1. 9 5 p.5.0 g of calcium carbonate (containing 3.0 % of alloy) were heated. The obtained gas wasabsorbed by previously weighted sodium hydroxide.1. What was the increase of mass if 98% of the gas were absorbed by the sodium hydroxide?2. Write down equations of proper reactions!. What wi"" be mass of the ca"cium carbonate after heating?#. $ame a compound besides gas emerged whi"e heating ca"cium carbonate. What wi"" be the fraction of mass of it in the remains?2. 9 % p. Acetic acid and citric acid are comonly used compounds. Their formulae are as follows:Acetic acid is a weak one-valent acid while citric acid is a weak three-valent acid.1. &ic"e residua"s in the formu"ae of the acids. oth acetic and citric acids are appropriate means for removal of incrustation from dishes. !0.0 g of incrustation containing "0.0% calcium carbonate# !$.0% magnesium carbonate and !.00% ferrum(%%%) oxide was formed in some vessel.2. &a"cu"ate the 'o"ume of %(% acetic acid )density * 1.(% g+m", needed to c"ean the 'esse". Write down equations for appropriate equations. !. &a"cu"ate mass of citric acid monohydrate &-.8/%0.2/ needed to c"ean the 'esse". Write down equations for appropriate equations. #. 1xp"ain which acid is more comfortab"e to use. !. 9 % p.If the USA decides to attack Iraq one of the possible ways of retaliation of Iracis is burnin the oilfields as it was in the first !ersian "ulf #ar.What wo"ume of &/2 and &/ and how many tonns of water and grim wou"d emergeif 2raq wi"" burn down 34ust3 (5- 6m! )cubic 6i"ometers, of oi" with density of %5( 6g+m!? The elemental composition of oil is as follows& "'% ( and !3% ). *n average "0% of carbon will form (*+# '% , (* and !3% , grim.#. 9 11 p.+00ml of limewater was neccessary for a practical tas-. Technician decided to ma-e it using calcium oxide. ottle containing calcium oxide was not firmly closed. .nd was covered by a thic- layer of dust formed during years. The technician decided not to use this substance. )e weighted +.0g of calcium and put it in a mensure containing +00ml of water.1. Write down equations of reactions for prepearing "imewater from ca"cium oxide. 2. Why the technician decided not to use ca"cium oxide? !. Write down equations of reactions for process emerged in the mensure and ca"cu"ate mass for a"" compounds emerged. #. 2s it possib"e to use the content of the mensure for the practica" tas6? 7ase your answer on ca"cu"ations noting that at 2(& (.1-g of ca"cium hidroxide can be so"'ed in 1((g of water. 5. 8id the technician use the reagents economica""y? 1xp"ain your answer. -. What wou"d you do in his position? %. What is fraction of mass in a saturated "imewater at 2(&? 8. What are storage procedures for the obtained so"ution? 9. 2n what pro'a" reactions "imewater is used? 5. 9*1( % p.The art of fireworks was formed in the $ast while in the $urope the black powder was created which is the main compound for the pyrotechnics materials. The %ranciscan monk &oer 'eakon was e(plorin properities of saltpetre )*+,-. and discovered a way to create the black powder. The composition of it remains practically unchaned since /010: 234 of Indian saltpetre )*+,-.5 /64 of sulfur5 and /34 - carbon.%n explosion of the blac- powder potassium sulfide# the main compound of the air and carbon dioxide are formed.1. Write down equations for reaction corresponding to exp"osion of the b"ac6 powder. 2. 9or creating of !( grams of the b"ac6 powder a charcoa" containing 2(% of non*f"ammab"e a""oy was used. :he presence of a""oy was ta6en into account whi"e ma6ing the powder. &a"cu"ate the mass and fraction of mass of carbon in the fresh"y made poeder. !. 5( grams of the b"ac6 powder were made by using on"y pure reagents. Wi"" there be enough oxygen to burn a"" the carbon according to the equation of reaction? #. Wi"" a"" the su"fur be con'erted into potassium su"fide? 7ase your answers onca"cu"ations -. 