Azonosító jel: KÉMIA ANGOL NYELVEN EMELT SZINTŰ ÍRÁSBELI VIZSGA május 13. 8:00. Az írásbeli vizsga időtartama: 240 perc

Transcription

1 ÉRETTSÉGI VIZSGA május 13. KÉMIA ANGOL NYELVEN EMELT SZINTŰ ÍRÁSBELI VIZSGA május 13. 8:00 Az írásbeli vizsga időtartama: 240 perc Pótlapok száma Tisztázati Piszkozati EMBERI ERŐFORRÁSOK MINISZTÉRIUMA Kémia angol nyelven emelt szint írásbeli vizsga 1612

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 fourplace 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 calculation only if the main steps of the solution are also indicated. Please, do not write anything into the grey squares. írásbeli vizsga / május 13.

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4 1. Case study Read the following text carefully, and answer the questions based on your knowledge and the text. Organic matter and water on Mars The Curiosity Mars rover found sources of methane in the atmosphere near the surface, as well as other organic molecules in a sample of a test drilling. The origin of Martian water was also mentioned at the NASA press conference. The on-board laboratory of the Curiosity SAM (Sample Analysis on Mars) measured a large, approximately ten-fold increase in methane concentration several times during the investigation of the gas phase composition of the atmosphere that indicates a local methane source. (These measurements of SAM showed circa 7 ppb of methane concentration, i.e., every 7 th molecule is methane out of one billion molecules in the atmosphere.) In addition, for the first time, Curiosity detected organic matter allegedly of surface origin in a sample taken from a rock d Cumberland. This last finding is an important one because organic matter had already been found in previous samples, but it was always proven that those were contaminations carried there from Earth. However this time, scientists were able to prove credibly that these are Martian molecules. The basics of the operation of the on-board laboratory of SAM is that gaseous substances are produced by heating the rock sample, and this gas can be investigated by its several instruments. Perchlorates (such as sodium perchlorate, NaClO 4 ) present in the surface rocks of Mars make work difficult, as they destroy the possibly occurring complex organic molecules due to their chemical activity. These compounds are also responsible for the fact that the organic molecules present in the Martian rocks mainly occur in the form of chlorine compounds according to the mass spectroscopic results. SAM has detected chlorobenzene while heating the Cumberland rock sample. Organic molecules may indicate the presence of life, however such compounds can originate from simple chemical processes. Although methane is produced mainly by bacteria under Earthian conditions, it can be generated from the cosmic powder falling on Mars affected by UV radiation, but also a mineral called olivine could also have played a role in its formation during the wetter period of the red planet. Olivine (iron magnesium silicate) reacts with water at high temperature (so in the depths) producing considerable amounts of hydrogen gas in a process called serpentinization (according to measurements carried out on Earth, 1 m 3 of olivine may even produce 500 moles of hydrogen). The resulted hydrogen may react with carbon dioxide, the main component of the Martian atmosphere, producing methane and water. However, hydrogen can be produced from water on the surface or in the atmosphere by photochemical degradation (as a result of UV radiation). The Curiosity took sample from the red-coloured surface layer of Mars at Rocknest point first on the 7 th October 2012 by using the scoop system of its robotic arm. During the following weeks, it made four additional scoopings, and the part of the sample collected during the last occasion was successfully introduced into the SAM. For the appearance of water only 300 Celsius degrees was needed. This indicates that water is not entrapped in crystalline substances, rather it is present between the layers of sheet silicate minerals, hydroxide containing ferrominerals, or connected to salt compounds in the surface dust. The displaced sulphur dioxide may primarily originate from sulphate compounds, the source of carbon dioxide can be mainly iron and magnesium containing carbonates. However, the simultaneously forming oxygen implies the presence of a small amount of organic compounds in the sample. According to Laurie Leshin, leader of the research team at Rensselear Polytechnic Institute in New York State, the discovery is important not only from a scientific point of view. Now, we know that there should be plenty of readily accessible water on Mars. When we send humans there, they can collect soil írásbeli vizsga / május 13.

