Limit hydrocarbons c1 c5 c6 c10. Chemistry. Thematic tests to prepare for the exam. Tasks of a high level of complexity (C1-C5). Ed. Doronkina V.N.
Safronova N. S., Grishantseva E. S., Korobeinik G. S. HYDROCARBON GASES (C1 – C5) AND ORGANIC MATTER OF BOTTOM SEDIMENTS OF THE IVANKOVSK RESERVOIR OF THE VOLGA RIVER // Materials of the V All-Russian. symp. with international participation "Organic matter and biogenic elements in inland waters and marine waters". September 10–14, 2012 Petrozavodsk. – Publishing House of KarRC RAS Petrozavodsk, 2012. – P. 160-164. HYDROCARBON GASES (С1 – С5) AND ORGANIC MATTER OF BOTTOM SEDIMENTS OF THE IVANKOVO RESERVOIR OF THE VOLGA RIVER Safronova N.S. 1, Grishantseva E.S. 1, Korobeinik G.S. 2 1Lomonosov Moscow State University, Department of Geology, GSP-1, Leninskiye Gory, 119991 Moscow, e-mail: [email protected] 2 Institute of Geochemistry and Analytical Chemistry, Russian Academy of Sciences, 119991 Moscow, GSP-1, Kosygina st., 19, e-mail: [email protected] The paper presents the results of a study of the composition of hydrocarbon gases (C1-C5) and determination of the content of total organic matter in the bottom sediments of the Ivankovo reservoir in 1995, 2004 and 2005 (Fig. 1). To study the composition of bottom sediments, we used vapor-phase gas chromatography with a flame ionization detector (Tsvet-500, Russia), instrumental pyrolytic gas chromatography (ROCK-EVAL 2/TOC, FIN BEICIP-FRANLAB, France) and a mass spectrometric method for determining organic carbon δ 13Сorg (Delta S and Delta Plus). Fig.1. Scheme of sampling of bottom sediments of the Ivankovo reservoir. Alignments: 1 - Gorodnya, 2 - Melkovo, 3 - Nizovka-Volga, 4 - Nizovka-Shosha, 5 - Settlement, 6 - Flat, 7 - Konakovo, 8 - Korcheva, 9 - Klintsy, 10 - Dubna. Bays: 11 - Vesna Bay, 12 - Fedorovsky Bay, 13 - Korovinsky Bay, 14 - Redkinsky Canal. The gas field of bottom sediments is very variable in different areas of the reservoir, both in terms of gas saturation and the spectrum of hydrocarbon gases. This testifies to the heterogeneity of the composition of the organic matter of the sediments and to the difference in the conditions of its entry and transformation processes. The heterogeneity of OM determines the different resistance of its components to decomposition and determines the different contribution of the resulting gaseous hydrocarbons to the total composition of the BS gas phase. In gases, saturated hydrocarbons from methane to pentane C1-C5, including i-C4-i-C5 isomers and unsaturated C2-C4 compounds, were identified. The predominant component among the limiting hydrocarbons is methane, it is present in all the studied samples, it accounts for from 75 to 99% of the total content of C1-C5 gases (CH4/C1-C5 limit). Studies have shown (Kodina et al. 2008, Korobeinik 2002) that homologues of methane hydrocarbons of the С2–С3 fraction can be formed as a result of biochemical transformation of terrigenous OM in freshwater river basins, such as the ecosystem of the Ivankovo reservoir. The genesis of hydrocarbons of the С4–С5 fraction can be associated both with terrigenous OM and freshwater plankton, and with technogenic pollution, since pentane opens up the essentially gasoline series of liquid petroleum hydrocarbons. The concentration of methane varies within a fairly wide range from 9610-4 to 2429 10-4 ml/kg, depending on the place and period of sampling. The composition of hydrocarbons in the gas phase of the bottom sediments of the Vidogoshchi, Konakovo, Korchevo and mouth parts of the Moshkovichi Bay, sampled in 1995, is characterized by low concentrations of methane and saturated (limiting) hydrocarbons, the presence of homologues only of the C2 - C3 series. This composition of bottom sediments corresponds to the transformation of organic matter of predominantly natural origin in uncontaminated areas of the reservoir. The composition of hydrocarbon gases in bottom sediments by sections and bays sampled in 2005 has changed. Low concentrations of methane and saturated hydrocarbons of C2-C3 fractions correspond to the Gorodnya, Gorodishche, Plosky, Klintsy gauges, the channel part of the Dubna gauge, and the Vesna, Korovinsky