...Acid-Base Titration: Determination of the Percentages (%) of Sodium Carbonate (Na2Co3) and Sodium Hydroxide (Naoh) in a Mixture Title Acid-base titration: Determination of the percentages (%) of sodium carbonate (Na2CO3) and sodium hydroxide (NaOH) in a mixture Objective To determine the respective weight per cent of sodium carbonate and sodium hydroxide in a mixture by acid-base titration. Result and calculation Part A Titration 1 Titration number 1 2 3 Initial volume of burette( cm3) 5.10 2.70 9.70 Final volume of burette (cm3) 34.40 31.80 39.20 Total volume of HCl used (cm3) 29.30 29.10 29.50 Average volume of HCl required for titration =(29.30+29.10+29.50)/3 cm3 = 29.30 cm3 Titration 2 Titration number 1 2 3 Initial volume of burette( cm3) 4.50 14.00 2.70 Final volume of burette (cm3) 25.00 21.70 22.80 Total volume of HCl used (cm3) 20.50 20.30 20.10 Average volume of HCl required for titration =(20.50+20.30+20.10)/3 cm3 = 20.30 cm3 Part B Titration number Rough 1 2 3 Initial volume of burette( cm3) 4.9 4.80 3.60 2.20 Final volume of burette (cm3) 28.3 28.90 27.70 26.20 Total volume of HCl used until phenolphthalein decolourised (cm3) , x 23.4 24.10 24.10 24.00 Initial volume of burette after adding methyl orange indicator ( cm3) 28.3 28.90 27.70 26.20 Final volume of burette (cm3) 34.1 33.40 32.10 30.70 Total volume of HCl used until phenolphthalein decolourised (cm3) , y 5.8...
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...Title Acid-base titration: Determination of the percentages (%) of sodium carbonate (Na2CO3) and sodium hydroxide (NaOH) in a mixture Objective To determine the respective weight per cent of sodium carbonate and sodium hydroxide in a mixture by acid-base titration. Result and calculation Part A Titration 1 Titration number 1 2 3 Initial volume of burette( cm3) 5.10 2.70 9.70 Final volume of burette (cm3) 34.40 31.80 39.20 Total volume of HCl used (cm3) 29.30 29.10 29.50 Average volume of HCl required for titration =(29.30+29.10+29.50)/3 cm3 = 29.30 cm3 Titration 2 Titration number 1 2 3 Initial volume of burette( cm3) 4.50 14.00 2.70 Final volume of burette (cm3) 25.00 21.70 22.80 Total volume of HCl used (cm3) 20.50 20.30 20.10 Average volume of HCl required for titration =(20.50+20.30+20.10)/3 cm3 = 20.30 cm3 Part B Titration number Rough 1 2 3 Initial volume of burette( cm3) 4.9 4.80 3.60 2.20 Final volume of burette (cm3) 28.3 28.90 27.70 26.20 Total volume of HCl used until phenolphthalein decolourised (cm3) , x 23.4 24.10 24.10 24.00 Initial volume of burette after adding methyl orange indicator ( cm3) 28.3 28.90 27.70 26.20 Final volume of burette (cm3) 34.1 33.40 32.10 30.70 Total volume of HCl used until phenolphthalein decolourised (cm3) , y 5.8 4.50 4.40 4.50 Average volume of HCl required to react with Na2CO3 (2y) =2(4.50+4.40+4.50)/3 cm3 = 2(4.4667) cm3 ...