1( # p.The comb present in the mucous membrane of a human stomach secrete 76.84 muriatic acid. The acidous medium is essential for successful action of en9ymes splittin nutritives. The optimum p: in the stomach is -0. 1. &a"cu"ate the optimum concentration of muriatic acid in the stomach. /nlarged concentration of acid causes burning and may cause serial affections of stomach. To decrease concentration of acid one may use some medical preperates containing bases. .n example of such preperates is &ennie. *ne pastille of &ennievontains 0"0 mg of calcium carbonate and "0 mg magnesium carbonate2. &a"cu"ate the "ess number of pasti""es needed to e"e'ate p. from 1 to 25 assuming stomach to contain (.! " of "iquid. %. 1( - p.1ome unidentified crystalline substance ; was explored. To identify this substance one needed to determine its molar weight. 2hysical methods of exploration were used to determine the crystalline structure of the substance. %t proved to be a ionic type criystal grid. The element forming crystal grid is cube with length of edge 3.!34!0," cm and the cube is formed by only one formular unit of substance ; (it5s li-e the cation is inside the cube and each pea- of cube is formed by !6" of the anion). 7ater was discovered the density to be 3.$' g6cm3.&a"cu"ate mo"ar weight of substnce ; and determine iniet 'ie"as; mo"masu un nosa6iet5 6as t? ir par 'ie"u5 4a t?s formu"'ien@bu 'eido 2< grupas met?"s un 6?ds ha"og=ns. 8. 1( % p.The solution contained a soluble compound of a two valent metal 8e# mass of the metal5sions in the solution was !.00g.1ulfate of the metal is practically insoluble. 1ulfuric acid (concentration c 9 0.! mol6l) was gradually added to the solution. /xperiment was ended when !00 ml of the solution of sulfuric acid were added.1. &a"cu"ate mass of the precipitation after experiment if Ae B Cr D 7a. 2. &onstruct a mathematica" equation showing the mass of precipitation m depending on the 'o"ume of su"furic acid v added during the experiment. !. Eepresent obtained equation graphica""y if Ae B Cr D 7a. 9. 1(*11 - p.. plastic bottle in the lab contained an unidentified li:uid. The li:uid consistet of two layers which didn5t mix together. They were seperated to identify.*ne of the layers turned out to be an organic compound with molar wieght !!$.5 g6mol. %t consisted of 0.00" fractions by mass )# 0."$! , (l and one other element.1, 8etermine chemica" composition of the organic substance.The second layer was a water solution of two compounds coloring paper of universal indicator red.2, What substances may cause co"oring paper of uni'ersa" indicator red?o ases o .cids o 1alines o 8ixture of acid and saline !0 ml of the solution was titrated with 0.05 8 ;a*). 3 ml of ;a*) were used for titration. .fterwards there was only one substance in the solution constitued of two elements in proportions !&! and the relation between molar wights of the elements is 0.03".!, 8etermine which two substances were present in the initia" samp"e.The titrated sample was steamed and the dry remains weighted. 8ass was 0.!+"' g.#, 8etermine amount of both substances in the initia" samp"e.5, $ote the correct answerFo 7ayer of water solution in the bottle was above the organic substance o 7ayer of water solution in the bottle was below the organic substance 62 of thermal energy was released.&a"cu"ate composition of the mixture in mo"ar parts assuming that burning one mo"e of butane 28%% 6G are re"eased and one mo"e of propane * 1195 6G.?9"#3!3 -2a@l@mol,!@A,!0o ( 9 +'3#!5 A 12. 11 - p.< and 7 are elementar substances and in normal conditions are gases. They react with an explosion even at B+50 o( and form a substance & which is a wea- acid in a water solution. oiling point of the substance is at !