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Analytical chemistry Analytical chemistry is the area of chemistry responsible for characterizing the composition of matter, both qualitatively (what.

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1 Analytical chemistry Analytical chemistry is the area of chemistry responsible for characterizing the composition of matter, both qualitatively (what is present) and quantitatively (how much is present). Analytical chemistry is the study of the separation, identification, and quantification of the chemical components of natural and artificial materials. Analytical chemistry is also focused on improvements in experimental design, chemometrics, and the creation of new measurement tools to provide better chemical information. Analytical chemistry has applications in forensics, bioanalysis, clinical analysis, environmental analysis, and materials analysis.

2 characterization analysis
An analysis in which we evaluate a sample’s chemical or physical properties. qualitative analysis An analysis in which we determine the identity of the constituent species in a sample. quantitative analysis An analysis in which we determine how much of a constituent species is present in a sample. fundamental analysis An analysis whose purpose is to improve an analytical method’s capabilities.

3 Quantitative analysis
Chemical Analysis : A process that provides chemical or physical information about the constituents in the sample or the sample itself. Qualitative analysis Quantitative analysis gives an indication of the identity of the chemical species in the sample. determines the amount of one or more of these components what is present? how much is present?

4 Analytical methods can be separated into classical and instrumental
Classical methods (also known as wet chemistry methods) Instrumental methods use only chemicals for separations such as precipitation, extraction and qualitative analysis by color, odor, or melting point. Quantitative analysis is achieved by measurement of weight or volume. Gravimetric analysis Volumetric analysis (Chemical tests ) use an apparatus to measure physical quantities of the analyte such as light absorption, fluorescence, or conductivity. Spectroscopy Electrochemistry Chromatography

5 a sample is a limited quantity of something which is intended to be similar to and represent a larger amount of that thing(s). The components of interest in the sample are called analytes, the remainder of the sample is the matrix. Technique is a chemical or physical principle that can be used to analyze a sample. A method is the application of a technique for the determination of a specific analyte in a specific matrix. A procedure is a set of written directions detailing how to apply a method to a particular sample. Constituent : A component of a sample; it may be further classified as: A major constituent % 1-100 Minor constituent % 0,01-1 Trace constituent ˂ %0,01

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7 Statistical Analysis of the Results
Measurement : An experimental determination of an analyte’s chemical or physical properties. Measurement data give only an estimate of the ‘true’ value. Length : Mass : Time: Temperature:

8 Range = w = Xlargest – Xsmallest
True Result The 'correct' value for a measurement which remains unknown except when a standard sample is being analysed. It can be estimated from the results with varying degrees of precision depending on the experimental method. Mean The mean, X, is the numerical average obtained by dividing the sum of the individual measurements by the number of measurements. (The average value of a set of data -X-). Median The median, Xmed, is the middle value when data are ordered from the smallest to the largest value. Or the value for a set of ordered data, for which half of the data is larger in value and half is smaller in value ( –Xmed). Range (Spread ) The range, w, is the difference between the largest and smallest values in the data set. It is a measure of precision. Range = w = Xlargest – Xsmallest Mean: The arithmetic average of a replicate set of results. Median: The middle value of a replicate set of results. N ∑ xi i= X1 + X2 +X Xn X = = N N Mean

9 xi - xt Er = ----------- . %100 Xt Precision
is the closeness of data to other data that have been obtained in exactly the same way. Sometimes called the variability, it can be represented statistically by the standard deviation or relative standard deviation. Accuracy The closeness of an experimental measurement or result to the true or accepted value. Accuracy is usually expressed in terms of error or absolute error. (Bias) Error The difference between the true result and the measured value.. E = xi - xt Absolute Error defined as the actual difference between the true result and the experimental value in the same units. Relative Error is the absolute error divided by the true value. Uncertainty The range of possible values for a measurement. xi - xt Er = ‰1000 Xt (parts per thousond) xi - xt Er = %100 Xt (percentage relative error)

10 Calculate the mean, median, absolute and relative error for the following data set
Fe concentration 19,4ppm 19,5ppm 19,6ppm 19,8ppm 20,1ppm 20,3ppm

11 Classification of Errors
On the basis of their origin, errors may usually be classified as determinate or indeterminate. Systematic (determinate) Error Are the errors which can be avoided or whose mahnitude can be determined. They are (in principle at least) measurable and for which a correction may be made.          operational and personal error          instrumental and reagent error          errors of methods Sampling Errors Random (indeterminate) Error They are due to causes over which the analyst has no control and which in general are so intangible taht they are incapable of analysis. They do not have a definite measurable value. Gross Error

12 Statical Evulation of the Random (indeterminate) Error
– (x-μ)2/2 σ2 e y = σ (2 П)^ 1/2 x herbir ölçümün değeri μ bir çok ölçümün aritmetik ortalaması x – μ ortalamadan sapma σ standart sapma y her bir x - μ değeri için bulunma frekansı

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14 Relative Standard Deviation (RSD) coefficient of variation
is a measure of the precision of a population of data Variance (σ2 or s2) The square of the standard deviation. The variance is a parameter describing in part either the actual probability distribution of an observed population of numbers, or the theoretical probability distribution of a sample of numbers. Relative Standard Deviation (RSD) coefficient of variation is the percent relative standard deviation Degree of Freedom An independent variable. For N measurements it is equal to N -1

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16 Calculate the standard deviation of the following experimental results
Lead concentration in blood 0,752ppm 0,756ppm 0,751ppm 0,760ppm

17 ∑ (xi – x1 )2 + ∑ (xi – x2 ) Spool = ( )^1/2 N1 + N2 + N – Nt

18 Number of measurements
Calculate the stardard deviation of the method. Sample No Number of measurements Hg concentration ppm 1 3 1,80 1, ,64 2 4 0, ,98 1,02 1,10 3,13 3,35 6 2,06 1, ,12 2,16 1,89 1,95 5 0, , ,64 0,49 2, , ,70 2,48 2,44 7 1, , ,22 1,04

19 What are the standard deviation, the relative standard deviation, and the percent relative standard deviation for the folowing data

20 What are the standard deviation, the relative standard deviation, and the percent relative standard deviation for the following data

21 1,76 (±0,03) + 1,89 (±0,02 ) - 0,59(±0,02) = ? [ 1,76 (±0,03) x 1,89 (±0,02 ) ] / 0,59(±0,02) =?

22 The pH of a solution is defined as
pH = –log[H+] where [H+] is the molar concentration of H+. If the pH of a solution is 3.72 with an absolute uncertainty of ±0.03, what is the [H+] and its absolute uncertainty?

23 The pH of a solution is defined as
pH = –log[H+] where [H+] is the molar concentration of H+. If the pH of a solution is 3.72 with an absolute uncertainty of ±0.03, what is the [H+] and its absolute uncertainty?