and Peretrusovsky outlets. Characteristic features of the gas composition of the bottom sediments of the Moshkovsky Bay are the high content of methane and the presence of its C2–C5 homologues. In 1995, elevated concentrations of saturated hydrocarbons of the C2-C4 series were detected in this alignment, in 2005 hydrocarbons of the C5 series were discovered. Municipal sewage from the city of Konakovo, as well as industrial waste from the state district power station and other enterprises of the city of Konakovo, enters the Moshkovichi Bay. In the composition of the gases of the Shoshinsky reach near the automobile bridge of the Moscow-St. Petersburg highway, along with high methane contents, concentrations of its homologues up to C5 were also determined. In the bottom sediments of the Nizovka-Shosha section in 2004-2005, hydrocarbons up to C5 were also recorded. This confirms that technogenic pollution from road and rail transport continues to have a negative impact on the ecological state of the reservoir. Most of the samples also contained unsaturated hydrocarbons. Unsaturated hydrocarbons C2-C4 are intermediate products of the destruction of organic matter, they are very reactive due to the instability of the double bond. The presence of these compounds in gases in relatively high concentrations indicates that fresh bioavailable organic matter is constantly supplied to bottom sediments, which is subjected to intensive processing as a result of biodegradation processes, which leads to the constant replenishment of unsaturated hydrocarbons and even their accumulation. In the studied samples, among unsaturated hydrocarbons, ethylene has the highest concentration, its content in a wide range of concentrations, from 2 to 2500 times, exceeds the content of the nearest saturated hydrocarbon, ethane. As an indicator of the intensity of ongoing processes, the value of the ratio of saturated and unsaturated hydrocarbons is used - the coefficient K \u003d C2-C4 pre / C2-C4 unpred. The smaller the value of the coefficient K, the more intense the process of transformation of organic matter. The value of the coefficient K is much less than unity, varies from 0. 003 to 0.49 (at most points up to 0.08), which indicates very active processes occurring in the bottom sediments of the Ivankovo reservoir, although of varying intensity. In 1995, the maximum value of the coefficient K (0.12) was obtained for the bottom sediments of the Plosky gauge, located slightly below the Gorodishche gauge. In 2004-2005, the concentration of ethylene in the samples increased significantly. There are two areas in which the value of the coefficient K increases by an order of magnitude, and, consequently, the intensity of microbiological processes decreases. Bottom sediments sampled in the Gorodnya gauge, downstream from the city of Tver, and in the Gorodishche gauge, at the place of mixing of organic-rich waters of the Shoshinsky reach and polluted waters of the Volga River, downstream of Tver, have the value of this indicator 0.49 and 0.2, respectively. In the Gorodnya site, there is an active accumulation of technogenic organic matter that enters the composition of domestic and industrial waters, the transformation of which is difficult under natural conditions. The Shoshinsky reach drains a swampy area rich in organic matter. Downstream, in the Gorodishche site, the processes of transformation of technogenic organic matter occur more intensively, which is probably associated with the influx of waters from the Shoshinsky reach, enriched with natural organic matter. Comparison of the values of the K coefficients obtained for sediments taken in identical sections in 1995 and 2005 showed that for most of the regions presented, the value of the K coefficients decreased by an average of 2.5 times. In the Moshkovichi Bay, the value of the K coefficient has not changed. This indicates that there has been no improvement in the environmental situation in the area of the Moshkovichi Bay. The exceptions are the Gorodnya and Konakovo gauges, where the value of the K coefficient increased by 8 and 1.5 times, respectively. Thus, if in the Konakovo gauge there is a slight increase in