$#5 o( and in this temperature steam densityratio versus hydrogen is 00. ?aising the temperature this ratio decreases and reaches minimum above $0 o(.1. What are gases < and 7? 2. 8etermine substance & assuming that transmitting it through so"ution of ca"cium hydrogencarbonate a white precipitation is formed and some gas ooHes. !. 1xp"ain why the density ratio of & 'ersus hydrogenium decreases whi"e increasing temperature? 1!. 11*12 11 p.,ne of the oldest known metals is copper.,ur ancestry copper and its alloys used to make bi;outerie5 housecraft requisites and weapons. Today copper is widely used in technique.1. What for is used copper of 'ery high purity )99595%,? Why especia""ycopper? ,res usually contains less than 34 of copper. To determine e(act fraction of mass of copper in a sample of ore containin copper o(ides a chemical analysis is made. concentration of copper ions usually is done fotometrically e(plorin absorption of liht in solutions. Absorption A is proportional to its concentration in solution:A = b c, where < = molar absorption of the substance )if c> / mol?l.5 b = path of the liht ray5 cm5 c = concentration of the substance5 mol?l.. sample with mass !.000g was treated with excess of sulfuric acid. (olour of copper hydrate ion is not intensive enough Therefor excess of sulfuric acid was neutrali=ed with ;a*) and some ammonia was added and the solution was diluted to 500 ml with water. . dar- blue solution was obtained.2, Write equations of the chemica" reactions noted abo'e!, What are comp"ex compounds5 how do they form?.bsorption of the solution was investigated in a layer of ! cm and obtained . 9 0.!50. 8olar absorption of copper tetraaminocomplex is !+0 l 6 (mol.cm)#, &a"cu"ate fraction of mass for copper in the samp"e +owdays copper usually is obtained in a hydrometalurical process where ore containincopper o(ide is e(tracted by sulfuric acid and then copper is obtained from the solution by electrolysis.5, Write equation for e"ectro"ysis of copper su"fate &a"cu"ate time to obtain 1.((6g of copper in an e"ectro"ysis p"ant if current is 15(( < and outcome by current is 9(%.Chile exploring copper compounds a young chemist decided to obtain copper (%%) hydroxide. To be sure he added a lot of concentrated ;a*) to a solution of copper sulfate. %n the beginning really a blue precipitation formed but they dissolved when more solution was added.Then he decided to obtain copper (%%) iodide mixing copper(%%) sulfate with excess of potassium iodide. .nd again something failed instead of a nice blue colour a brown precipitation formed which turned violet when gasoline was added. -, .e"p your co""egue Write equations for described reactions and exp"ain why the youbg chemist fai"ed to obtain wanted substances? 1#. 12 5 p.To describe fraction of unsaturated organic substances in some samples li-e fat and oil the so called iodine number is used which shows mass of iodine in grams which will reactwith !00 g of substance saturating the unsaturated bounds. 1ample of fat substances consists of glycerin tripalmitate and glycerin trioletate. &a"cu"ate amount of g"ycerin trio"etate in the samp"e in mo"% if the iodine number for the samp"e is G B -.!5.2almitic acid , (!0)3+*+# oleic acid , (!")33*+. 15. 12 1% p.@ust 36 years ao soda was widely used for washin now its completely replaced by washin powder. It always contains one or more surface - active substances whose molecule contains a lon hydrofobe residual of hydrocarbon and a hydrofile roup usually formin ions. Aost of powders also contains en9ymes5 water mitiaters and somestron o(idiser. for e(ample a washin powder miht contain the followin substances: peptidase5 sodium salt of some alkylben9enesulfonic acid5 sodium perborate and sodium triphosphate.1. What is the medium in soda so"ution? Aoti'ate your answer with equation ofproto"ysis )hydro"ysis, reaction. What mystica" changes occours to fat in a water so"ution of soda whi"e heating? What is the name for such reactions. Write what happens to such mo"ecu"e of fatF$ame a"" substances formed in the reaction. 