24 The Nature and Origin of Errors
On the basis of their origin, errors may usually be classified as determinate or indeterminate. The first are those having a value which is (in principle at least) measurable and for which a correction may be made. The second fluctuate in a random manner and do not have a definite measurable value. Indeterminate errors arise from the unpredictable minor inaccuracies of the individual manipulations in a procedure. A degree of uncertainty is introduced into the result which can be assessed only by statistical tests. The deviations of a number of measurements from the mean of the measurements should show a symmetrical or Gaussian distribution where μ is the mean and s is the standard deviation. The width of the curve is determined by s, which is a useful measure of the spread or precision of a set of results, and is unique for that set of data. An interval of μ ± s will contain 68.3% of the statistical sample, whilst the intervals μ ± 2s and μ ± 3s will contain 95.5% and 99.7% respectively.

25 Confidence Intervals for Populations
Range of results around a mean value that could be explained by random error. there is a 68.26% probability that a member selected at random from a normally distributed population will have a value in the interval of m ± 1s. In general, we can write Xi = m ± zs where the factor z accounts for the desired level of confidence. Values reported in this fashion are called confidence intervals.

26 Confidence intervals also can be reported using the mean for a sample of size n, drawn from a population of known s. The standard deviation for the mean value, s , which also is known as the standard error of the mean

27 What is the 95% confidence interval for the analgesic tablets if an analysis of five tablets yields a mean of 245 mg of aspirin? the population standard deviation for the amount of aspirin in a batch of analgesic tablets is known to be 7 mg of aspirin.

28 What is the 95% confidence interval for the analgesic tablets if an analysis of five tablets yields a mean of 245 mg of aspirin? the population standard deviation for the amount of aspirin in a batch of analgesic tablets is known to be 7 mg of aspirin.

29 Confidence Intervals for Samples
Once the reliability of a replicate set of measurements has been established the mean of the set may be computed as a measure of the true mean. Unless an infinite number of measurements is made this true mean will always remain unknown. However, the t-factor may be used to calculate a confidence interval about the experimental mean, the confidence interval as a way to report the most probable value for a population’s mean, m, when the population’s standard deviation, s, is known. Since s2 is an unbiased estimator of s2, the term z in The confidence interval equation is replaced with the variable t, where t is defined such that t ³ z at all confidence levels. t is a statistical factor derived from the normal error curve s is the estimated standard deviation and N is the number of results.

30 t is a statistical factor derived from the normal error curve
s is the estimated standard deviation and n is the number of results.

31 What is the 95% confidence interval for the folowing data?

32 The accepted value for the chloride content of a standard sample obtained from extensive previous analysis is 54.20%. Five analyses of the same sample are carried out by a new instrumental procedure, 54.01, 54.24, 54.05, 54.27, 54.11% being the results obtained. For the 95% confidence interval, is the new method giving results consistent with the accepted value?

33 The accepted value for the chloride content of a standard sample obtained from extensive previous analysis is 54.20%. Five analyses of the same sample are carried out by a new instrumental procedure, 54.01, 54.24, 54.05, 54.27, 54.11% being the results obtained. For the 95% confidence interval, is the new method giving results consistent with the accepted value?

34 differences between outlier and Nearest value to it
Dixon’s Q-test. Statistical test for deciding if an outlier can be removed from a set of data. The Q-test compares the difference between the suspected outlier and its nearest numerical neighbor to the range of the entire data set. outlier: Data point whose value is much larger or smaller than the remaining data. differences between outlier and Nearest value to it Qexp = Range (spread) Qexp is greater than Q(a, n), then the null hypothesis is rejected and the outlier may be rejected. When Qexp is less than or equal to Q(a, n) the suspected outlier must be retained. Q (% 90 confidence interval) 0,94 0,76 0,64 0,56 0,51 0,47 0,44 0,41 Number of measurements 3 4 5 6 7 8 9 10

35 The following masses, in grams, were recorded in an experiment to determine the average mass of a U.S. penny. Determine if the value of g is an outlier at % 90 confidence level.

36 Comparing Two Sample Means

37 Tables below show results for two separate experiments to determine the mass of a circulating U.S. penny. Determine whether there is a difference in the means of these analyses at a %95 confidence level.

38 Tables below show results for two separate experiments to determine the mass of a circulating U.S. penny. Determine whether there is a difference in the means of these analyses at a %95 confidence level.

39 The %w/w Na2CO3 in soda ash can be determined by an acid–base titration. The results obtained by two analysts are shown here. Determine whether the difference in their mean values is significant at a %95 confidence level

40 Comparing Two Sample Variances
F-test Statistical test for comparing two variances to see if their difference is too large to be explained by indeterminate error. The F-test can be extended to the comparison of variances for two samples If Fexp is greater than Fcri, the analysis is not under statistical control.

41 Tables below show results for two separate experiments to determine the mass of a circulating U.S. penny. Determine whether there is a difference in the precisions of these analyses at %95 confidence level. the variances are s2A = and s2B=

42 A new method for Ni analysis in the stainless stel is being compared with another method, is the new method is acceptable?

43 the results of the analysis of vitamin B are shown below,.
81,10 79, , ,70 Calculate confidence interval for 95% confindence level If the true value 80,00, is there any significant difference between mean values at a %95 confidence level

44 Sistematik Belirli Hata 1- Sabit hatalar : analiz edilen numune miktarından bağımsızdır. 2- Orantılı hatalar : numunenin miktarı ile orantılı olarak azalır veya artar

45 F Testi (standart sapmaların karşılaştırılması)
İki farklı kişinin yaptığı analizlerin veya iki farklı metotla elde edilen sonuçların standart sapmalarının karşılaştırılmasında kullanılır. Farklı sonuçların standart sapmalarının karesi birbirine bölünür ve sonuç tablodaki F değeri ile karşılaştırılır.

46 Aqueous Solution Chemistry
Precipitation Reactions Acids, Bases, and Neutralization Reactions Oxidation–Reduction (Redox) Reactions Complex formation reactions

47 Solutions Solvent solute
Homogeneous mixtures are called solutions. Solvent solute is the component present in greatest amount or determines the state of solution exist is a component present in a lesser quantity and it is said to be dissolved in the solvent. Solvent is the component present in greatest amount or determines the state of solution exist. A solute is a component present in a lesser quantity and it is said to be dissolved in the solvent.

48 Solubility is the maximum amount of solute that dissolves in a given quantity of solvent at a specific temperature to produce a saturated solution saturated solution. The solution in which no more solute can be dissolved is said to be saturated solution. Super saturated solution. is a solution in which has higher amount of solute than saturated solution Unsaturated solution is a solution in which contain less amount of solute than saturated solution

49 nonelectrolyte Substances such as sucrose or ethyl alcohol, which do not produce ions in aqueous solution, are called nonelectrolytes. electrolytes Substances such as NaCl or KBr, which dissolve in water to produce conducting solutions of ions, are called electrolytes. strong electrolytes, weak electrolytes. Compounds that dissociate to a large extent (~100%) into ions when dissolved in water are said to be strong electrolytes, compounds that dissociate to only a small extent are weak electrolytes.