5 anywhere from the surface of the planet, they only have to warm it, and they have water soon, he said. According to the measurements of Curiosity, 10 kg samples taken near the landing place may be enough to produce 200 ml of water. Source: a) Did the measurement of SAM directly prove the presence of organic molecules in the surface rock layer of Mars? Give a reason to your answer. b) Do the measurements of Curiosity prove the presence of microbiological life on Mars? Give a reason to your answer. c) Write the equation of the abiotic (without the contribution of living organisms) formation of methane in the atmosphere of Mars. d) Can we state that olivine plays the role of a catalyst in the formation of methane? Give a reason to your answer. e) Which elements build up olivine? f) The atmosphere of Mars contains oxygen in traces. During which process (also mentioned in the text) is it produced? g) Is it possible, based on the measurements of SAM, that water is present in the form of ice in the surface dust of Mars? Give a reason to your answer. h) Calculate the approximate mass percent of water in the Martian surface dust near the landing place of Curiosity. írásbeli vizsga / május 13.

6 i) One possible component of the Martian surface dust is a mineral called jarosite: KFe 3 (OH) 6 (SO 4 ) 2. Which materials identified during the analysis done at Rocknest point could be originated from jarosite? 9 points 2. Panel question Fill in the empty cells of the table. If a question cannot be answered, indicate it unambiguously with a horizontal line written in the cell. Formula of the compound: General formula of the homologous series of the compound: Name of the compound: The strongest interaction acting between the molecules: State of matter (at 25C, standard pressure): In the case of good solubility in water, acidity/alkalinity of the aqueous solution: Equation of the acid/base reaction happening in aqueous solution: (If there is any.) C 2 H 6 C 2 H 5 OH C 2 H 5 NH points írásbeli vizsga / május 13.

7 3. Analytical task and panel question 14 points Fill in the empty cells of the table so that elementary copper appears as a reactant or product. If there is no reaction, indicate it unambiguously with a horizontal line (or in words) written in the cell. In the three cases indicated, reason shortly why or why not does the reaction happen. Name of the reactants: Copper(II) sulphate solution (electrolysis with graphite electrodes) Name or formula of Equation of the reaction the products: occurring: Cathode process: Anode process: Silver nitrate solution Copper 5. Reason: Zinc(II) sulphate solution Copper Reason: Acetone + copper + water 11. Concentrated nitric acid Nitrogen dioxide Concentrated hydrochloric acid Copper Reason: írásbeli vizsga / május 13.

8 4. Single choice questions Write the symbol of the single correct answer of each question into the box on the righthand-side of the answers. 1. Which property is common both for substances forming either atomic crystal or ionic crystals? A) Their melt conducts electricity. B) They can be elements and compounds, as well. C) They have high melting and boiling points. D) They are insoluble in water. E) Particles at the points of the lattice is held together by secondary chemical bonds. 2. Which statement is false? A) Rate of the endothermic reactions increase if temperature is increased. B) Heat of melting is positive if the absolute value of hydration energy is higher than the absolute value of the heat of crystallisation. C) The sign of reaction heat can be both positive and negative. D) Combustion is always an exothermic reaction. E) Conventionally, a chemical reaction is endothermic, if it needs an energy input. 3. Which element has no allotropic modifications? A) Hydrogen B) Oxygen C) Carbon D) Sulphur E) Phosphorous 4. Which is the compound that cannot be characterised by the following generalised reaction: X-H + Na = X Na + ½ H 2 A) Benzene B) Ethanol C) Formic acid D) Nitric acid E) Water 5. In which line does the oxidation number of the common atom in the compounds increase from left to right? A) KMnO 4, MnO 2, MnSO 4 B) H 2 S, Na 2 S 2 O 3, K 2 SO 4 C) CO, CO 2, CH 4 D) N 2 O 3, NH 3, NO 2 E) NaCl, HClO 4, HOCl írásbeli vizsga / május 13.

9 6. Which of the followings is not a colloid system? A) Milk B) Mayonnaise C) Mineral water D) Egg white solution E) Starch solution 7. Which statement is true? Ozone A) is present only in a few millimetre-thick layer in the upper layers of the atmosphere of Earth, and its effect is negligible because of the thinness of the layer. B) is formed both in the upper and lower layers of the atmosphere. Its presence is useful in both layers. C) is formed in the upper layers of the atmosphere, and it absorbs the majority of UV radiation shorter than 300 nm. It is not present in the lower layers of the atmosphere at all. D) is formed both in the upper and lower layers of the atmosphere, but its presence is harmful in the lower layers of the atmosphere due to its toxicity. E) is formed in the upper layers of the atmosphere by UV radiation, and it causes acid rain upon dissolution in rainwater. 7 points írásbeli vizsga / május 13.