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... AA Acids, Bases & Indicators Comprehensive tutorial notes Julius G.Thungu jgthungu@gmail.com 0711 354 885 INTRODUCTION TO ACIDS, BASES AND INDICATORS 1.In a school laboratory: (i)An acid may be defined as a substance that turn litmus red. (ii)A base may be defined as a substance that turn litmus blue. Litmus is a lichen found mainly in West Africa. It changes its colour depending on whether the solution it is in, is basic/alkaline or acidic. It is thus able to identify/show whether another substance is an acid, base or neutral. (iii)An indicator is a substance that shows whether another substance is a base/alkaline,acid or neutral. 2.Common naturally occurring acids include: Name of acid | Occurrence | 1.Citric acid | Found in ripe citrus fruits like passion fruit/oranges/lemon | 2.Tartaric acid | Found in grapes/baking powder/health salts | 3.Lactic acid | Found in sour milk | 4.Ethanoic acid | Found in vinegar | 5.Methanoic acid | Present in ants, bees stings | 6.Carbonic acid | Used in preservation of fizzy drinks like coke, Lemonade, Fanta | 7.Butanoic acid | Present in cheese | 8.Tannic acid | Present in tea | 3.Most commonly used acids found in a school laboratory are not naturally occurring. They are manufactured. They are called mineral acids. Common mineral acids include: Name of mineral acid | Common use | Hydrochloric acid (HCl)...
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...Chemistry Acids and Bases I. Acids A. Definition Covalent molecular compound Ionizes in water Forms H+(aq) as the only cation B. Common acids Dil./ conc. HCl Very dil. HNO3 Dil. H2SO4 C. Basicity Number of H+(aq) produced per acid molecule Monobasic HCl, HNO3, CH3COOH Dibasic H2SO4, H2SO3 Tribasic H3PO4 Stepwise ionization for polybasic acids H2SO4 (aq) H+(aq) + HSO4-(aq) HSO4-(aq) H+(aq) + SO42-(aq) D. Physical properties Exist in all three states in pure form Solid (citric acid) Liquid (sulphuric acid H2SO4, carbonic acid H2CO3) Gas (hydrogen chloride HCl) Electrical conductivity Electrical conductor Electrolytes Conduct electricity in aqueous/ molten states Chemically decomposed upon conduction of electricity Mobile ions present: H+(aq) and other anions Conductivity of dibasic acid > monobasic acid More H+(aq) produced by dibasic acid of the same molarity Action on damp blue litmus paper Bluered Action on universal indicator/ damp pH paper Greenred/ turns red 1 © 2013 Victor Fong Chemistry Acids and Bases E. Chemical properties Species responsible for acidic properties: H+(aq) Reaction with metals Acid + metal salt + hydrogen Mg + 2HCl MgCl2 + H2 Only reacts with metals above Cu in MRS/ ECS Observations Metal dissolves to form a colourless/ coloured solution Colourless...
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...29 EXPERIMENT 3. ACID-BASE TITRATIONS: DETERMINATION OF CARBONATE BY TITRATION WITH HYDROCHLORIC ACID BACKGROUND Carbonate Equilibria In this experiment a solution of hydrochloric acid is prepared, standardized against pure sodium carbonate, and used to determine the percentage of carbonate in a sample. An aqueous solution of hydrochloric acid is almost completely dissociated into hydrated protons and chloride ions. Therefore, in a titration with hydrochloric acid the active titrant species is the hydrated proton. This species is often written H3O+, although the actual form in solution is more correctly (H2O)nH+. For convenience we designate it simply H+. Carbonate in aqueous solution acts as a base; that is, it is able to accept a proton to form bicarbonate ion. 2CO3 + H+ HCO3 (1) Bicarbonate is able to combine with another proton to form carbonic acid: HCO3 + H+ H2CO3 (2) Equilibrium expressions for the dissociation of bicarbonate and carbonic acid may be written 2[H+] [CO3 ] K2 = (3) [HCO3] [H+] [HCO3] [H2CO3] and K1 = (4) 30 where K1 and K2 are the first and second acid dissociation constants for H2CO3; the experimentally determined values are K1 = 3.5 x 10-7 and K2 = 5 x 10-11. When successive protonation reactions such as (1) and (2) occur, the extent to which the first reaction proceeds before the second begins depends on the difference between the two acid dissociation constants. By combination of Equations (3) and (4) with those for charge and...