50 Mass of solute Solution Concentrations
Percent by mass = x 100 Mass of solution Volume of solute Percent by volume = x 100 Volume of solution Mass / volume percent = x 100 (gr/100ml)

51 Solution Concentrations
Number of moles of solute Molarity = Number of liters of solution Molality = Number of kilograms of solvent Moles of component i Mole fraction = total moles of all solution components Parts per million (ppm), Parts Per Billion(ppb) mg solute g solute 1 ppm = ppb = kg solution kg solution

52 Mol number m n = MA Molarity n M= mol/L V density d = gr/mL

53 Diluting Concentrated Solutions
Minitial x Vinitial = mol number = Mfinal x Vfinal Minitial x Vinitial = Mfinal x Vfinal Dilution The addition of solvent to solution is called dilution. it does not change the amount of solute in a solution but changes the solution concentration..

54 Find the molarity of a solution that 23
Find the molarity of a solution that 23.4g of Na2SO4 was dissolved in water and diluted to 250.0ml Na2SO4: 142 calculate the molarity of H2SO4 solution when we dilute 50.0 mL of a solution of 2.00 M H2SO4 to a volume of mL. There is a 2000ml of 8M H2SO4 solution in the lab. A student needs 800ml of 2M H2SO4 solution to carry out an experiment. In order to prepare this solution a- how many ml of 8 M H2SO4 solution should the student use? b- how many ml of distilled water should be added? Calulate the molarity of the solution prepared by mixing 400ml of 0.6M HNO3 solution with 200ml water?

55 How can you prepare 500ml 0.10 M H2SO4 solution from 3.0M H2SO4?
Q1 How can you prepare 500ml 0.10 M H2SO4 solution from 3.0M H2SO4? Q2 How would you prepare mL of M NaOH solution starting from a concentration of M? Q3 What is the final concentration if 75.0 mL of a 3.50 M glucose solution is diluted to a volume of mL?

56 question. A solution has a density of 1.235g/ml and contains 90.0% glycerol C3H8O3 and 10% H2O by mass. Determine a- the molarity of C3H8O3 b- the molarity of H2O c- mole fraction of C3H8O3 d- mole percent of H2O e- the molality of H2O

57 Reactions in Aqueous Solution
Precipitation reactions Are the reactions, an insoluble solid is formed, the solid product is called as a precipitate. Ag+(aq) + Cl-(aq) → AgCl(s)

58 Solubility is the maximum amount of solute that dissolves in a given quantity of solvent at a specific temperature to produce a saturated solution saturated solution. The solution in which no more solute can be dissolved is said to be saturated solution. Super saturated solution. is a solution in which has higher amount of solute than saturated solution Unsaturated solution is a solution in which contain less amount of solute than saturated solution

59 Solubility of most of solids increase with temperature.
Solubility of gases decrease with increased temperature Solubility of a gas increases as the gas pressure is increased. Types of solvent and solute is important, like dissolves like, generally nonpolar substances are soluble in nonpolar substances, polar solvents dissolves ionic and polar substances.

60 all nitrates, acetates and perchlorates are soluble
solubility rules Soluble salts salts of 1A groups (Na, K, Li,) and NH4+ are soluble all nitrates, acetates and perchlorates are soluble NO3 (Nitrat), CHCOO- (asetat) ,ClO4 (perklorat) all chlorides (halogens) are soluble except (AgCl, Hg2Cl2, PbCl2) most sulfates (SO42+ ) are soluble except (Sr SO4, Ca SO4 , Ba SO4 , Pb SO4 ) Cl-, Br-, I- SO42- Li+, Na+, K+, Rb+, Cs+ NH4+ NO3- ClO CH3CO2-

61 solubility rules Slightly soluble all OH- hydroxides are insoluble except those of 1A group (Na, K, Li,) and NH4+ all sulfides S2- are insoluble except those of 1A group (Na, K, Li,) and NH4+ all carbonates are insoluble except those of 1A group (Na, K, Li,) and NH4+ All PO43- are insoluble except those of 1A group (Na, K, Li,) and NH4+ CO32-, PO43- OH-, S2-

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63 What will happen if Na2CO3 and CaCl2 solutions are mixed ?
What will happen if CuSO4 and NaNO3 solutions are mixed ?

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65 solubility product constant
Ionic compounds of alkali metals (like NaCl, KBr, LiNO3 ..) generally dissolve completely in water. But many ionic compounds are only slightly soluble in water. We use the term insoluble for such compound. Ksp is the solubility product constant and is equal to the product of the concentration of the ions involved in the equilibrium, each raised to the power of its coefficient in the equilibrium equation. Ksp has a fixed value for a given system at a particular temperature. SrCrO4(s)  SrCrO4(aq) SrCrO4(aq)  Sr2+(aq) + CrO42-(aq) Ksp = [Sr2+] [CrO42-] Solubility equilibrium Ksp Al(OH)3  Al3+ + OH- 1.3x10-33 ZnS  Zn2+ +S2- 1.6x10-24 BaCO3 Ba2+ +CO32- 5.1x10-9 MgCO3 Mg2+ +CO32- 3.5x10-8 PbCl2  Pb2+ + 2Cl- 1.6x10-5 AgCl  Ag+ + Cl- 1.8x10-10

66 question: write the solubility product constants for Ca3(PO4)2, Ag2CrO4, CaF2, PbSO4

67 Solubility and Ksp question: solid barium sulfate is shaken in contact with pure water at 25°C for several days. At the equilibrium saturated barium sulfate solution contains 1.04x10-5M Ba2+, what is the Ksp for BaSO4 question: Ksp for CaF2 is 3.9x10-11, what is the solubility of CaF2 in water in grams per liter. Solubility is the quantity of substance that dissolves in a given quantity of water. It is often expressed as grams of solid per 100g of water. Ksp and solubility are related and one can be calculated from other.

68 Common ion effect The solubility of a slightly soluble ionic compound is lowered when a second soluble that furnishes a common ion is added to solution. question: calculate the molar solubility of Ag2SO4 in 1.0 M Na2SO4. Ksp for Ag2SO4 is 1.4x10-5

69 Ksp and Precipitate formation
Qip is generally called ion product, it is the product of ion concentrations raised to appropriate powers. SrCrO4(aq)  Sr2+(aq) + CrO42-(aq) Qip = [Sr2+] [CrO42-] Qip < Ksp no precipitate occur Qip = Ksp solution just saturated Qip > Ksp precipitation should occur

70 Selective prepicitation or fractional precipitation
One ion is precipitated while the other(s) remains in solution. For this purpose there must be significant differences in their Ksp. question: M AgNO3 is adding slowly to a solution that has [CrO42-] = 0.010M and [Br-]= 0.10M ( Ksp for Ag2CrO4 is 1.4x10-5, Ksp for AgBr is 5.0 x10-13 ) show that AgBr (s) precipitates before than Ag2CrO4(s) at the point where Ag2CrO4 begins to precipitate, what is the [Br-] remaining in solution? is separation of Br- and CrO42- by fractional precipitation feasible?

