...General Chemistry II Professor: Dr. Yang Yang Turned in: April 9, 2014 Experiment #6 The Properties of Buffers Abstract In this experiment the pH of fours solutions was recorded and identified as acidic, basic, or neutral. A buffer system of 0.10 M ammonium ion (NH4+) and 0.10 M ammonia (NH3). This buffer was made three times: once with equal parts ammonium ion and ammonia, next it was diluted to double the volume, and finally it was prepared with an addition of HCl. The pH was recorded to calculate the Ka and pKa values. The most accurate Ka value recorded was the second from B2 which was 5.13x10-10. Using this Ka value the appropriate volumes of ammonium ion and ammonia were calculated to make a buffer solution with a pH of 8.7. The final volumes were 15.9 mL of ammonium ion and 4.1 mL of ammonia. Part A solution pH acidic, basic, neutral? 0.100 M NaHSO4 1.8 acidic 0.100 M Na2CO3 11.2 basic 0.100 M NH3 10.9 basic 0.100 M NaCI 6.8 neutral Net Ionic Reaction NaHSO4 Na+ + HSO4- + H2O --> Na+ (SO4)2- + H3O+ HSO4- + H2O --> (SO4)2- + H3O+ Na2CO3 Na2CO3 + H2O --> NaHCO3 + NaOH 2Na+ + CO32- + H2O --> Na+ + HCO3- + Na+ + OH- CO32- + H2O --> HCO3- + OH- NH3 NH3 + H2O --> NH4-+ OH- NaCI NaCI + H2O --> H2O + Na+ + Cl- NaCI--> Na+ + Cl- Part B calculations attached on next page Ka Values Part Ka pKa B1 6.3x10-10 9.2 B2 5.13x10-10 9.29 B3 3.98x10-10 8.4 Discussion: All of the Ka values were...
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...BUFFER SOLUTION Buffer solution is a solution which resist any change in its pH an addition of strong acid or alkali. Types 1 Mixture of weak acids with their salt with strong base i.e. (weak acid + salt of weak acid , conjugated base) 2 Mixture of weak bases with their salt with strong acid i.e. (weak base + salt of weak acid , conjugated acid) Examples: H2CO3/NaHCO3(Bicarbonate buffer) (Carbonic acid and Sodium Carbonate) CH3COOH/CH3COONa(Acetate buffer) (Acitic acid and Sodium acetate) Na2HPO4/NaH2PO4(phosphate buffer) Buffer capacity: Buffering capacity is the no. of grams of strong acids or alkali which is necessary for a change in pH of one unit of one lit. of buffer solution. Axn: When HCl or NaOH is added to acetate buffer * CH3COONa + HCl→CH3COOH + NaCl * CH3COOH + NaOH→CH3COONa + H2O Thus change in pH is minimized BUFFER OF THE BODY FLUIDS Cellular metabolism predominantly yields acids so it is approcipriate that body buffer has buffering capacity to absorb acids are first line of defense against acid load. a Bicarbonate buffer system ( H2CO3/NaHCO3) % of buffering capacity, Plasma- 65% Whole body- 40% CO2 and H2CO3 can freely diffuse across the cell membrane and vascular capillary epithelium. Regulation, Base constituents-kidney (metabolic component) Acid constituents –respiration (Respiratory) Salt / Acid – 20 b. Phosphate buffer system (Na2HPO4/NaH2PO4) Primary intracellular buffer, its concentration...
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...Abstract Buffer solutions were prepared and their pH measured to determine their buffering capacity. Three buffer solutions were utilized; an undiluted buffer, a diluted buffer solution with 10ml water and a diluted buffer solution with 18ml water. In the undiluted buffer solution there was minimal pH change with a high of 6.78 and a low of 6.47. In the buffer solution in which 10ml of water was added there was minimal pH change with a high of 6.78 and a low of 6.23. In the buffer solution in which 18ml water was added there was significant change in pH with a high of 6.1 and a low of 2.27. Introduction A buffer solution is a solution that is made up of water and a chemical which gives it unique properties with regard to its pH. The chemical is referred to as buffer agent. The buffer agent resists changes in pH when exposed to bases and acids. The aforementioned property makes it useful in dealing with various chemical accidents, protecting sensitive equipment and balancing internal processes of a number of living things. A buffer agent dissolved in water makes a buffer solution. It is constituted of (HA) an acid and a conjugate base (A-) mixed in water. Once there exists a chemical balance between HA and A- the addition of any bases or acids will be neutralized. This will result in little pH change of the solution. An increase in HA and A- as a result of the addition of bases or acids decreases the buffering capacity of the solution. This implies that the solution acts as...
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...Introduction Buffer is a solution that resists a change in pH when bases or acid are added. Solutions that are acidic contain high concentrations of hydrogen ions (H+) and have pH values less than seven. Buffer usually consist of a weak acid, and its conjugate base or a weak base and its conjugate acid. The function of buffer is to resist the changes in hydrogen ion concentration as a result of internal and environmental factor. This buffer experiment is important so that we relies the important of buffer in our life. Besides that, it is also important so that we master the buffer preparation techniques and can conduct the experiment ourselves without anyone to instruct us. Other than that, we got to learn how to operate a pH meter and we...