10 5. Experiment analysis There are five test tubes containing five colourless solutions each: aluminium sulphate, barium chloride, silver nitrate, sodium phosphate, and sodium carbonate. In separate test tubes, aliquots of the solutions are mixed pairwise, with one exception. In the case of precipitation, all solid phases formed contain one component. Fill out the empty cells of the table based on the above information. In each cell, write the formula and of the precipitate formed by mixing the solutions indicated in the columns and rows. If there is no precipitation, indicate it with a horizontal line. Solution No. 2 Solution No. 1 formula of the solute aluminium sulphate barium chloride silver nitrate sodium phosphate sodium carbonate formula 7. formula 8. formula aluminium sulphate 9. formula 10. formula 11. formula barium chloride 12. formula 13. formula silver nitrate 14. formula sodium phosphate 12 points írásbeli vizsga / május 13.

11 6. Calculation A smaller flat needs 2500 MJ energy on average for heating per month. Δ f H [H 2 O(l)] = kj/mol, Δ f H [CO 2 (g)] = kj/mol, Δ f H([butane(g)] = kj/mol; A r (H) = 1.000, A r (C) = a) How many kilograms of carbon and butane are needed to be combusted to produce this amount of heat? b) How many m 3 carbon dioxide of 25.00C and standard pressure is emitted in the air in both cases? c) In which case is more carbon dioxide emitted, and how many times is it larger that the amount in the other case? 9 points írásbeli vizsga / május 13.

12 7. Calculation A gas mixture containing acetylene (ethyne) and propylene (propene) is completely combusted with oxygen having six times larger volume and the same pressure and temperature as the mixture. The water-free flue is driven through concentrated sodium hydroxide solution, and the volume of the gas mixture decreases to half (at the same temperature and pressure). For the saturation of the components of the gas mixture having the same amount as used in the reaction above requires dm 3 of hydrogen gas of 25.0C and standard pressure. a) Write the balanced equation of the reactions occurring. b) Calculate the volume percent composition of the ethyne propene gas mixture. c) What was the mass of the ethyne propene gas mixture? 14 points írásbeli vizsga / május 13.

13 8. Calculation g of 11.0 mass percent sodium chloride solution is electrolysed with indifferent electrodes and 32.0 A until the evolution of chlorine stops. a) Write the net reaction taking place in the electrolytic cell. b) How long did electrolysis last? c) What is the mass percent of the solution remaining after electrolysis? d) To what dm 3 should the solution be diluted if a ph = 13.0 solution is needed to be produced from the solution remaining after electrolysis? 14 points írásbeli vizsga / május 13.

14 9. Calculation About 3-4 percent of the population is affected by kidney stones. Kidney stone is a hard, crystalline substance, that is calcium oxalate in the majority of the cases. In order to determine the calcium oxalate content of a 450 mg-piece kidney stone, it was dissolved and cm 3 of stock solution was made from it. Samples of cm 3 each from the stock solution was titrated with mol/dm 3 concentration of potassium permanganate titrant in acidic medium. The average consumption of titrant was 7.20 cm 3. a) Balance the equation taking place. (COOH) 2 + KMnO 4 + H 2 SO 4 = CO 2 + MnSO 4 + K 2 SO 4 + H 2 O b) Calculate the mol concentration (molarity) of the stock solution. c) What is the mass percent of calcium oxalate in the kidney stone? 8 points írásbeli vizsga / május 13.

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16 maximum points 1. Case study 9 2. Panel question Analytical task and panel questions Single choice questions 7 5. Experiment analysis Calculation 9 7. Calculation Calculation Calculation 8 Correct use of notations and units 1 Precision of results corresponding to that of the data given in calculation 1 Points of the written exam 100 points reached correcting teacher Date:... Test/Feladatsor achieved score rounded to whole numbers/elért pontszám egész számra kerekítve whole points written in the program/ programba beírt egész pontszám marking teacher/ javító tanár notary/jegyző date/dátum date/dátum írásbeli vizsga / május 13.