71 Activity Effects activity
True thermodynamic constants use a species activity in place of its molar concentration (a). activity coefficient The number that when multiplied by a species’ concentration gives that species’ activity (g). ionic strength A quantitative method for reporting the ionic composition of a solution that takes into account the greater effect of more highly charged ions (m).

72 Calculate the ionic strength of 0. 10 M NaCl
Calculate the ionic strength of 0.10 M NaCl. Repeat the calculation for a solution of 0.10 M Na2SO4.

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74 Calculate the solubility of Pb(IO3)2 in a matrix of 0.020 M Mg(NO3)2.

75 Quantitatif Analysis Titrimetry and Gravimetry
Gravimetry: is a method in which the signal is a mass or change in mass to find the amount (or concentration) of analyte in the sample. .

76 2 molecules of H2 1molecules O2
2 H2 (g) O2 (g)  H2O (s) 2 molecules of H molecules O2 two moles of H2 reacts with one mole O2 and two moles H2O is produced. 4 grams of H reacts with g O and g H2O is produced.

77 Reaksiyon Stokiometrisi
2 H2 (g) O2 (g)  H2O (s) 2 molekül H molekül O2 ile reaksiyona girer 2 molekül H2O oluşur 2 mol H mol O2 ile reaksiyona girer ve mol H2O oluşur 4 gram H g O2 ile reaksiyona girer ve g H2O oluşur

78 KBr(aq) + AgNO3 (aq)  AgBr(s) + K+ (aq) + NO3- (aq)
what mass of AgBr is formed when a solution containing 3.45 g of KBr is mixed with a solution containing 7.28 g AgNO3? KBr(aq) + AgNO3 (aq)  AgBr(s) + K+ (aq) + NO3- (aq)

79 Types of Gravimetric Methods
Gravimetry: is a method in which the signal is a mass or change in mass to find the amount (or concentration) of analyte in the sample. Types of Gravimetric Methods  precipitation gravimetry A gravimetric method in which the signal is the mass of a precipitate. Fe3+ + OH- → Fe(OH)3 →Fe2O3 volatilization gravimetry A gravimetric method in which the loss of a volatile species gives rise to the signal. In determining the moisture content of food, thermal energy vaporizes the H2O. The amount of carbon in an organic compound may be determined by using the chemical energy of combustion to convert C to CO2. CaCO3 (k)→CaO (k) + CO2(g) electrogravimetry A gravimetric method in which the signal is the mass of an electrodeposit on the cathode or anode in an electrochemical cell.  particulate gravimetry  the analyte is determined following its removal from the sample matrix by filtration or extraction. The determination of suspended solids is one example of particulate gravimetry.

80 Quantitative Calculations In precipitation gravimetry
the relationship between the analyte and the precipitate is determined by the stoichiometry of the relevant reactions. Fe3+ + OH- → Fe(OH)3 →Fe2O3 Grams of analyte = k ´ grams of precipitate Gravimetric factor : is a stochiometric ratio between the analyte and its precipitate Formula weight of Fe GF = x molecular weight of Fe2O3 2x 56 Mass of the Fe = the mass of the precipitate x 160

81 Quantitative Calculations In precipitation gravimetry
the relationship between the analyte and the precipitate is determined by the stoichiometry of the relevant reactions. mass of the analyte X % X (the percentage of analyte) = x 100 sample mass Grams of analyte = k ´ grams of precipitate Gravimetric factor : is a stochiometric ratio between the analyte and its precipitate a Formula weight of the analyte GF = x b molecular weight of the final precipitate Mass of X analyte = the mass of the precipitate x GF

82 An ore containing magnetite, Fe3O4, was analyzed by dissolving a 1
An ore containing magnetite, Fe3O4, was analyzed by dissolving a –g sample in concentrated HCl, giving a mixture of Fe2+ and Fe3+ . After adding HNO3 to oxidize any Fe2+ to Fe3+ the resulting solution was diluted with water and the Fe3+ precipitated as Fe(OH)3 by adding NH3. After filtering and rinsing, the residue was ignited, giving g of pure Fe2O3. Calculate the %w/w Fe3O4, in the sample.

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84 An impure sample of Na3PO3 weighing 0
An impure sample of Na3PO3 weighing g was dissolved in 25 mL of water. A solution containing 50 mL of 3% w/v mercury(II) chloride, 20 mL of 10% w/v sodium acetate and 5 mL of glacial acetic acid was then prepared. The solution containing the phosphite was added dropwise to the second solution, oxidizing PO3 3– to PO4 3– and precipitating Hg2Cl2. After digesting, filtering, and rinsing, the precipitated Hg2Cl2 was found to weigh g. Report the purity of the original sample as %w/w Na3PO3 Phosphorus has an oxidation state of +3 in PO3 3– and +5 in PO4 3–; thus, oxidizing PO3 3– to PO4 3– requires two electrons. The formation of Hg2Cl2 by reduction of HgCl2 requires 2 electrons as the oxidation state of each mercury changes from +2 to +1. Since the oxidation of PO3 3– and the formation of Hg2Cl2 both require two electrons, we have Moles Na3PO3 = moles Hg2Cl2

85 An impure sample of Na3PO3 weighing 0
An impure sample of Na3PO3 weighing g was dissolved in 25 mL of water. A solution containing 50 mL of 3% w/v mercury(II) chloride, 20 mL of 10% w/v sodium acetate and 5 mL of glacial acetic acid was then prepared. The solution containing the phosphite was added dropwise to the second solution, oxidizing PO3 3– to PO4 3– and precipitating Hg2Cl2. After digesting, filtering, and rinsing, the precipitated Hg2Cl2 was found to weigh g. Report the purity of the original sample as %w/w Na3PO3 Moles Na3PO3 = moles Hg2Cl2

86 Soru: to find the %w/w of NaCl in a mixture, 0,9532 g sample is disolved in pure water and precipitated with AgNO3. After drying the AgCl precipitate ie weighed 0,7033g. What is the %w/w of NaCl in a mixture? (NaCl: 58,44 AgCl: 143,32)

87 A typical gravimetric analysis procedure may be divided into five stages: sample pretreatment; precipitation; filtration; drying and ignition; weighing. 1- sample pretreatment 2 - precipitation; 3- filtration; 5- drying and ignition; 6- weighing.