the content of technogenic organic matter, then in the Gorodnya gauge, the accumulation of technogenic organic matter is very significant. This determines not only the level of organic matter content, but indicates the possibility of changing the forms of occurrence and migration ability of heavy metals. Hydrocarbons of the limiting series С4-С5 during the study period were found in different parts of the reservoir: in the areas of Shoshinsky reach and Ploska in 1995; in the districts of Melkovo, Nizovka-Shosha, Plosky and Klintsy in 2004; at the Nizovka-Volga, Nizovka-Shosha, Moshkovichisky Bay and Dubna sites in 2005. In the lower part of the reservoir, located near the city of Dubna, the dam serves as a mechanical barrier, where the speed of the river flow decreases, and as a result, clastic material is deposited, which is accompanied by the accumulation of organic matter, gases are also accumulated here, the origin of which may be associated with terrigenous organic matter. matter and freshwater plankton, which causes high concentrations of all hydrocarbons in the gas phase of sediments. Elevated concentrations of heavy methane homologues characterize samples from the area of the Shoshinsky reach and downstream from the Nizovka-Shoshi gauge. It can be assumed that the increased content of butane and pentane compounds at these points is associated with the technogenic impact on the reservoir of the motor and railway transport of the Moscow-St. Petersburg highway. This is also indicated by the nature of the distribution of hydrocarbon components in the gas phase of bottom sediments. In the early diagenesis of organic matter, the formation of high-molecular hydrocarbons in the process of chemogenic generation is possible. In this case, as a rule, the general regularity in the distribution of components is observed in the process of chemogenic generation: C1>C2>C3>C4>C5. In our case, this pattern is violated due to the increased content of hydrocarbons in the oil series and takes the form: C3<С5, С4<С5. Следует отметить, что повышенное содержание суммы предельных углеводородов (С4, С5 пред) в образцах, отобранных в створах Мелково и Низовка-Волга, объясняется, по-видимому, влиянием другого участка той же автомобильной магистрали, которая проходит вдоль берега р. Волги, выше створа Мелково, а также влиянием поступающих от г.Тверь загрязненных вод. В тоже время в районах города Конаково и Мошковического залива, где значительное влияние на состояние окружающей среды оказывает Конаковская ГРЭС, уровень содержания предельных углеводородов С4, С5 практически не изменился. Таким образом, увеличение в топливном балансе ГРЭС экологически более чистого газового топлива привело к стабилизации экологического состояния окружающих районов, на что указывает не изменяющееся в течение рассматриваемого периода содержание нефтяных углеводородов в донных отложениях водохранилища. Проведенный корреляционный анализ и сопоставление характера кривых распределения концентраций метана в исследуемых образцах в 1995, 2004 и 2005 г.(общее количество проб 67) и концентрацией его более высокомолекулярных гомологов, показывает идентичность, что подтверждает их генетическую связь. Результаты корреляционного анализа показали значимую положительную связь между содержанием метана и суммарным содержанием его гомологов в донных отложениях. Отбор донных осадков для определения содержания ТОС также проводили из основных створов водохранилища. Кроме этого в 2005 году также были отобраны донные отложения в зарастающих водной растительностью заливах. Пробы донных осадков отбирались из-под корней водной растительности. Суммарное содержание органического вещества в твердой фазе донных осадков (ТОС) для исследуемых створов с 1995 по 2005г. изменяется в широком диапазоне, от 0.02 до 29 %, которые генерируют (0.2 -9.9) мг/г породы легких углеводородов (S1). Самые высокие содержания ТОС, от 3% до 29%, получены для заливов, зарастающих водной растительностью. Содержание высокомолекулярных углеводородов и углеводородов крекинга (S2) изменяется в широком интервале (0.1 – 42) мг/г породы, и от 0.3 до 23 мг/г породы варьирует содержание СО2 при крекинге остаточного органического вещества (S3). На образование свободных углеводородов С1- С10 (S1/ТОС) тратится от 5 до 17 % ТОС. Самые высокие значения этой величины (>10%) belong to the Vidogoshcha, Nizovka-Shosha, Babninsky, Moshkovsky and Korovinsky bays. This indicates that the bulk of organic matter (more than 80%) is represented by heavy non-volatile compounds. In the case of autochthonous hydrocarbons, this ratio (S1/TOC) correlates with the parameter S1/S1+S2, which characterizes the degree of implementation of the hydrocarbon potential of organic matter. It should be noted that the high absolute values of the S1 parameter, manifested in the samples of these sections, are a sign of the presence of petroleum hydrocarbons in the upper layers of bottom sediments. The highest values of parameter S1 are observed in the Moshkovsky and Korovinsky bays, as well as in the middle of the Omutninsky insular shallow water. Relatively high values of the T-parameter with a high content of free, including gaseous hydrocarbons, indicates a possible migration of hydrocarbons, and, consequently, the danger of encountering hydrocarbon accumulations in the underlying layers. This is clearly manifested for the Moshkovsky Bay in the place of water discharge from the treatment facilities, the Babninsky, Korovinsky Bays (macrophyte bottom sediments) and the Omutninsky insular shallow water. The value of the HI/OI index, which determines the S2/S3 ratio, can be used to estimate the type of organic matter, its sources, and the nature of transformation. It is possible to distinguish organic matter of algal, planktonogenic and terrigenous origin. Algal kerogen (high S2 and low S3 , HI/OI>1), which obviously depends on the microbiological processes that determine the degree of decomposition of abundantly growing aquatic vegetation in these sections, and is also determined by the physicochemical parameters and the structure of bottom sediments. In the alignments of Ploska, Konakovo, Korcheva, in the stream. M. Peremerki, at the outlet of Moshkovichi Bay, in the channel of the Nizovka-Volga gauge, the degree of maturity of organic matter increases (high S3, low S2, HI/OI<1) и в донных осадках проявляется кероген терригенного происхождения. На примере образцов 2004 года, отобранных в основных створах водохранилища с разным гранулометрическим и литологическим составом, рассмотрим влияние гранулометрического состава на содержание органического вещества в донных осадках. Низкие его значения (0.02-0.6%) характерны для песчаных и супесчаных проб, что на порядок ниже значений ТОС для глинистых и суглинистых проб (1,0-29,0). Минимальные значения ТОС соответствуют пробам, отобранным в районах руч.Перемерки, створов Мелково и Низовка-Волга, которые по гранулометрическому составу идентифицируются соответственно, как супесь легкопесчаная, песок связный мелкозернистый и песок связный крупнозернистый. В створах Перемерки и Низовка-Волга наблюдается минимальное содержание метана и его предельных и непредельных гомологов, что свидетельствует о незначительном поступлении свежего органического вещества. В створе Мелково значительно возрастают концентрации метана и его гомологов, на фоне низкой концентрации ТОС. Это говорит об увеличении доли техногенной составляющей в составе поступающего органического вещества. Значение коэф. К указывает на интенсивный процесс преобразования органического вещества в этих районах водохранилища. Распределение суммарных показателей углеводородов (S1, S2 , S3) в исследуемых пробах идентично распределению ТОС. Данное распределение подтверждается высокими положительными значениями коэффициента корреляции между S1, S2, S3 и ТОС. Однако количественные соотношения индексов НI и ОI в исследуемых пробах отличаются. В донных осадках створа Низовка-Волга, где высокий индекс кислорода, в молекулах органического вещества преобладают кислородные структуры. Кислородные структуры преобладают и в донных осадках створа Мелково, расположенного вблизи створа Низовка-Волга. В створе руч.М.