1. 9 3 p.Little Andrew in the school lab was pouring concentrated (98%) sulfuric acid in the graduated cylinder. After 55 mL of acid were poured into the cylinder, it happened that it felt down and all the acid now was on the flour. Lucily, Andrew had !% "a#$%! solution in the shelf for the neutrali&ation of the acid. 'hat (olume of the soda solution is necessary for complete neutrali&ation of the spilled acid)*ensity of concentrated sulfuric acid is +.8!, g-ml, density of "a#$%! solution is +..! g-ml.2. 9 3 p.+... g of calcium reacted with +... liter of water. 'hich compounds will present in the solution after the reaction) $alculate their mass parts. /olubility of calcium hydro0ide is ..+15 g in +.. g of water.3. 9 7 p.$hemical compounds of an element Q are widely found in the nature. 2his element has no allotropic forms and with o0ygen it forms two compounds A and B with different composition. $ompound A is neutral and in the reactions with binary compounds it may form either acids of bases.$ompound B decomposes in the presence of a catalyst, 3n%4, into the compounds A and Y.'hen compound A reacts with acti(e metals, simple compound X of element Q is formed besides the compounds, which reacts with acids and acidic o0ides.+. 5dentify element Q.4. 'rite the chemical formulas for the compounds A, B, X and Y.!. 'rite the e6uations for the following chemical reactions7a) 8reparation of A,b) 8reparation of base from A,c) 8reparation of acid from A,d) *ecomposition of B in the presence of catalyst 3n%4,e) 9eaction of A with the acti(e metals.4. 9 2 p.$ontent of radon in seawater is 1 +. +9 g-l.#ow many atoms of radon are present in + liter of seawater)5. 9 4 p. Lithium usually is obtained from the mineral spodumen, Li4%:Al4%!:;/i%4, according to the following scheme7a) Spodumen is treated with concentrated sulfuric acid and obtained solution is e(aporated and name these species.4. $alculate the amount of each element in one mole of chlorophyll.!. Aind the molecular formula of chlorophyll.Note: In all the calculations use the atomic weights with the precision of 0.1.9. 9,10 2 p.%n the pans of the scale +.. g +.% sodium hydro0ide solution and +.. g +.% sodium chloride solution were placed. /cale, of course, was in e6uilibrium, but after a while one of the pans started to mo(e down.Which side of the scale will behave more heavier! after a while"Why" #$plain this e$periment.10. 10 11 p. 8urpleCred powdered compound A was boiled with concentrated sulfuric acid. At the beginning gas B (which is (ery good soluble in water) was e(ol(ed. 8recipitate turned to blac and its mass increased roughly by oneCfourth E compound C was formed. After a while precipitate gradually turned almost white and it mass increased roughly twice E compound D was formed. 8recipitate was filtered and water was added to it. Dlue solution was obtained. After e(aporating of this solution, blue crystals of compound E were obtained. 2heir mass was roughly four times higher than that of compound A. #eating of substance E gi(es D. #owe(er, if the heating is continued at higher temperature, compound D con(erts to the compound C and a gas, which contains compound B.Identify all the species mentioned and write the e%uations for all the reactions. #$plain& why compound D is white& but its a%ueous solutions are blue.11. 10 6 p.*eri(e the mathematical formula for calculation the (olume (in normal conditions) of hydrogen e(ol(ed when a grams of magnesium reacts with b grams of sulfuric acid. 8lot this relationship.12. 10,11 6 p. 'hite pigment lithopone consists of barium sulfate and &inc sulfide. 5t may be obtained according to the following scheme7a) Darium sulfide is prepared from barite, Da/%;, by reducing it at high temperatures with carbon mono0ide. b) Finc sulfate is prepared from &inc blend, Fn/, by burning and e(entual treatment with sulfuric acid.'btained solution of (inc sulfate usually contains impurities of iron and manganese species which needs to separated prior to obtaining of lithopone as these metals have colored sulfides. )herefore the following treatment are re%uested:%btained solution is treated with chlorine in wea acidic medium for the o0idation of iron(55) species to the iron(555) and manganese(55) species to the manganese(5=) species. 5n these conditions, iron(555) hydro0ide and manganese(5=) o0ide are precipitated from the solution.c) Lithopone is obtained by mi0ing of barium sulfide with &inc sulfate.Write the e%uations for the chemical reactions.13. 