2. :o wich of named substance c"asses be"ongs each substance constituing washing powder? !. .idrofobe groupe of surface acti'e substance during the washing is inc"uded inside the fat paric"es whi"e the hydrofi"e remains in the water. Chow how the surface acti'e substance p"aces on the surface of fat and enab"es its remo'a" from contexture. #. What c"ass of substances is sp"it by enHyme contained by washing powder? What is name for chemica" bound sp"it by enHyme? What c"ass of substances be"ongs enHyme itse"f? Write an examp"e for enHyme cata"ysed reaction. &hoose any simp"e bui"t compound which may be sp"it by enHyme as substrate. What is optimum temperature for anHymatic reactions? .ow boi"ing affects structure and action of enHyme?5. Water mitigater inc"uded in the washing powder forms so"ub"e comp"ex compounds with ions of ca"cium and magnesium. Chow structure for anion. 2n a hard water fatty acids forms inso"ub"e sa"ines of ca"cium and magnesiumwhic precipiates on surface of contexture. Write an examp"e for such reaction)note the medium present in the so"ution,.-. 8etermine degree of oxidation for each atom in the oxidiser added to washingpowder. :he oxidiser s"ow"y hydro"yses in water so"ution forming hydrogen peroxide and one 'a"ent anion where the centra" atom is bound to fourequa" groups. Write equation for this reaction )none of atoms changes degree of oxidation in this reaction,. Write equations for ha"f*reaction of reduction of hydrogen peroxide during washing. 2n what temperature and medium hydrogen peroxidewou"d be the most effecti'e as oxidiser?9or what 6ind of smutchs to c"ean oxidiser is added to powder? 1-. 12 1# p.The sweet taste of honey is caused by fructose )fraction of mass in honey - 164.5 lycose )-64.5 maltose )24. etc.Aaltose is a disacharide which is formed when from two molecules of -B-lycose one molecule of water splits off.1. &a"cu"ate 'o"ume of carbon dioxide needed by p"ants in photosynthesis so that bees may co""ect 1 6g of honey )in warm and sunny summer days when temperature is 25 o& and pressure %8( mm .g,. Write equation for photosynthesis. 2. In a human body honey is CburntC to obtain enery. .Write equations for appropriate equations &a"cu"ate 'o"ume of air needed to inha"e for 3burning3 of 1(( g of honey )in co"d and rainy autumn day when temperature is 1( o& and pressure * on"y %#( mm .g,. ;ote that oxygen volume part in the air is !0%.:uman inhales and e(hales on averae /1 times per minute each time inhalin 7 6.3 l of air. &a"cu"ate how "ong a human ha' to breathe to 3burn3 1(( g of honey.(ombustion heat for glycose is +"!0 ->6mol# fructose B +"+' ->6mol and maltose B 503$ ->6mol. &a"cu"ate how many "iters of water might be heated from a room temperature )2( o&, to temperature of human body )!-55 o&, with energy obtained by eating 1(( g of honey specific heat for water is #518 G+)g0I,.!. Glycose and fructose in honey is mainly formed from disacharide as a result of action bee's enzymes and acids Molecule of sacharose is formed by residuals of -D-glycose and -D-fructose and it is an unreducing carbohydrate. Write formu"a of sacharose and exp"ain why it is an unreducing carbohydrate. Write equation for reaction where *8*g"ycose and *8*fructose are formed from saccharose.!litting of saccharose is catalysed by enzyme invertase. "ts molar #ieght is $%&'Da ($%& &&& g)mol*. +n the bottle is said that , mg of invertase coincides to -&& units of activity. .nzyme #ith activity one unit s!lits , mmol of saccharose !er minute (-- o/, !0 1,-*. &a"cu"ate number of saccharose mo"ecu"es sp"it byone mo"ecu"e of in'ertase in one second.#. Aa"tose is a reducing carbohydrate. 8raw structura" formu"a for ma"tose.