Azonosító jel: KÉMIA ANGOL NYELVEN EMELT SZINTŰ ÍRÁSBELI VIZSGA május 14. 8:00. Az írásbeli vizsga időtartama: 240 perc

Transcription

1 ÉRETTSÉGI VIZSGA május 14. KÉMIA ANGOL NYELVEN EMELT SZINTŰ ÍRÁSBELI VIZSGA május 14. 8:00 Az írásbeli vizsga időtartama: 240 perc Pótlapok száma Tisztázati Piszkozati EMBERI ERŐFORRÁSOK MINISZTÉRIUMA Kémia angol nyelven emelt szint írásbeli vizsga 1411

2 Important information 240 minutes are allotted for the examination; the work has to be finished after 240 minutes. The questions can be answered in any order. For the solution of the problems, calculators without text-storage capability and four-place logarithm tables can be used. The use of electronic or written support material other than mentioned above is not permitted. Read the introductory text of the questions carefully and keep its instructions. Write the answers in ink. If you cancel an answer or part of an answer, the cancelled work cannot be evaluated. You can get maximum points for the calculations only if the main steps of the solution are also indicated. Please, do not write anything into the grey squares. írásbeli vizsga / május 14.

3 1. Single choice Write the symbol of the single correct answer of each question into the box on the righthand-side of the answers. 1.) Which statement is true for hydronium ion? A) Its shape is triangular. B) It contains 10 protons and 11 electrons. C) It contains delocalised electrons. D) It contains one dative and two sigma bonds. E) It contains one lone electron pair. 2.) Which line contains the molecules in increasing order of bond angle? A) H 2 S, H 2 O, SiH 4, HCN, SO 2 B) H 2 O, H 2 S, SiH 4, HCN, SO 2 C) SO 2, H 2 S, H 2 O, SiH 4, HCN D) H 2 S, H 2 O, SiH 4, SO 2, HCN E) SO 2, H 2 S, HCN, SiH 4, H 2 O 3.) The volume ratio of methane, nitrogen and ethane in gaseous state having equal mass, pressure and temperature is: A) 8 : 7 : 15 B) 8 : 14 : 15 C) 105 : 60 : 56 D) 105 : 120 : 56 E) 1 : 1 : 1 4.) Which line contains ions having only full electron shells? A) Na +, Mg 2+, Al 3+, Cl, O 2 B) Na +, Mg 2+, Al 3+, Cl, S 2 C) K +, Ca 2+, Fe 3+, Cl, O 2 D) Na +, Mg 2+, Al 3+, Zn 2+, O 2 E) Na +, Cu 2+, Al 3+, Br, S 2 5.) Which line shows solutions of equal concentrations in increasing order of ph? A) formic acid, acetic acid, ethanol, sodium formiate, sodium ethoxide B) acetic acid, formic acid, ethanol, sodium ethoxide, sodium formiate C) formic acid, acetic acid, ethanol, sodium ethoxide, sodium formiate D) ethanol, sodium ethoxide, sodium formiate, acetic acid, formic acid E) formic acid, ethanol, acetic acid, sodium ethoxide, sodium formiate 6.) Which carbohydrate contains the highest number of chiral carbon atoms in its cyclic form? A) glucose B) fructose C) sucrose D) maltose E) ribose 6 points írásbeli vizsga / május 14.