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89 Çökelek ve çöktürücülerin özellikleri.
Precipitant A reagent that causes the precipitation of a soluble species. Must be selevtive for one analyte. Precipitate: is the product of a simple reaction between the analyte and precipitant. The precipitate must be formed quantitatively and within a reasonable time. Its solubility should be low enough for a quantitative separation to be made. It must be readily filterable and, if possible, have a known and stable stoichiometric composition when dried so that its weight can be related to the amount of analyte present. Failing this, it must be possible to convert the precipitate to a stoichiometric weighable form (usually by ignition).

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92 Precipitates form in two ways; by nucleation and by particle growth.
The theoretical and experimental details of precipitation gravimetry Precipitates form in two ways; by nucleation and by particle growth. Nucleation : A few ions, atoms or molecules come together to form a stable solid. Particle growth is the addition of new preciptates onto existing nucleus.. If nucleation predominates, a large number of very small particles results, if particle growth predominates a smaller number of larger particles is obtained. Solutions with a large, positive value of relative supersaturation (RSS) show high rates of nucleation, producing a precipitate consisting of numerous small particles. When RSS is small, precipitation is more likely to occur by particle growth than by nucleation.( smaller number of larger particles is obtained)

93 Controlling Particle Size
Following precipitation and digestion, the precipitate must be separated from the supernatant solution and freed of any remaining impurities, including residual solvent. These tasks are accomplished by filtering, rinsing,and drying the precipitate. The size of the precipitate’s particles determines the ease and success of filtration. Smaller, colloidal particles are difficult to filter because they may readily pass through the pores of the filtering device. Large, crystalline particles, however, are easily filtered. A solute’s relative supersaturation, RSS, can be expressed as Q is the solute’s actual concentration, S is the solute’s expected concentration at equilibrium, Q – S is a measure of the solute’s supersaturation when precipitation begins.3 A large, positive value of RSS indicates that a solution is highly supersaturated. Such solutions are unstable and show high rates of nucleation, producing a precipitate consisting of numerous small particles. When RSS is small, precipitation is more likely to occur by particle growth than by nucleation.

94 Colloidal solution: the particle size are in the range of 10-7-10-4 cm
Colloidal solution: the particle size are in the range of cm. colloidal solutions are genereally not filterable. Crystalline suspensions. Particle size are around mm, they have the tendency to precipitate. A precipitate’s solubility usually increases at higher temperatures, and adjusting pH may affect a precipitate’s solubility if it contains an acidic or basic anion. Temperature and pH, therefore, are useful ways to increase the value of S. Conducting the precipitation in a dilute solution of analyte, or adding the precipitant slowly and with vigorous stirring are ways to decrease the value of Q. When RSS is higher, colloidal solutions will form, when RSS is lower crystalline solutions will form

95 Colloidal solution: coagulation
coagulation The process of smaller particles of precipitate clumping together to form larger particles. Heating and string. Peptization İs a process by which a coagulated colloid returns to smaller particles. It could be happen when preciptate is being washed. HNO3, HCl, NH4Cl gibi elektrolitler eklenir.

96

97

98

99 A mg sample of an organic compound known to contain Cl is burned in pure O2 and the combustion gases collected in absorbent tubes. The tube used to trap CO2 increases in mass by mg, and the tube for trapping H2O shows a 13.7-mg increase. A second sample of mg is treated with concentrated HNO3 producing Cl2, which subsequently reacts with Ag+, forming mg of AgCl. Determine the compound’s composition, as well as its empirical formula.

100 Karışık kristal oluşumu
Çökeltinin Saflığı Normal olarak çözeltide kalması istenen bileşiklerin çökeltiye geçmesi safsızlıklara, ürün kütlesinin yanlış tartılmasına dolayısıyla analizde hataya neden olur. Yüzey Adsorpsiyonu normal koşullarda çözünen bileşiğin çöken teneciklerin yüzeyinde tutunmasıdır. Koloidal çökeleklerde görülür. Yıkama, Yeniden çötürme ile azaltılabilir. Karışık kristal oluşumu kristalin yapısında bulunan bir iyonun yerine ortamda bulunan başka bir iyonun yer değiştirerek çökmesidir. Hapsetme ve Mekanik sürüklenme kristaller arasındaki boşluklarda bir bileşiğin kalmasıdır. Yavaş çötürme ve bağıl aşırı doygunluk kontrol edilerek azaltılır.

101 Titration Titration is a procedure for determining the concentration of a solution by allowing a carefully measured volume to react with a standard solution of another substance, whose concentration is known. By finding the volume of the standard solution that reacts with the measured volume of the first solution, the concentration of the first solution can be calculated. equivalent point The point that all reactants are consumed, Stoichiometric mol numbers of both reactants are equal. an indicator a compound that change its color around equivalent point. such as phenolphthalein, is colorless in acidic solution but turns pink in basic solution.

102

103

104 Calculations in the volumetric titrimetry
Mol number m n = MA Molarity n M= mol/L V

105 Calculations in the volumetric titrimetry
aA + bB ↔ cC dD a mol A react with b mol B When A is a standard (titrant) the volume of A used in the titration and its molarity can be used to calculate the mol number of B

106

107 A 25.0 mL sample of vinegar (dilute acetic acid, ) is titrated and found to react with 94.7 mL of M NaOH. What is the molarity of the acetic acid solution?

108 Soru: antiasit ilaç tabletlerinin anabileşeni CaCO3 tür
Soru: antiasit ilaç tabletlerinin anabileşeni CaCO3 tür gr olarak tartılan bir tablet HCl ile titre edildiğinde, reaksiyonun tamamlanması için 38.5 ml 0.200M HCl harcandığına göre tablet içindeki CaCO3 yüzdesi nedir? CaCO HCl → Ca CO Cl- + H2O

109 soru: 0,2879g sodyum okzalatı (Na2C2O4) asidik çözeltide aşağıdaki redoks tepkimesine göre titre etmek için 25,12mL KMnO4 çözeltisi harcandığına göre KMnO4 ün molaritesi nedir? C2O MnO4- → Mn CO2

110 Gravimetric Titrimetry Coulometric titrimetri
Titrimetric Analysis konsantrasyonu bilinen bir çözeltinin analit ile reaksiyona giren miktarının ölçümüne dayanan kantitatif analiz metotlarıdır. Standart çözelti reaksiyon tamamlanıncaya dek ortama yavaş yavaş eklenir. Volumetry Gravimetric Titrimetry Coulometric titrimetri Standart reaktifin hacminin ölçülmesi temeline dayanan bir titrimetrik metottur Standart reaktifin kütlesinin ölçülmesine dayanan titrimetrik metottur Analit ile bir reaksiyonun tamamlanması için gerekli kulon cinsinden yük miktarının ölçüldüğü titrimetrik metottur. - İndirgenme-Yükseltgenme reaksiyonları - Asit Baz reaksiyonları - Kompleks oluşum reaksiyonları - Çöktürme titrasyonları