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...FAST AND NEUTRALIZE ACIDS EFFECTIVELY. THEY CAN ALSO ACT AS A LAXATIVE. ANTACIDS CONTAINING BOTH INGREDIENTS SHOULD PROVIDE QUICK, LONG-LASTING RELIEF WITH LESS RISK OF DIARRHEA OR CONSTIPATION. HOWEVER, THE LONG-TERM SAFETY OF ANTACIDS CONTAINING ALUMINUM HAS BEEN QUESTIONED. PROLONGED USE MAY WEAKEN BONES BY DEPLETING THE BODY OF PHOSPHORUS AND CALCIUM. Calcium Carbonate CALCIUM CARBONATE, OR CHALK, HAS BEEN A MAINSTAY OF ANTACIDS FOR A LONG TIME. CALCIUM CARBONATE ACTS FAST AND NEUTRALIZES ACIDS FOR A RELATIVELY LONG TIME. ALSO, IT IS AN INEXPENSIVE SOURCE OF CALCIUM; AMOUNTS RANGE FROM 500 TO 1000 MILLIGRAMS PER TABLET OR DOSE. HOWEVER, PEOPLE CAN OVERDOSE ON CALCIUM. THE MAXIMUM DAILY AMOUNT SHOULD NOT EXCEED 2000 MILLIGRAMS UNLESS A DOCTOR HAS DIRECTED OTHERWISE. Sodium Bicarbonate ONE OF THE LEAST EXPENSIVE AND MOST READILY AVAILABLE ANTACIDS IS NO FARTHER AWAY THAN THE KITCHEN CABINET. SODIUM BICARBONATE, OR BAKING SODA, NEUTRALIZES ACID QUICKLY. THE BAKING SODA BURP IS A SIGN THAT THIS ANTACID IS WORKING; THE BURP IS CAUSED BY RELEASE OF CARBON DIOXIDE GAS, WHICH OCCURS WHEN THE ANTACID NEUTRALIZES THE ACID. Although sodium bicarbonate may provide a short-term solution to indigestion, too much bicarbonate can wreak havoc with the body's acid-base balance and lead to metabolic alkalosis. The high sodium content may also cause problems for people with heart failure or high blood pressure. Forms of Antacid—Alumina, Calcium Carbonate, and Sodium Bicarbonate;...
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...studyguide.pk Acids, Bases and Salts THE THEORY of ACIDS and ALKALIS and a few technical terms: o Acids are substances that form hydrogen ions (H+(aq)) when dissolved in water eg hydrochloric acid HCl gives H+(aq) and Cl-(aq) ions, sulphuric acid H2SO4 gives 2H+(aq) and SO42- ions and nitric acid HNO3 gives H+(aq) and NO3-(aq) ions. o Alkalis are substances that form hydroxide ions (OH-(aq)) in water eg sodium hydroxide NaOH gives Na+(aq) and OH-(aq) ions, calcium hydroxide Ca(OH)2 gives Ca2+(aq) and 2OH-(aq) ions. Note: an alkali is a base soluble in water. o In water, there are trace quantities of H+ and OH- ions BUT they are of equal concentration and so water is neutral. o In acid solutions there are more H+ ions than OH- ions. o In alkaline solution there are more OH- ions than H+ ions. o Acids dissociate to different extents in aqueous solution. Acids that dissociate to a large extent are strong electrolytes and strong acids. In contrast, acids that dissociate only to a small extent are weak acids and weak electrolytes In a similar manner, bases can be strong or weak depending on the extent to which they dissociate and produce OH– ions in solution. Most metal hydroxides are strong electrolytes and strong bases. Ammonia, NH3, is a weak electrolyte and weak base. o BASES eg oxides and hydroxides are substances that react and neutralise acids to form salts and water. Bases which are soluble in water are called alkalis. Acids Some common acids are listed below:...