Перемерки более высокий водородный индекс, следовательно, в молекулах органического вещества донных осадков преобладают водородные структуры. В ходе наших исследований впервые были выполнены исследования изотопного состава органического углерода донных отложений Иваньковского водохранилища. Наиболее низкие значения -29 -30%0 характеризуют органический углерод в створах Конаково, Низовка-Шоша, Мелково, Низовка-Волга. Наиболее высокие δ13 С от -26 до -28 характерны для районов Плоски, Клинцы, М.Перемерки. Как говорилось ранее, параметр (HI/OI) определяется соотношением кислородных и водородных атомов в органическом веществе. В терригенном материале содержится много кислородных функциональных групп. Поэтому он обладает низким отношением (HI/OI), при этом терригенное органическое вещество обладает более низкими значениями δ13 С. Это районы Конаково, Мелково и Низовка-Волга (HI/OI<1, δ13 С-29-30%0) - здесь главенствующий процесс поступление терригенного органического вещества. В районах створов Плоски, Клинцы и М.Перемерки в донных осадках накапливается высокоокисленное органическое вещество (HI/OI>1) heavier isotopic composition (HI/OI>1, δ13 С-26…-28%0), which indicates a large contribution of planktonogenic material. The organic matter of the bottom sediments of the M. Peremerka brook also has peculiar geochemical features - equal values of the hydrogen and oxygen indices (HI/OI=1) and the average value of δ13C of all the studied samples -28.77% 0, which is due to the influx of technogenic organic matter in the wastewater water. REFERENCES 1. Kodina L.A., Tokarev V.G., Korobeinik G.S. Vlasova L.N., Bogacheva M.P. Natural background of hydrocarbon gases (C1-C5) of the water mass of the Kara Sea// Geochemistry. 2008. No. 7, pp. 721-733. 2. Korobeinik G.S., Tokarev V.G., Waisman T.I. Geochemistry of hydrocarbon gases in the Kara Sea sediments// Rep.Polar mar.Res. 2002.v.419. p.158-164. 3. Safronova N.S., Grishantseva E.S., Korobeinik G.S. Hydrocarbon gases (С1-С5) and organic matter of bottom sediments of the Ivankovskoye reservoir of the Volga river // Water resources, in print.Figure 1. Scheme of formation of tacheometric survey blocks
Subsequently, individual blocks are connected into a single network. The location of the determined points is calculated in a single coordinate system. At the end of the survey, a mathematical model of the area is compiled, which is stored in the computer memory and can be implemented in the form of a topographic plan.
5.2. Settlement scheme in moves
The coordinates of tie points Хс, Ус and stations Хт, Ут can be calculated from the measured values of horizontal angles 1 and 2, horizontal distances S1, S2, S3, S4, adjoining angle o and coordinates Xa, Yа of the starting point, fig. 2. Their triangle AC1C2 we have:
d 2 = S1 2 + S2 2 - 2S1S2cos1;
sin1 = S2 sin1 / d.;
Xt1 = Xs1 + S4cosc1t1, Yt1 = Уc1 + S4sinc1t1,
where с1т1 = ac1 + (1+2) - 180.
The control of the calculation of coordinates is the repeated determination of the corresponding elements through the angles 3 and 4.
Tie heights are determined by trigonometric leveling. To do this, the inclination angles to tie points should be measured at stations and starting points. The excesses between stations are defined as the sum of two excesses: from the starting point (or the previous station) to the tie point and from it to the determined one.
When processing, it is possible to select the running line A - C1 - T1 - C4 - B, along which to perform the adjustment of the measurement results and calculate the coordinates and heights of the stations. Subsequently, using these coordinates, the coordinates of the pickets are calculated. Thus, a digital model of the area is created, which is subsequently presented in a convenient form for use.
Figure 2. Scheme of the total station
5.3. Reduction of stations to a single coordinate system
In block tacheometry, the orientation of the electronic total station at the station is performed arbitrarily. This leads to the fact that the coordinates of tie points are actually determined in different coordinate systems. If there are two adjacent stations, then in both systems the origin of coordinates is aligned with the instrument installation point, and the direction of the abscissa axes is chosen along the zero stroke of the limb of the horizontal circle. Therefore, the systems will be rotated relative to each other by some angle , fig. 3.