111 end point The point in a titration where we stop adding titrant.
Titrant: The reagent added to a solution containing the analyte and whose volume is the signal. titration: is a process in which a standard reagent is added to a solution of an analyte until the reaction between the analyte and reagent is completed. equivalence point The point in a titration where stoichiometrically equivalent amounts of analyte and titrant react. Indicator A colored compound whose change in color signals the end point of a titration. end point The point in a titration where we stop adding titrant. titration error The determinate error in a titration due to the difference between the end point and the equivalence point. Veq: Venepoint:

112 Acids and Bases

113 Acids and Bases Acids; Have a sour taste,
dissolve metals such as zinc and carbonate minerals change color of litmus to red Acetic acid in vinegar, Citric acid in lemons Bases Have a bitter taste, Have a slippery feel change color of litmus to blue, React with dissolved metal to form prepiciate Household cleaning products

114

115 Brønsted-Lowry Acid-Base
Acid-Base Definitions Arrhenius Acid-Base Definition Brønsted-Lowry Acid-Base Lewis acid-base

116 Arrhenius Acid-Base Definition (1884)
An acid is a substance that contains hydrogen and dissociates to produce Hydrogen ion : H+ HCl(aq)  H+(aq) + Cl-(aq) A base is a substance that contains the hydroxyl group and dissociates to produce Hydroxide ion : OH – NaOH (aq)  Na+ (aq) + OH -(aq) Neutralization is the reaction of an H+ ion from the acid and the OH - ion from the base to form water, H2O H+(aq) + OH-(aq) <=> H2O(l)

117 Brønsted-Lowry Acid-Base Definition (1923)
An acid is a species having a tendency to donate an H+ ion. HCl H2O  Cl– H3O+ A base is a species having tendency to accept an H+ ion. NH H2O  NH OH- The Conjugate Pairs in Some Acid-Base Reactions Conjugate Pair Acid Base Base Acid

118 question : show the conjugated acid base pairs in the reactions below
In the Brønsted-Lowry perspective, one species donates a proton and another species accepts it: an acid-base reaction is a proton transfer process. question : show the conjugated acid base pairs in the reactions below HF H2O  F– H3O+ H2PO4– OH–  HPO42– H2O NH CO32–  NH HCO3–

119 The Lewis acid-base definition :
A base is any species that donates an electron pair An acid is any species that accepts an electron pair.

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121

122 Strengths of Acids Strong Acids; An acid that completely ionized in water, is called as a strong acid HCl(aq) + H2O  H3O+(aq) + Cl-(aq) Weak acid is an acid that partly ionized in water. CH3COOH (aq) + H2O CH3COO-(aq) + H3O+(aq)

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124 Percent Ionization HA + H2O ↔ H3O+ + A- [H3O+] from HA
Degree of ionization = [H3O+] from HA [HA] originally Percent ionization = [H3O+] from HA [HA] originally x 100%

125 Strong acids. 1. The hydrohalic acids HCl, HBr, and HI 2. Oxoacids in which the number of O atoms exceeds the number of ionizable H atoms by two or more, such as HNO3, H2SO4, HClO4 Weak acids. 1. The hydrohalic acid HF 2. Those acids in which H is bounded to O or to halogen, such as HCN and H2S 3. Oxoacids in which the number of O atoms equals or exceeds by one the number of ionizable H atoms, such as HClO, HNO2, and H3PO4 4. Organic acids (general formula RCOOH), such as CH3COOH and C6H5COOH

126 NaOH (aq)  Na+ (aq) + OH -(aq)
Strong bases. A base that completely ionized in water, is called as a strong base. Soluble compounds containing O2- or OH- ions are strong bases. NaOH (aq)  Na+ (aq) + OH -(aq) 1) M2O or MOH, where M= Group 1A(1) metals (Li, Na, K, Rb, Cs) 2) MO or M(OH)2, where M = Group 2A(2) metals (Ca, Sr, Ba) [MgO and Mg(OH)2 are only slightly soluble, but the soluble portion dissociates completely.] A weak base is a base that partly ionized in water. Many compounds with an electron-rich nitrogen are weak bases (none are Arrhenius bases). The common structural feature is an N atom that has a lone electron pair in its Lewis structure NH3(g) +H20(l)  NH4+ (aq) + OH -(aq) 1) Ammonia (:NH3) 2) Amines (general formula RNH2, R2NH, R3N), such as CH3CH2NH2, (CH3)2NH, (C3H7)3N, and C5H5N

127

128 The Meaning of Ka, the Acid Dissociation Constant
Ka is the equilibrium constant of the ionization reaction of a weak acid. Kb represents the ionization constant of a base.

129

130 Kw = [H3O+][OH-] = 1.0 x 10-14 (at 25°C)

131 The pH Scale The pH is defined as the negative logarithm in base 10, of the hydronium ion concentration pH = - log[H3O+] The pOH is defined as the negative logarithm in base 10, of the hydroxyl ion concentration pOH = - log[OH-] pH of an acidic solution < 7.00 pH of a neutral solution = 7.00 pH of a basic solution > 7.00

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133

134 Calculating [H3O+], pH, [OH-], and pOH Strong and weak acid (or base)
Strong acid (or base) Weak acid (or base) Strong and weak acid (or base) [H+] = acid concentration calculate [H+] from Ka [H+] is generally equal to strong acid (effect of weak acid neglect unless strong acid is too dilute)

135 question : What is the pH of a solution that contains 10-2 M hydronium ion ?
question : Calculate the [H3O+], pH, [OH-], and pOH of M hydrochloric acid solutions at 25°C.

136 question : The weak acid hypochlorous acid is formed in bleach solutions. What is the [H3O+] of a M HClO solution? Ka = 3.5 x 10^-8

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138 Buffer solution is a solution whose pH changes only very slightly upon the addition of small of either an acid or a base. Buffer solutions contain a weak acid and its conjugate base ( its salt) or a weak base and its conjugate acid ( its salt).