4 2. Case study Read the following text carefully, and answer the questions based on your knowledge and the text. The superheavy elements are overhead The synthesis of the element with atomic number 115 (standard temporary name: ununpentium) was already reported in 2004 by a team composed of Russian and an American researchers working in collaboration, but it was needed for the confirmation of the discovery that an independent laboratory repeats the experiment successfully. The confirmation was reported this year, in August by a Swedish research team of the Lund University. The two neighbours of ununpentium are livermorium (Lv) with atomic number 114, confirmed and named last year, and flerovium (Fl) with atomic number 116. The periodic table can be considered closed up to its seventh period with this new announcement. The synthesis of the element temporarily named ununseptium with atomic number 117 was reported by Russian physicists already in 2010; the existence of the element ununoctium with atomic number 118 closing the period (which would have been named eka-radon by Mendeleev) still needs confirmation. This element is expected to behave as a noble gas; it would be a solid non-metal at normal temperature and pressure with density equal to that of mercury, moreover, it would decompose very fast (its half-life is 0.9 ms). Currently, the heaviest element naturally occurring in larger amounts on Earth is uranium with atomic number 92. However, uranium also decays, and it runs out after a long period of time. Nevertheless, the decay of the transuranium elements is faster: the heavier they are, the faster they decompose. As a first approach, the nuclei of the transuranium elements are unstable because the nuclear forces keeping the nucleus together act on short-range but the repelling electrostatic forces act on long-range and they are additive. The so-called Coulombrepulsion acts only among protons, so this explanation would allow the existence of nuclei solely made of neutrons. However, the Pauli Exclusion Principle forbids the presence of identical state nucleons in one nucleus, so the newer neutrons can bind only loosely, which is unfavourable for stability. According to newer theories, it is possible that there exist so-called stability islands among the transuranium elements, when relatively stable elements with adequate proton-neutron ratios can be formed. According to the physicists, the now confirmed ununpentium is on such an island. The transuranium elements have several interesting uses besides the energy production in nuclear power plants. Neptunium, plutonium and americium are theoretically suitable for the production of nuclear weapons, all three having fissionable isotopes. From these, only plutonium was used in bombs due to financial and technological reasons. The bomb dropped at Nagasaki contained plutonium 239. For the detection of high energy neutrons, detectors containing neptunium 237 are used. Americium 241 is used in smoke detectors. The radiation of this isotope ionises the air among the plates of the detector, thus it becomes a conductor. If smoke enters between the plates, the ion current decreases, and the sensor signals. The radiation of curium 242 and 244 is more intense, because half-life of these isotopes is 163 days and 18 years, respectively. Their oxides can be used in radioisotope thermoelectric generators. The space probes sent further from the Sun may use curium 244 as energy source. Curium 244 was already used as radiation source for example in the Mars Exploration Rover. Californium 252 is a strong neutron source; one microgram of it emits 139 million neutrons per minute. Due to this property, it is used as a trigger source in nuclear power plants. (Excerpts of an article published in Origo, Tudomány on 8 th Sept, 2013.) írásbeli vizsga / május 14.

5 a) Give the valence shell electron configuration of ununpentium. b) How would have Mendeleev call ununpentium? c) Define the term isotope. d) How many pieces of each subatomic particle are found in one isotope of the transuranium element used in the smoke detectors? e) According to the article, why are the transuranium elements unstable? f) Which atom does not exhibits Coulomb-repulsion? Give a reason to your answer. g) Unfortunately, there can be found scientific error, inaccuracy. Refine the adjective superheavy appearing (also) in the title. 8 points írásbeli vizsga / május 14.

6 3. Analytical task Consider the following substances: A) carbon monoxide B) carbon dioxide C) formaldehyde D) acetylene E) wood spirits F) soda Answer the questions. More than one answer can be given. a) ) Give the scientific name of the organic molecules. b) Give the letter mark of that substance in the molecule of which all atoms are in one plane. c) Give the letter marks of the non-polar molecules. d) It is gaseous at standard pressure and 25 C. Give the letter mark of the substance for which this statement is not true. e) Give the letter mark of the substance which contains a dative bond in its molecule. Draw the structural formula of the molecule. f) Give the letter marks of the substances reacting with sodium metal. Write down the equation of one of the reactions. g) It produces silver metal from an excess amount of silver nitrate solution also containing ammonia. Write down the equation of the reaction. h) Write down such an equation of a reaction in which B is converted into F. 11 points írásbeli vizsga / május 14.

7 Comparison of aromatic compounds 4. Panel question Benzene Phenol Pyridine Structural formula (indicating bonding and lone electron pairs) State of matter at 100 kpa of pressure and 25 C Strongest secondary bond formed between its molecules Water solubility at room temperature (poor, limited, fully miscible): Equation of the reaction showing the acidity or alkalinity of its aqueous solution: It has the lowest reactivity with bromine. Indicate the equation of the reaction, the conditions, and the name of the organic product: Importance (physiological or uses): points írásbeli vizsga / május 14.

8 5. Experiment analysis On five different watch glasses, the following grey and black powders can be found separately: zinc, graphite, calcium carbide, copper(ii) oxide, iron(ii) sulphide First, dissolution in distilled water was tested, after that approx. 10 percent solution by mass of hydrochloric acid was added to small aliquot samples of substances insoluble in water. During the tests, air was excluded. a) There was only one substance insoluble either in water or in hydrochloric acid. Which was this substance? b) Which one is soluble in a large amount of water? Write down the equation describing this change. Let us examine the substances reacting with hydrochloric acid. c) There was no gas evolution only in one case. Which was this substance? Write down the equation of the reaction. What could be seen if a few drops of the solution made with hydrochloric acid were added to 10 cm 3 ammonia solution? Write down the formula of the particle causing this observation. d) Colourless solution was formed only in one case. Which substance was dissolved in that case? If a plate of metal is immersed into the (still acidic) solution after dissolution, in which case no observation could be made? Give the proper letter mark. A) Zn B) Fe C) Cu D) Al E) Mg írásbeli vizsga / május 14.