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...Acis CHEMICAL REACTIONS: ACID-BASE BUFFERS Short Overview Acids and bases represent two of the most common classes of compounds. Many studies have been done on these compounds, and their reactions are very important. Perhaps the most important reaction is the one in which an acid and base are combined, resulting in the formation of water (in aqueous solution) and a salt; this reaction is called neutralization. A buffer solution is a solution that contains both an acid and a salt containing the conjugate base anion in sufficient concentrations so as to maintain a relatively constant pH when either acid or base is added. In this experiment you will prepare a buffer solution and observe its behavior when mixed both with an acid and a base. You will also compare the behavior with that of solutions containing only the acid. Theory In his theory of ionization in the 1880’s, Svante Arrhenius defined acids are substances which form H+ and bases as substances which form OH- in water. He further defined a salt as a substance other than an acid or base which forms ions in aqueous solution. Such substances are thus capable of producing an electric current and are called electrolytes. The amount of electricity produced is directly proportional to the concentration of ions in solution. With regard to electrolytes we have learned previously that strong acids and strong bases ionize completely, and are therefore strong electrolytes because they...
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...conjugate acid. This proves the Henderson Hasselbalch equation. b. The addition of a strong acid would decrease the pH, since water is a neutral solution. It has nothing to account for the increase of H+ ions. The addition of a strong acid to the buffer, however, would generally not affect the pH. The buffer has a conjugate base which would be able to accept the excess of H+ ions, therefore not greatly effecting the pH. H3O+ would form, which would then react with A- to form HA and H2O. c. Diluting the acid would overall increase the pH of the solution. The dilution would cause an increase in volume, while the moles of H+ ions remains the same, therefore decreasing the concentration of H+ ions. If sufficiently diluted, the solution would become neutral with a pH of 7. d. The pH value of our most diluted buffer sample compared to our undiluted sample were not as similar as we would have expected. We believe that the difference in pH’s is due to the minimal time allowed for the undiluted buffer to reach equilibrium before having the pH measured. In addition to this, our pH meter was malfunctioning and had to be zero’d several times throughout the lab. The difference between the first and second dilutions was more appropriate for a buffer, showing...
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...pH Measurement and Buffer Preparation Quilao, M.H., Regua, R., Reinoso, L.A., Rojas, K.J., Sabalberino, E.M. Abstract In this experiment, phosphate buffer solution was prepared and the pH of the buffer and samples were determined through different liquid indicators and the pH meter. Also, the buffer capacity of the prepared buffer solution was calculated. The group was tasked to prepare a 250 mL phosphate buffer solution of pH 8.0 using dihydrogen phosphate ion (H2PO4) and primary sodium phosphate monohydrate (NaH2PO4.H2O). With the aid of 6.0 M HCl and 6.0 M NaOH, the pH of the buffer was adjusted while being recorded by the pH meter until it reached the desired pH. Afterwards, the buffer solution was introduced to Colorimetric Determination which used acid-base indicators. The buffer solution changed to color yellow when Thymol and Methyl red were added, blue when Bromophenol blue and Bromocresol green were included, purple for Bromocresol purple, pink for Phenol red and Phenolphthalein, and orange for Methyl orange. Introduction The measurement of the low concentration of hydrogen ions present in any biological process is expressed as pH. pH is used to measure the acidity and alkalinity of a solution. pH involves ionic activity, making it difficult to accurately predict the pH value of a solution. The pH is also known to greatly affect our biological system and any large changes could be dangerous, which is why there is a buffer present within our systems...
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...THE EFFECTS OF BUFFER PATTERNS ON THROUGHPUT IN CONWIP FLOW LINES: A SIMULATION STUDY Sunitiya Thuannadee Received: May 21, 2007; Revised: Sept 4, 2007; Accepted: Sept 10, 2007 Abstract This research was a simulation experiment which aimed to investigate the effects of buffer patterns on the throughput of lines controlled by a CONWIP release mechanism. The hypothetical lines simulated were stochastic 11-station flow lines with the middle station as the bottleneck. ANOVA tests were used for the analysis of the simulation output, followed by Duncan’s Multiple Range tests. There were 6 buffer patterns which were distinguished by the amount of total buffer capacity and the buffer allocation approaches. The experiment was done at three levels of protective capacity (PC); 0%, 20%, and 40%, and two levels of coefficient of variation (CV) of processing times; 0.05 and 0.50. When CV = 0.05, ANOVA tests revealed a significant difference (p < 0.01) among buffer patterns only for the lines with PC of 0%, whereas when PC = 20% and 40%, there were insignificant differences among buffer patterns. When CV = 0.50, ANOVA tests indicated significant differences (p < 0.01) among buffer patterns at all PC levels. The important suggestion is that appropriate allocation of limited buffer capacity, an addition of protective capacity, and a reduction of system variation could increase the throughput rates to the desired level. Keywords: Release mechanism, CONWIP, buffers, protective capacity, bottleneck ...
