enon d. 4-iodohex-2-enon e. 3-iodohex-4-enal H 1 H H N - f s ~ ~ ºy o o o OH o 72. Why is the synthesis of semi fluorinated polymers called green (see the schema above)? a. Because the product obtained has the molecular weight > 100 kDa b. Because it is a catalytic process (with sodium dithionate) c. Because the polymerization can be carried out in the presence of water and oxygen d. Because the products obtained are green-colored. e. Because the product obtained has a fluorine content up to 59 wt % 73. Which statement accurately describes the expression “tunable fluoropolymer scaffold”? a. It has a high molecular weight b. It has the fluorine content up to 59 wt% c. It can split off HI when treated by various bases d. It can be cross-linked under influence of light e. Answers C and D are correct Questions no. 72-75 refer to the following information: Polymers are important applied organic compounds contributing to one of the main branches of the chemical indu stry. They are macromolecules formed from single molecules (monomers), usually by addition or condensation. Read the following text and answer the questions pertaining to it: Fluoropolymers have infiltrated society as coatings and insulators. However , low processability, few opportunitie s for polymer functionalization , and explosi ve monomers hampering academic investigation of these material s have precluded the exten sion of the unique propertie s of perfluorocarbon s to the cutting edge of material science. Here , we present semifluorinated iodo-ene polymer s as a scaffold to overcome fluoropol ymer limitations . A sodium dithionate initiated polymerization of perfluorodiodides and dienes allows for high-molecular-weight polymers (> 100 kDa) to be prepared in the presence of oxygen and water with up to 59% wt % fluorine content. These conditions are sufficiently mild to enable the polymerization of functional dienes , leading to biodegradable fluoropolymer s . Toe iodo-ene polymerization results in the addition of polarizable iodine atoms , which improve polymer processability ; yet, these atoms can be removed after processing for enhanced stability. Displacement of the iodine atoms with thiols or azides facilitates covalent surface modification and cros s-linking. Finally, the low bond dissociation energy ofthe C-I bond allows allyl group addition as well as photocross- linking. Collectivel y, the simple synthesis and modular nature of the semifluorinated iodo-ene polymers will enable the convergence of perfluorocarbons and advanced materials. (Modular and Proces sable Fluoropolymers prepared via a Safe , Mild Iodo-Ene Polymerisation. ) Fluorine content readily adjustable /"- R~ Mild Green + F F F F F F F F F F F F Modular backbone with increased processability and facile surface modification ► Tuneable fluoropolymer scaff old up to 59% wt% F R Photo-cross linkable 74. Why should the partly fluorinated copolymers be more useful than the traditional fluoropolymers? a. Because they are biodegradable b. Because they have the fluorine content up to 59 wt% c. Because their surface can be modified chemically d. Because they have higher stability caused by possible cross-linking e. Answers A, C, and D are correct. 75. What type of reaction is involved in the preparation of the tunable fluoropolymer scaffold mentioned in the text? a. Addition b. Substitution c. Elimination d. Rearrangement e. Condensation 76.Below, several organic bases are shown. Indicate the sequence ordered by growing basicity. a. 3 < 4 < 2 < 5 < 1 b. 4 < 1 < 3 < 5 < 2 c. 5 < 1 < 2 < 3 < 4 d. 2 < 5 < 3 < 1 < 4 e. 1 < 4 < 3 < 2 < 5 Defining Electron Withdrawing Groups Defining electron withdrawing groups (halogens X, carbonyl, carboxyl group, nitro group), that can lower the electron density of the adjacent atoms, and electron donors (alkyl, hydroxyl, amino group), that can enhance the electron density of the adjacent atoms, is crucial for a better understanding of the relationship between acidity or basicity of organic compounds and their structure. That influence has either an inductive or resonance origin. lnductive effect is based on the difference in electronegativity of the elements, and polarization of bonds drops very quickly with the distance (according to Coulomb 's law). U .N. H,CH3 1 H2 N02-0- NH2 H2 H H2 .. # H3C- ~ - CH3 H3C-C - NH2 H3C-C - N - C - CH3 l. 2. 3. 4. 5. 77. Which of the following heterocyclic bases present in nucleic acids has the lowest percentage content of nitrogen (atomic masses: C = 12 g/mole, H = 1 g/mole, O = 16 g/mole, N = 14 g/mole)? a. 4 b. 5 c. 1 d. 3 e. 2 78. Which of them are structural isomers? a. 1 and 2 b. 1 and 4 c. 1 and 5 d. Answers A and C are correct. e. Answers A, B, and C are correct. NH2 NH2 o o o {~N (¡º Ni: ,H H~3CN,H e < / H 1 N N ~) N NA NH NAO NAO N N / 1 / 2 1 1 H H H H H Adenine Cytosine Guanine Thymine Uracil l. 2. 3. 