10,11 6 p.5n the following table density of hydrochloric acid solutions is shown for different mass parts of #$l. w, % , g mL+w, % , g mL+4 +,.+ 44 +,++; +,.4 41 +,+!8 +,.; !1 +,+8+8 +,.9 !8 +,+92ry to figure out a simple relationship, which would allow you to find the density for the solution of hydrochloric acid when its mass part is nown.'hat is the density of !.% hydrochloric acid solution)14. 10,11 4 p.Aor the e0ploration of different processes radioacti(e or soCcalled labeled elements often are used.Gsing labeled atoms of radioacti(e chlorine (!1$l), propose the method how one can proof that e6uilibrium between solid Da$l4 and dissol(ed Da$l4 is dynamic, e.g. dissol(ed Da$l4 all the time returns into the precipitate and vice versa.15. 10,11 5 p.Dy addition of 4 (olumes hydrochloric acid (c B ..+ mol-l) to one (olume of mercury (55) acetate (salt of acetic acid) solution (c B .,+ mol-l), electric conducti(ity of obtained solution decreased by factor of se(eral thousands in comparison to the initial solution of hydrochloric acid.#$plain this observation./olubility of compounds in water (g - +..g)7 #g($#!$%%)4 E 5., #g$l4 E ,, acid constant for acetic acid *a B +.,;:+.C5.16. 11 9 p. A6ueous solutions of compounds A, B and C ha(e the same chemical composition, and all the solutions are strongly acidic. 5f they are e(aporated, at the beginning compound A is obtained (it contains 4!.4% /), afterwards E compound B (41.,% /). $ontinuing the heating yields compound C which contains 48.9% /. 5f C is heated at high temperature white crystalline substance D is obtained. A6ueous solution of D is neutral, it colors the gas flame yellow and contains 44.1% /. 5n all the species sulfur e0hibits the same o0idation state.+etermine compounds A& B& C and D. #$plain& why solutions of compounds A& B and C have the same chemical composition. Show what ions are present in this solution. If they are formed during some chemical reaction& write the e%uation for this reaction. Write the e%uations for all the chemical reactions.Show the geometry of the ions that forms species C and D.17. 11 9 p.2o the a6ueous solution of a salt A bromine water was added at 5 o$ temperature till the formation of precipitate B was completed. %btained precipitate was filtered at 5 o$ temperature. $olorless filtrate was heated up to ,. o$ temperature and solution of salt A was added to it till the formation of precipitate B and the impurity C was completed. 3ass of the precipitate B that formed at ,. o$ temperature was 4-! of that formed at 5 o$ temperature. 5f an e0cess of potassium iodide is added to the solution containing +. g of salt A, yellowish precipitate D is formed. D dissol(es in the solution of sodium thiosulfate, but does not dissol(e nor in the ammonia solution, either in diluted nitric acid. *etermine the compounds A, B, C and D, and write the e6uations for all the chemical reactions. 18. 11,12 8 p.3alachite is a basic carbonate of some metal, and its composition is the following7 5.;,%$, !1.+,% %, ..9+% # and 5,.;8% of some unnown metal. 45.. g of malachite was heated and the blac residual was dissol(ed in the hydrochloric acid. 2he obtained salt (inthe solution) was subHected to the complete electrolysis. +!.89 g of metal was obtained.#ow many percents of impurities contain this sample of malachite) 'rite the e6uations for the chemical reactions. 'hat is the amount of electricity that is spend during this electrolysis, if the (oltage was 5.. =) (Aaraday constant , B 915.. $-mol)19. 11,12 6 p./ubstance X is an easily (olatile solid compound and is of great importance in the producing of energy as well as in the military industry. 5t may be obtained in the direct reaction of fluorine with a pure sil(er white metal. 9elati(e density of this compound against the air is +4.+8. 'hat is this compound) And why it is (olatile despite its high molecular weight)*ensity of air is +.49 g-l.20. 11,12 4 p.$alculate the (olume of carbon (5=) o0ide, v (in liters, normal conditions), which is formed by burning m grams of hydrocarbon (or their mi0ture) with mass part of carbon w% in the e0cess of o0ygen.Gsing the obtained e6uation, calculate the (olume of $%4, which would be released by burning of +... g he0adecane $+1#!;. 21. 12 5 p.2o+.. ml of sodium acetate solution + g of white crystalline compound A was added. /olution turned to solid substance and its temperature raised. 2he elemental composition of the obtained substance was the same as that of compound A E it contained +1.9% "a, +,.,% $, 1.1,% # and o0ygen.