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...amide BrO2CO3 carbonate HCO32SO4 sulfate HSO42SO3Chemistry I sulfite HSO32C2OPolyatomic Ions oxalate HC2O44 3PO4 phosphate HPO423acids: PO3Here’s a list of common polyatomic ions andH2PO4phosphite 2Name S2OIon + thiosulfate HS3 NH Ammonium* AsO43- 4 arsenate BO33NO3 Nitrate 2SeONO selenate B4O724 Nitrite 2 2SiOOHsilicate SiF623 Hydroxide* 2C4HCN-6 tartrate 4O Cyanide Name perchlorate chlorate chlorite hypochlorite periodate iodate hypoiodite bromate hypobromite hydrogen carbonate (bicarbonate) hydrogen sulfate (bisulfate) hydrogen sulfite (bisulfite) hydrogen oxalate (bioxalate) hydrogen phosphate dihydrogen phosphate Acid Formula Acid hydrogen sulfide Name borate HNO3 Nitric Acid tetraborate HNO2 Nitrous Acid hexafluorosilicate (not really an acid) HOH Water HCN Hydrocyanic Acid SCNThiocyanate HSCN Thiocyanic Acid C2HClO2-acetate (an write ) Perchlorate* alternate way to HClO4 acetate is CH3COOPerchloric Acid 3O 4 ClO3 Chlorate* HClO3 Chloric Acid ClO2 Chlorite* HClO2 Chlorous Acid There are only two positive polyatomic ions: ClOHypochlorite* HClO Hypochlorous Acid + H O2 C2is3calledI the ammonium ion and Acetate HC2 H3 O2 Acetic Acid NH4Chemistry MnO4 Permanganate HMnO4 Permanganic Acid 2+ Hg2 Polyatomic Ions mercury(I) ion is called the SO4 2Sulfate* H2 SO4 Sulfuric Acid 2Sulfite* Sulfurous Acid ! acids:Ion SO3 - a list of common polyatomic ions and acids: H2 SO3 tomic ions and Here’s Tests HSOFormula Hydrogen sulfate or H2 SOFormula Sulfuric Acid 4 Acid 4 Acid Name Ion Name...
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...Aim To prepare a standard solution of sodium carbonate and to standardize a solution of sodium hydrochloric acid using sodium bicarbonate solution Apparatus : 250ml volumetric flask, weighing bottle, burette, pipette, and conical flask Chemicals : Sodium carbonate and hydrochloric acid Procedure A.Preparation of standard solution of sodium carbonate 1. A dry , clean empty weighing bottle is weighed using an analytical balance and the weight is recorded 2. A small quantity , 1.325g of dry sodium carbonate is weighed accurately in a weighing bottle and the weight is recorded . 3. Sodium carbonate is transferred into a 25oml volumetric flask by washing down through a filter funnel with distilled water from the wash bottle . 4. The weighing bottle and filter funnel is rinsed with distilled water and the washed liquid is allowed to flow into volumetric flask to not more than 2/3 full . 5.The volumetric flask is closed with stopper and is shaked moderately until all the sodium carbonate solids dissolves . 6 .The stopper is removed . Distilled water is added slowly and carefully , little by little with dropper , until the level of solution reaches its graduation mark of the volumetric flask . 7. The stopper is replaced and the volumetric flask is inverted and shaked several times to obtain a homogenous standard sodium carbonate solution . B. Standardization of hydrochloric acid solution with the previously prepared standard solution sodium chloride ...