Figure 3. Scheme of connection of coordinate systems of stations
In the coordinate system of point A, the coordinates of tie points are determined by the formulas:
Xc1 = Xa + S1cos1; Yc1 = Ya + S1sin1;
Xc2 = Xa + S2cos2; Yc2 = Ya = S2sin2,
where S1, S2, 1, 2 are measured horizontal distances and corresponding directions.
Similarly, when determining the position of tie points from station B, we have:
ХС1 = Хb + S1cos1; YC1 = Yb + S1sin1;
XC2 = Xb + S1cos2; YC2 = Yb + S2sin2.
To calculate the angle of rotation of coordinate systems, the directional angles of the line C1 - C2 connecting the tie points are determined based on the solution of the inverse geodesic problem and their difference is found:
= 1 - 2,
where:1 - directional angle C1 - C2 calculated at station A,
2 - directional angle C1 - C2 calculated at station B.
The parallel shift of the coordinate system of point B relative to point A is determined by comparing the coordinates of the corresponding points with the same name.
Chemistry. Thematic tests to prepare for the exam. Tasks of a high level of complexity (C1-C5). Ed. Doronkina V.N.
3rd ed. - R. n / D: 2012. - 234 p. R. n / D: 2011. - 128 p.
The proposed manual has been compiled in accordance with the requirements of the new USE specification and is intended to prepare for the unified state exam in chemistry. The book includes tasks of a high level of complexity (С1-С5). Each of its sections contains the necessary theoretical information, analyzed (demonstration) examples of tasks that allow you to master the methodology for performing tasks of Part C, and groups of training tasks by topic. The book is addressed to students in grades 10-11 of educational institutions who are preparing for the Unified State Examination and planning to get a good result on the exam, as well as teachers and methodologists who organize the process of preparing for the exam in chemistry. The manual is part of the educational and methodological complex “Chemistry. Preparation for the Unified State Exam”, which includes such manuals as “Chemistry. Preparation for the USE-2013”, “Chemistry. 10-11 grades. Thematic tests to prepare for the exam. Basic and advanced levels, etc.
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CONTENT
Introduction 3
Question C1. Redox reactions. Corrosion of metals and methods of protection against it 4
Question questions C1 12
Question C2. Reactions confirming the relationship of various classes of inorganic substances 17
Question questions C2 28
SZ question. Reactions confirming the relationship between hydrocarbons and oxygen-containing organic compounds 54
Asking questions HH 55
Question C4. Calculations: masses (volume, amount of substance) of reaction products, if one of the substances is given in excess (has impurities), if one of the substances is given in the form of a solution with a certain mass fraction of the dissolved substance 68
Questions C4 73
Question C5. Finding the molecular formula of a substance 83
Question questions C5 85
Answers 97
Appendix. The relationship of various classes of inorganic substances. Additional tasks 207
Tasks 209
Problem solving 218
Literature 234
INTRODUCTION
This book is designed to prepare you for high-level tasks in general, inorganic and organic chemistry (part C tasks).
For each of the questions C1 - C5, a large number of tasks are given (more than 500 in total), which will allow graduates to test their knowledge, improve existing skills, and, if necessary, learn the factual material included in the test tasks of part C.
The content of the manual reflects the features of the USE options offered in recent years, and corresponds to the current specification. Questions and answers correspond to the wording of the USE tests.
Part C assignments have varying degrees of difficulty. The maximum score for a correctly completed task is from 3 to 5 points (depending on the degree of complexity of the task). Checking the tasks of this part is carried out on the basis of a comparison of the graduate's answer with an element-by-element analysis of the given sample answer, each correctly completed element is estimated at 1 point. For example, in the SZ task, you need to write 5 equations for reactions between organic substances that describe the sequential transformation of substances, and you can only write 2 (suppose the second and fifth equations). Be sure to write them down on the answer sheet, you will get 2 points for the task of SZ and significantly increase your score on the exam.
We hope that this book will help you successfully pass the exam.