4. s. Question no. 78 - 80 reder to the following information: Sterioisomers of organic compounds have the same structure (the way the atoms bond with each other) but a different spatial arrangement of atoms . In the molecules with double bond between carbon atoms, where no free rotation is possible , cis!trans or ZJE stereoisomers occur . I in but-2-en (shown below) two methyl groups can be found on the same side of the double bond - > cis or Z isomer or on the opposite sides of the double bond - > trans or E isomer: cis or Z trans or E The structural formulas of sorne organic compounds are shown below : 1 2 3 4 5 79.Which of them depict identical stereoisomers? a. 2 and 5 b. 1 and 4 c. 2 and 4 d. 4 and 5 e. 1 and 2 80.Which of them form a pair of different stereoisomers? a. 2 and 4 b. 2 and 5 c. 1 and 3 d. 3 and 4 e. Answers B and D are correct. 81. a. Four b. Two c. One d. Three e. None 82. In the case of optically active compounds (such as Cefaloram) that are chiral i.e. they have a form of an object and its mirror image (enantiomers), which is dueto the presence of a stereogenic center (or more of them) , a stereogenic centre ( chiral atom) is a carbon atom with four dijferent substituents (also when its constitutes a part of a ring). How many stereogenic centres are present in the following Cefaloram molecule? H º ~)f~ ºY o o OH Below, various Newman projections along C1-C 2 bond of 1-bromo-1-chloro-2-methylpropane are presented. Which of them depict the same stereoisomer? (Remember that in Newman projection 3 substituents at C1 are shown infront of the circle, and 3 substituents at C2 are shown behind the circle. Thefree rotation alone C-C bond is possible and is well depicted by this projection) . H«H:$3: :' :H«: ~*:H3 ~H3 Cl Br H Cl CH3 H CH3 H CH3 1 2 3 4 5 a. 1 and 3 b. 1 and 2 c. 2 and 4 d. 1 and 5 e. Answers A, C and D are correct 83. Of the above Newman projections, which of them depict enantiomers? a. 1 and 5 b. 2 and 4 c. 1 and 3 d. None e. 1 and 2 84. Based on the figure below, indicate the correct sentence: Figure: trendsi n the proportiono f the populationo f Gironaw itht otal,L DL, and HDLc holesterogl reater or lowert hans ornec ut points,a s well as treatedb ecauseo f cholesterolemiian the last 10y ears. Graph( A) presentsm en and (B) women.H DL-Ci ndicatesh igh-densityli poproteinc holestero;l LDL-C, lowd ensity lipoproteinc holesterol. a. In 1995, higher number of men as compared to women had LDL-C level > 130 mg/dL. b. The proportion of population treated because of improper cholesterol level was similar for both men and women over the whole studied period. c. Among men, but not among women, the incidence rate of LDL-C level > 130 mg/dL decreased over the whole observation period. d. The changes in cholesterol in men and women were similar over the last ten years. e. Among women, but not among men, the incidence rate of HDL-C level < 46 mg/dL increased between 1995 and 2000 and then decreased to the previous level. 85. Based on the information from the text above, indicate the FALSE statement(s): [can be more than one] 􀀀 Nowadays, most people can expect to live into their eighties and beyond. 􀀀 As compared to 2015, in 2020 the number of people aged 60 years and older outnumbered children younger than 5 years. 􀀀 By 2050, 80% of older people will be living in low- and middle-income. 􀀀 The pace of population ageing is much slower than in the past. 􀀀 Nowadays, the greatest change in population age structure is observed in highincome countries. People worldwide are living longer. Today, for the first time in history , most people can expect to live into their sixties and beyond . By 2050, the world's population aged 60 years and older is expected to total 2 billion , up from 900 million in 2015. Today, 125 rnillion people are aged 80 years or older. By 2050, there will be almost this many (120 million) living in China alone, and 434 rnillion people in this age group worldwide. By 2050, 80% of all older people will live in low- and middle- income countries. The pace of population ageing around the world is also increasing dramatically. France had almost 150 years to adapt to a change from 10% to 20% in the proportion of the population that was older than 60 years. However , places such as Brazil, China and India will have slightly more than 20 years to make the same adaptation. While this shift in the distribution of a country's population towards older ages - known as population ageing - started in high-income countries (for example in Japan 30% of the population are already over 60 years old), it is now low- and middle-income countries that are experiencing the greatest change. By the middle of the century, many countries for e.g. Chile, China, the Islamic Republic of Iran and the Russian Federation will have a similar proportion of older people to Japann.

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