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...of acetic acid in vinegar. Vinegar is a solution of acetic acid, an organic acid of formula CH3COOH (MW = 60.0526 g/mole). In order to be sold as vinegar, it needs to meet the FDA’s guideline of 5.00% acetic acid by mass. Knowing that the density of vinegar is 1.04 g/mL and analyzing this solution by titration, chemists can determine the mass percentage of acetic acid in a sample of vinegar. The titration reaction is given below: CH3COOH + NaOH ( CH3COONa + H2O Reaction 1 A customer has purchased a vinegar solution at a local thrift store at a 20% discount and he believes that the sample of vinegar he has purchased does not meet FDA regulations. He is suing the thrift store for the $0.36 he feels that he has been cheated out of. The court has asked you to analyze the sample and render your verdict. Does this sample conform to the FDA guideline? If 2.00 mL of the thrift store vinegar required 9.73 mL of 0.150 M NaOH to reach the endpoint, then 0.00877 g of acetic acid was present. 9.73 mL NaOH x 1 liter NaOH x 0.150 mole NaOH x 1 mole CH3COOH x 60.0526 g CH3COOH 1000 mL 1 liter 1 moles NaOH 1 mole CH3COOH = 0.0876 grams CH3COOH in sample 2.00 mL vinegar x 1.04 g vinegar = 2.08 g vinegar 1 mL 0.0876 g CH3COOH x 100 = 4.21 % CH3COOH by mass 2.08 g vinegar sample You can find the molarity of acetic acid in vinegar by dividing the number of moles of acetic acid in vinegar...
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...the density. 2. An experiment that you can determine what large supply of unlabeled indicator paper is to put drops of different solutions on the paper and observe if a chemical reaction takes place. By taking a stirring rod and placing a drop of hydrochloric acid on to each paper and record if a color change takes place. The repeat is the process with water and sodium hydroxide solution. Depending if the paper has no change at all or if it turns pink or blue will let you know if an acid, base, or neutral solution was placed on the paper. 3. A simple experiment would allow you to determine which bottle contains what solution is placing a few drops of each on litmus paper. The hydrochloric acid will turn the blue paper red because it is an acidic solution. The sodium chloride solution will not show any change on the paper because it is a neutral solution. Finally, the sodium hydroxide will turn the red litmus paper blue because it is a basic solution. 4. An experiment that would allow me to determine which bottles contains solid sodium chloride or solid sodium carbonate would be to add hydrochloric acid to each and observe the reactions to see if carbon dioxide would form. The sodium carbonate would bubble. 5. The chemical reaction for heating of malachite is Cu(OH)2 CO3 + heat= CuO+H2O. The...
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...name and civics group on all the work you hand in. Write in dark blue or black pen on both sides of the paper. You may use a soft pencil for any diagrams, graphs or rough working. Do not use staples, paper clips, highlighters, glue or correction fluid. Answer any four questions. A Data Booklet is provided. You are reminded of the need for good English and clear presentation in your answers. The number of marks is given in brackets [ ] at the end of each question or part question. At the end of the examination, fasten all your work securely together. 2 This question paper consists of 10 printed pages. SAJC 2010 P3 – Answer any four questions. 1 (a) Hydrolysis of a lipid (containing multiple ester linkages) produced the following fatty acids. Structure I Structure II CH3(CH2)4CH=CHCH2CH=CH(CH2)7COOH CH3CH2CH=CHCH2CH=CHCH2CH=CH(CH2)7COOH (i) In an experiment, hot acidified potassium manganate(VII) was used to oxidise Structure I. Write the structural formulae of all organic products formed during the oxidation. (ii) What is meant by the term cis-trans isomerism? How many cis-trans isomers are present in Structure I? Draw any 2 possible cis-trans isomers. (iii) State the physical state of this lipid at room temperature. Explain your answer. [9] (b) Suggest a possible identity for each of the organic compounds A-E below. Explain your reasoning and write balanced equations for the reactions involved where possible. (i) A, C11H14O2 is a neutral compound. Hydrolysis of A...