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140

141 question : calculate the the pH of a buffer solution containing 0
question : calculate the the pH of a buffer solution containing M NH3 and M NH4Cl (for NH3 Kb = 1.74x 10-5) NH3 +H2O  NH OH-

142 question: calculate the ph of the 0.01 M sodium acetat solution.
Hidrolysis Salts of the weak acids (or weak bases) react with water to form the weak acid (or weak base). Salt Water ↔ weak acid + OH- equilibrium constant of this reaction is Kh=Kw/Ka the pH of the solution can be calculated from Kh. question: calculate the ph of the 0.01 M sodium acetat solution. For acetic acid, Ka= 1.8x10-5

143 Polyprotic Acids Phosphoric acid: A triprotic acid.
H3PO4 + H2O ↔ H3O+ + H2PO4- Ka = 7.1x10-3 H2PO4- + H2O ↔ H3O+ + HPO42- Ka = 6.3x10-8 HPO42- + H2O ↔ H3O+ + PO43- Ka = 4.2x10-13

144 Ionization Constants of Some Polyprotic Acids

145 Phosphoric Acid Ka1 >> Ka2
All H3O+ is formed in the first ionization step. H2PO4- essentially does not ionize further. Assume [H2PO4-] = [H3O+]. [HPO42-] ≈ Ka2 regardless of solution molarity.

146 Calculating Ion Concentrations in a Polyprotic Acid Solution.
For a 3.0 M H3PO4 solution, calculate: (a) [H3O+]; (b) [H2PO4-]; [HPO42-] (d) [PO43-] H3PO H2O ↔ H2PO H3O+ Initial conc. 3.0 M 0 0 Changes -x M +x M +x M Eqlbrm conc. (3.0-x) M x M x M

147 Acid Base titrations A titration in which the reaction between the analyte and titrant is an acid–base reaction. Standard reactants: acid–base titrations were conducted using H2SO4, HCl, and HNO3 as acidic titrants, and K2CO3 and Na2CO3 as basic titrants. Indicator : A colored compound whose change in color signals the end point of a titration. End points were determined using visual indicators such as litmus, which is red in acidic solutions and blue in basic solutions, Acidimetry: Determination of the Base content of a sample by titrating strong acid solution. Diluted solutions of HCl, H2SO4, HClO4 are used as a titrant. Since HNO3 gives some extra reactions, it can not be used for acidimetry. Alkalimetry: Determination of the acid contents of a sample by titrating with a strong base solutions like NaOH, KOH ve Ba(OH)2

148 Visual Indicators for Acid-base Titrations
an acid–base indicator are the weak organic acids. the weak acids and bases derivatives of organic dyes can serve as a useful means for determining the end point of a titration. Because such compounds have at least one conjugate acid–base species that is highly colored, Indicator A colored compound whose change in color signals the end point of a titration. an acid–base indicator changes color with in changing the pH of the solution.

149 In general terms a visual indicator is a compound which changes from one colour to another as its chemical form changes with its chemical environment If the indicator is present in an environment where a titration reaction generates or consumes the X species, the indicator will change with the concentration of X in the solution and the colour of the solution will be determined by the ratio [InB]/[InA]. As a general guide, the eye will register a complete change from one colour to the other when this ratio changes from 10:1 to 1:10.

150 The pH at which an acid–base indicator changes color is determined by its acid dissociation constant. For an indicator that is a monoprotic weak acid, HIn, the following dissociation reaction occurs HIn(aq) + H2O(l)↔H3O+(aq) + In–(aq) For example, the acid-base indicator methyl orange has a pKIn of 3.7 and will thus change colour over the pH range 2.7–4.7. The ultimate sharpness of the end point will further depend upon the rate at which pX is changing at the end point of the titration.

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152

153 Acid-base Titration Curves
titration curve: A graph showing the progress of a titration as a function of the volume of titrant added. A titration curve provides us with a visual picture of how a property, such as pH, changes as we add titrant Titrating Strong Acids and Strong Bases Titrating a Strong Base with a Strong Acid Titrating a StrongAcid with a Strong Base Titrating a Weak Acid with a Strong Base Titrating a Weak Base with a Strong Acid

154 Titration Curves Titrating a Strong Acid with a Strong Base
starts with a low pH, then pH changes less till equivalent point then there will be sudden change (increase) at the equivalent point. Titrating a Strong Base with a Strong Acid The curve starts at the basic region, till equivalent point pH decrease less but at the equivalent point sudden change (decrease) will occur.

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156

157 Titration Curves Titrating a Weak Acid with a Strong Base
Titrating a Weak Base with a Strong Acid

158

159 the titration curve when titrating a diprotic weak acid, H2A, with a strong base.

160 pH Calculations in the Titrating of a Strong Acid with a Strong Base
Before equivalence point At the equivalence point After equivalence point

161 question: 50. 0ml 0. 050 M HCl solutrion is being titrated with 0
question: 50.0ml M HCl solutrion is being titrated with M NaOH, calculate the pH when 0 ml base added, 10 ml base added, 20ml base added, 25ml base added, 30 ml base added, and 40 base added, Draw the titration curve.

162 pH Calculations in the Titrating of a weak Acid with a Strong Base
Buffer solution A solution containing a conjugate weak acid/weak base pair that is resistant to a change in pH when a strong acid or strong base is added. Buffer capacity is the mol number of a stronge acid or base needed to add for changing the pH 1,0L solution in 1 unit The pH of a buffer changes within the range of pH = pKa ± 1 Question: calculate the the pH of a solution containing M NH3 and M NH4Cl (for NH3 Kb = 1.74x 10-5) NH3 +H2O  NH OH-

163 Titrating of a weak Acid with a Strong Base
Hidrolysis Salts of the weak acids (or weak bases) react with water to form the weak acid (or weak base). Salt Water ↔ weak acid + OH- equilibrium constant of this reaction is Kh=Kw/Ka the pH of the solution can be calculated from Kh. Question : calculate the pH of a 0.01 M sodium acetat solution. Ka= 1.8x10-5

164 pH Calculations in the Titrating of a weak Acid with a Strong Base
. Adding 0ml base Calculate the pH from Ka of the weak acid Before the Equivalence point Calculet the pH of the buffer solution At the Equivalence point Calculate pH of the salt of the weak acid (Hydrolysis) After the Equivalence point Calculate the pH from the concentraion of the base (not consumed in the reaction)

165 Soru: 50ml 0. 10 M acetic acid is being titrated with 0. 10 M NaOH
Soru: 50ml 0.10 M acetic acid is being titrated with M NaOH. calculate the pH when. 0ml base added , 10 ml base added 45 ml base added 50 ml baz ilavesi 51 base added 55 ml base added Ka= 1.8x10-5

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167 Titrasyonda İndikatörden gelen Hatalar
Belirli hatalar Rastgele hatalar indikatörün renk değişim pH aralığının titrasyonun eşdeğerlik noktasındaki pH ının faklı olması sonucu olur. Uygun indikatör seçimi, tanık deney düzeltmesi ile azaltılır. renk değişimi izlenirken göz yanılgılarından kaynaklanır.

168 complexometric titrations
A complexometric titration is based on the essentially stoichiometric reaction of a complexing agent with another species to form a complex species that is only slightly dissociated and that is soluble in the titration medium. Complex The product of the complexation reaction is called a metal–ligand complex. Ligant A Lewis base that binds with a metal ion Chelat bir metalin bir ligantla bağlanarak oluşturduğu halkalı kompleks tir formation constant The equilibrium constant for a reaction in which a metal and a ligand bind to form a metal–ligand complex (Kf).