+etermine compound A. What is the composition of the solution used"-ow one can prepare such a solution"22. 12 13 p. ..91 of an simple compound A was heated at +5. o$ temperature with 4. g of an hea(y colorless li6uid B. After the heating ..;8 g of compound A and appro0imately +8 g li6uidB remained unreacted. @as, e(ol(ed during the heating, was trapped into the !1 g of +.%sodium hydro0ide solution. /olution I was obtained. 2his solution was boiled and ..;8 ofthe pre(iously remained substance A was added to it. /olution II was obtained. 2his solution contains compounds that are widely used in photography. 5f a6ueous solution of barium chloride is added to the solution II, which has been standing in the air for a while,precipitate C is formed. C cannot be completely dissol(ed into the hydrochloric acid.a) 'hat are compounds A, B and C)b) 'hat species are present in the solutions I and II)c) *etermine the mass and composition of precipitate what is formed if li6uid B isadded to the fresh obtained solution II.d) *etermine the (olume of gas, which is e(ol(ed when +. g of li6uid B is added to the fresh solution II.e) 'rite the e6uations for the chemical reactions.23. 12 14 p.3ost widely common drugs against fe(er are aspirine (acetylsalicylic acid) and paracetamol (paraCacetylaminophenol).5dentify and name the (arious functional groups in aspirin and paracetamol.'rite the e6uation for one chemical reaction in(ol(ing aspirin and for one in(ol(ing paracetamol which cold ser(e as uni6ue tests for the discrimination of these two drugs3any antiCfe(er drugs howe(er contain both E aspirine and parecetamol. *escribe how toseparate the mi0ture containing both of these chemicals and obtain both substances in pure forms separately. 'rite the e6uations for these chemical reactions.Aspirin usually is prepared from phenol according to the following scheme78aracetamol could be prepared from phenol as well7'rite the e6uations for all the reactions and name all the organic compounds in(ol(ed in these reactions according to the 5G8A$ nomenclature.24. 12 7 p.+... g organic substance A was dissol(ed !... mL of hot water. %btained solution contained only organic substance B. /olution was cooled and filtered. Ailtered substance B was dried and its mass was +... g. 5n +.. mL (olumetric flas solution from +... g of compound B was prepared. Aor titration of +.... ml of the prepared solution +1.95 ml ..+3 sodium hydro0ide solution are necessary. 5f the obtained compound B is heated, compound A is obtained. *etermine the compounds A and B, write their names according to the 5G8A$ nomenclature, and write the e6uations for all the chemical reactions. 25. 12 5 p./odium hydrosulfide, "a#/, is obtained by bubbling the hydrogen sulfide through the ethanol solution of sodium eto0ide and the formed sodium hydrosulfide is precipitated from the solution by adding of diethyl ether, in which it is not soluble. .alculate the volume of hydrogen sulfide& which is necessary for obtaining 10 g sodium hydrosulfide if the reaction yield is /00..alculate the mass of sodium that is needed to prepare the sodium eto$ide needed for thesynthesis of sodium hydrosulfide.Write the e%uations for all the reactions.26. 12 6 p.%0idation of alyl groups attached to the aromatic rings is of great importance in organic synthesis. Aor instance, nicotic acid ((itamin 88) may be obtained this way from !Cmethylpyridine.!C3ethylpyridine is o0idi&ed with sodium permanganate in wea basic medium (by adding the potassium carbonate to the reaction mi0ture). *uring the reaction, manganese(5=) o0ide is formed from the permanganate. Write the complete e%uation for this reaction.$alculate the mass of potassium permanganate necessary for preparation of +. g nicotic acid if the reaction yield is 8.%.Aor the complete o0idation of !Cmethylpyridine, potassium permanganate is usually taenin e0cess. Defore the e0traction of nicotic acid in this case, unreacted potassium permanganate is remo(ed by adding of potassium sulfite.Write the e%uation for this reaction. 5n terms to e0tract nicotic acid after the reaction is completed, reaction mi0ture is acidified with hydrochloric acid and nicotic acid is precipitated.#$plain& why it is necessary to add hydrochloric acid and write the e%uation for the appropriate reaction.$alculate the (olume of 1.. 3 hydrochloric acid for the complete precipitation of +. g nicotic acid. 5f hydrochloric acid is added in e0cess, nicotic acid dissol(es.Why" Write the e%uation for this reaction.