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...sulfuric acid) (Sulfuric dioxide is also produce in large quantities in volcanic eruption) • CONTROL implementing national fuel quality standards; • supporting the implementation of tighter vehicle emission standards; and • Promoting alternative fuels. Effects of sulfuric dioxide - These gases irritates the eyes and Couse breathings difficulties by irritating the lungs - [pic] cause inflammation and the phlegm - High level ofCO2, NO and NO2 also leads to inflammation of the lungs called bronchitis Acid Rain It is form when acid air pollutant such as sulfur dioxide and nitrogen dioxide dissolve in rainwater (Nitrogen and sulfur dioxide are acidic . then it dissolve to the rainwater and the water become acidic Effect of acid rain - Acid rain reacts with metals with carbonates with marbles and lime stone. - When this happen metal bridge and stone buildings are damage. - CONTOL Additionally, individuals and society as a whole can participate in various efforts to help reduce acid deposition: - Understand acid deposition’s causes and effects - Clean up smokestacks and exhaust pipes - Use alternative energy sources - Restore a damaged environment - Look to the future - Take action as individuals - (Stone are actually carbonates so , carbonates + acid and metal + acid = damage) - Other effects is acid rain produce...
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...solution containing Sodium Hydroxide, Sodium Carbonate, and Sodium Hydrogen Carbonate Two of these three components can exist in an appreciable amount in any solution because reaction with acids (neutralisation titration) will eliminate the third. The analysis of such mixtures can be realised at any technique: 1) direct titration (Warder’s method) or 2) back-titration (Winkler’s method). The analysis of such mixtures requires two titrations: one with an alkaline-range indicator, such as phenolphthalein, and the other with an acid-range indicator, such as methylorange. 1. Direct titration the mixture of Sodium Hydroxide and Sodium Carbonate The composition of the solution can be deduced from the relative volumes of acid needed to titrate equal volumes of the sample. Titration with hydrochloric acid to a phenolphthalein end point (Vphth): NaOH + HCl = NaCl + H2O Na2CO3 + HCl = NaHCO3 + NaCl Titration with hydrochloric acid to a methyl orange end point (Vmo): NaHCO3 + HCl = NaCl + H2O + CO2 Components in sample Relationship between Vphth and Vmo in the titration of an equal volume of sample NaOH Vphth = Vmo Na2CO3 Vphth = 1/2Vmo NaOH + Na2CO3 Vphth > 1/2Vmo 1. Load a burette with 0,1 N hydrochloric acid solution. 2. To conical flask pour in 10 ml aliquot of sample (VS). 3. Introduce 2-3 drops of phenolphthalein solution, and titrate with 0.1 N hydrochloric acid solution until the solution lost the red...
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...solution and standardization of hydrochloric acid To prepare a standard solution of sodium carbonate and use it to standardize a given solution of dilute hydrochloric acid. Anhydrous sodium carbonate is a suitable chemical for preparing a standard solution (as a primary standard). The molarity of the given hydrochloric acid can be found by titrating it against the standard sodium carbonate solution prepared. The equation for the complete neutralization of sodium carbonate with dilute hydrochloric acid is Na2CO3(aq) + 2HCl(aq) → 2NaCl(aq) + CO2(g) + H2O(l) The end-point is marked by using methyl orange as indicator. Introduction : Chemicals : Apparatus : Procedure : solid sodium carbonate, 0.1 M hydrochloric acid 1. 2. 3. 4. 5. 6. 7. 8. Weight out about 1.3 g of anhydrous sodium carbonate accurately using the method of “weighing by difference”. Transfer the weighed carbonate to a beaker and add about 100 cm3 of distilled water to dissolve it completely. After dissolving, transfer the solution to a 250.00 cm3 volumetric flask. Rinse the beaker thoroughly and transfer all the washes into the volumetric flask. Remember not to overshoot the graduation mark of the flask. Make up the solution to the mark on the neck by adding water. Pipette 25.00 cm3 of sodium carbonate solution to a clean conical flask. Add 2 drops of methyl orange indicator to the carbonate solution. Titrate the carbonate solution with the given dilute hydrochloric acid until the colour of solution just changes...
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