169

170 EDTA The most widely use ligands is ethylenediaminetetraacetic acid, EDTA, forms strong 1:1 complexes with many metal ions. Dissosiation constants of EDTA: K1= 1.02x10-2 K2= 2.14x10-3 K3= 6.92x10-7 K4= 5.50x10-11

171

172 EDTA çözeltilerinde α değerlerinin hesaplanması
EDTA Hidrojen iyonlarını kaybederek şu türlere iyonlaşır [Y4- ]+[HY3-]+[H2Y2-]+[H3Y-]+[H4Y] K1= 1.02x10-2 K2= 2.14x10-3 K3= 6.92x10-7 K4= 5.50x10-11 Y4- nin çözeltideki mol kesri [Y4-] α4= CEDTA CEDTA= [Y4- ]+[HY3-]+[H2Y2-]+[H3Y-]+[H4Y] Buradan K sabitleri kullanılarak K1K2K3K4 α4= [H+]4 + K1[H+]3-+ K1K2[H+]2- + K1K2K3[H+] + K1K2K3K4 α4 = olarak bulunur EDTA Metal İyonları Kompleksleri Mn Y4- ↔ MYn-4 [MYn-4 ] KMY = [Mn+] [Y4-] K’MY (durum sabiti) K’MY = = α4 KMY [Mn+] CEDTA

173 Calculate the Concentration of Ni2+ in a soltion which prepared as mixing 50.0ml M Ni2+ and 50.0mlml M EDTA at pH= 3 At pH=3 , α4= 2.5x KNiY=4.2x1018

174 EDTA titrasyon eğrileri
Verilen pH değeri için durum sabiti değeri bulunur hesaplamalarda kullanılır. Eşdeğerlik noktası öncesinde ortamda metal iyonu fazlası vardır ve harcanmadan kalan metal iyonu konsantrasyonu hesaplanır. Eşdeğerlik noktasında ortamda sadece kompleks vardır ve bir miktar ayrışır, ayrışan metal iyonu konsantrasyonu durum sabitinden hesaplanır. Eşdeğerlik noktası sonrasında EDTA fazlası vardır ve artan EDTA konsantrasyonu durum sabitinde yerine konarak metal iyonu konsantrasyonu hesaplanır.

175 50.0ml 0.0500 M Mg2+ nın 0.0500 M EDTA ile titrasyonunda pH=10 na tamponlanıyor,
0ml, 5.0ml, 50.0ml ve 51.0 ml EDTA ilaveleri için Mg2+ konsantrasyonunu hesaplayınız ve titrasyon eğrisini çiziniz. PH=10 için α4= 3.5x10-1 Kol= 6.2 x 108

176 EDTA titrasyonları için İndikatörler
Genel olarak metal iyon indikatörleri kullanılır. Bunlar metal iyonlarına bağlandığında renk değiştiren organik boyalardır. MetalIn EDTA → MetalEDTA In Renk renksiz renksiz renk 2

177 substitution titrations
Chelometric titrations may be classified according to their manner of performance: direct titrations, back titrations, substitution titrations, or indirect methods. direct titrations back titrations substitution titrations indirect methods

178 0,300 g metal wire is being dissolved in nitric acid and diluted to 100,0ml with pure water ml sample is taken from this solution and added M EDTA and then neutralized with NaOH. After that the pH of the solution is buffered to pH=5.5. and excess EDTA is back titrated with ml M Zn2+. Calculate the Ni2+ percent in the metal wire. (Ni: 58,71g/mol EDTA:372,0g/mol)

179 Application of Equilibrium Calculations to Complex Systems
when aqueous solutions contain several species that interact with one another and water that yield two or more simultaneous equilibria. PbS ↔ Pb2+ + S2- S2- + H2O ↔ HS- + OH- HS- + H2O ↔ H2S + OH- 2 H2O ↔ H3O+ + OH-

180 Steps for solving problems involving several equilibria
Write all chemical equations and balance them Write all equilibrium constant wxpressions. State (undrline) which quantity (unknown) you want to find (solve). Write mass balance expression for the system. Write the charge balance equation (IF possible) Compare the number of equations and the number of unknowns. Make suitable approximations to simplify the algebra. Solve the algebraic equations, find the unknown defined at step 3. Check the validity of approximations.

181 mass balance equation: (which is simply a statement of the conservation of matter.)
An equation stating that matter is conserved, and that the total amount of a species added to a solution must equal the sum of the amount of each of its possible forms present in solution. charge balance equation: (is a statement of solution electroneutrality.) An equation stating that the total concentration of positive charge in a solution must equal the total concentration of negative charge. Total positive charge from cations = total negative charge from anions.

182 Write the mass balance equation for 1 liter of 0
Write the mass balance equation for 1 liter of mol H3PO4 aqueous solution.   Write charge balanse equation for a solution which contains H+, OH-, K+, H2PO4-, HPO42- and PO43-

183 Calculate the Hg22+ cocentration in a saturated Hg2Cl2 solution. Ksp= 1.2x10-18 Kw=1x10-14  

184 Calculate the molar solubility of Mg(OH)2 in water. Ksp Mg(OH)2 = 7
Calculate the molar solubility of Mg(OH)2 in water. Ksp Mg(OH)2 = 7.1x10-12 Kw=1x10-14 Calculate the molar solubility of Fe(OH)3 in water. Ksp Fe(OH)3 = 2.0x Kw=1x10-14

185 Calculate the solubility of calcium oxalate in a solution which the Hydronium ion cocentration is 1.0 x For CaC2O4 Ksp= 2.3 x for H2C2O4 Ka1= 5.36 x 10-2, Ka2= 5.42 x Kw=1x10-14

186 Calculate the solubility of AgBr in 0. 1 M NH3 solution
Calculate the solubility of AgBr in 0.1 M NH3 solution. For AgBr Ksp= 5.2 x for Ag(NH3)+ Kformation oluşum= 2 x 103 for Ag(NH3)2 Kformation= 6.9 x 103 for NH3 Kb= 1.76 x 10-5

187 Soru: 0.1 M Pb2+ ve 0.1 M Fe2+ içeren bir çözeltiye H2S eklenerek Pb2+ ve Fe2+ iyonları birbirinden ayrılması için gerekli koşulları belirleyiniz. Kçç(PbS)=3x10-28, Kçç(FeS)=8x H2S için K1=9.6x10-8 K2=1.3x10-14

188 Calculate the solubilty of HgS in water by using all equations which occur. for HgS Ksp = 5 x Kw= 1.0 x 10-14, for H2S Ka1= 9.6x10-8 Ka2= 1.3x10-14


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