9 e) Gas evolved and a coloured solution resulted during the dissolution in hydrochloric acid. Which substance was this? Write down the equation of the reaction. The gas produced during the dissolution in hydrochloric acid is bubbled through yellow (dilute) Lugol s solution. What observation can be made? Write down the equation of the reaction. Precipitation occurs by adding NaOH solution to the solution obtained by dissolution in hydrochloric acid solution. Give the formula and colour of the precipitate. 14 points írásbeli vizsga / május 14.

10 6. Calculation Sodium nitrite found in nitrite containing curing salts gives a nice red colour to meat, and it also intensifies the smoky aroma. As it inhibits the proliferation of microorganisms, the use of curing salt is also allowed with organic food. However, it cannot be considered completely safe. It is a vasodilator, it lowers the blood pressure. Moreover, it can cause suffocation as it blocks the oxygen transport by haemoglobin. The allowed mole ratio of sodium nitrite and sodium chloride in curing salt is between 1 : 200 and 1 : 250. A 100 cm 3 solution was obtained by dissolution of grams of the investigated curing salt. Aliquot samples of cm 3 from the solution are titrated against mol/dm 3 of K 2 Cr 2 O 7 solution in a dilute sulphuric acid containing medium. The titrant consumption was 5.00 cm 3, on average. a) Balance the equation of the reaction indicating the changes in the oxidation numbers. K 2 Cr 2 O 7 + NaNO 2 + H 2 SO 4 = Cr 2 (SO 4 ) 3 + K 2 SO 4 + NaNO 3 + H 2 O b) Calculate whether the mol ratio of sodium chloride and sodium nitrite in the investigated curing salt meets the requirements. Let us consider the curing salt being a mixture of sodium chloride and sodium nitrite. 9 points írásbeli vizsga / május 14.

11 7. Calculation A 10.0 dm 3 -large tank is filled with 387 grams of hexane in gaseous form at a suitable temperature, and the closed tank is heated to 700 C at constant volume. Under these conditions, hexane dissociates to benzene and hydrogen. a) Write down the balanced equation of the thermal dissociation of hexane. b) Calculate the equilibrium constant of the process at 700 C, if 80.0% of hexane was dissociated. c) Calculate the pressure of the mixture at equilibrium. d) In another experiment, the same 387 grams of hexane was filled into the same tank, but this time a certain amount of benzene was mixed with hexane, and the system was heated to 700 C. In this case, 60.0% of hexane was converted. How many grams of benzene was mixed to hexane? 14 points írásbeli vizsga / május 14.

12 8. Calculation and analytical task The mol/dm 3 concentration of the aqueous solution of a chiral monochloro alkanoic acid is percent and percent by mol and mass, respectively. a) Determine the molar mass of the chloroalkanoic acid. b) Determine the density of the solution. c) Give the formula of the chloroalkanoic acid and its scientific name. d) The compound can react with NaOH solution in three different ways. Give each reaction type and mark the constitution of the products accordingly. (If the compound identification was unsuccessful, answer the question taking the 2-chlorobutanoic acid as an example.) 11 points írásbeli vizsga / május 14.

13 9. Calculation Determine the formula of the hydrated metal chloride of which the followings are known. Its metal content is 19.5 percent by mass. Reduction of the total metal ion content of the solution resulted by dissolution of 5.33 gram of the salt requires 19.3 minutes when applying a current intensity of 5.00 A. 11 points írásbeli vizsga / május 14.

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16 maximum points 1. Single choice 6 2. Case study 8 3. Analytical task Panel question Experiment analysis Calculation 9 7. Calculation Calculation and analytical task Calculation 11 Correct use of notations and units 1 Precision of results corresponding to that of the data given in calculations 1 Points of the written exam 100 points achieved correcting teacher Date:... Tasks / Feladatsor achieved score rounded to whole numbers / elért pontszám egész számra kerekítve whole points written in the program / programba beírt egész pontszám correcting teacher / javító tanár notary / jegyző Date / Dátum Date / Dátum írásbeli vizsga / május 14.