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...LOVELY PROFESSIONAL UNIVERSITY HOME WORK – I DOA: 9/7/2012 DoS: 9/17/2012 ------------------------------------------------------------------------------------------------------------------- Assignment COURSE- Modern Web Programming Tools and Techniques-I COURSE CODE- CAP618T SUBMITTED BY: SUBMITTED TO: Anil Kumar Miss. MANDEEP KAUR Roll-A24 Reg. - 11013165 Sec- D1R05 Q: 1 Take a JavaBeans Object named “Profession” with properties domain and expertise. Show the use of all 4 scope types on this object. Ans:- You just need to create a domain object as a JavaBeans property and the corresponding getter and setter methods. The framework will automatically initialize the domain object and transfers the form data. The UserAction class contains the following code. Public class UserAction extends ActionSupport { Private User user; Public UserAction() { Public String execute() { Return SUCCESS; } Public User getUser() { Return user; } Public void setUser(User user) { this. user=user; } } To refer the user attributes like name, age etc. we need to first get the user object and then access its properties. For example to access the user's age in the Action you need to use the following syntax. getUser().getAge(); public class User...
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...Labs Unit 4 Labs NT1210 8/4/14 Unit 4 Labs Lab Review: 4.1 – Page: 82 and 83 1. To eliminate the crossover issue, lower the amount of equipment and cost. Simplify a network. 2. To increase the maximum distance for a signal. If put after the maximum distance the signal may degrade. 3. The connection and processing speed. It also depends on the number of connections the computer or laptop will allow. Lab Review: 4.2 – Page: 85 1. A. Bend Radius: The minimum radius that a fiber optic cable can be bent without loss of light or impairment. A general rule that it be no less than 15 times the cable diameter B. To not affect a signal sent down the line. 2. The core/Glass Filament, Cladding, Buffer, Strengthener and Outer Jacket. Lab Review: 4.3 – Page: 90 1. Ease of installation, lack of certified fiber optic specialists and changes to the physical design of the network later on. 2. By limiting the devices needed depending on the distance and need of each network. Verify the number of access points needed before the start. Lab Review: 4.4 – Page: 95 1. By selecting a specific layer and testing the health you can definitively say the problem lies either below or above that layer. Example: test the Transport layers health if it is ok you know the problem is in the Application layer. 2 A. B. If the cable is damaged in any way it should be checked. -----------------------...
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...there for your entire family. Both work and family come with obligations and it is often difficult to prioritize between the two as both are very important and rely on each other. There are certain buffers that help dissipate work and family conflict. One of them is family composition. There is a lot covered under a family’s composition. Having close family and friends nearby can help a single working mother or father or even dual working parents juggle their work and family lives. Extra hands on deck are always a plus with busy families. Depending on the ages of the children of a family, younger children tend to provide more stressors while older children who need less are more stable and can do a lot for themselves which relieves potential stress off the parents. If both parents work, having set chores for each of them is a good way to even the playing field making sure neither parent is more overloaded than the other. A housekeeper would also be a great option to take some of that stress of their shoulders. The traditional gender roles are where the husbands work the long hours and the wives stay at home and take care of the children and do the housework. Sometimes conflict is created because of the work stress that the husband goes through where the wife does not. A good buffer for this is for the wife to enter the workforce as well, even if it’s simply...
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...Advantages of a successful buffer-stock scheme: Stable prices help maintain farmers’ incomes and improve the incentive to grow legal crops Stability enables capital investment in agriculture needed to lift agricultural productivity Farming has positive externalities it helps to sustain rural communitiesStable prices prevent excess prices for consumers – helping consumer welfare Problems with buffer stock schemes In theory buffer stock schemes should be profit making, since they buy up stocks of the product when the price is low and sell them onto the market when the price is high. However, they do not often work well in practice. Clearly, perishable items cannot be stored for long periods of time and can therefore be immediately ruled out of buffer stock schemes. Other problems are: Cost of buying excess supply can cause a buffer stock scheme to run out of cash A guaranteed minimum price might cause over-production and rising surpluses which has economic and environmental costs Setting up a buffer stock scheme also requires a significant amount of start up capital, since money is needed to buy up the product when prices are low. There are also high administrative and storage costs to be considered. The success of a buffer stock scheme however ultimately depends on the ability of those managing a scheme to correctly estimate the average price of the product over a period of time. This estimate is the scheme’s target price and obviously determines the maximum and...
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...against using a buffer stock scheme to stabilise the price of a commodity such as sugar or tin. A buffer stock is an intervention system that aims to limit the fluctuations of the price of a commodity. A commodity is a good that is traded, but usually refers to raw materials or semi-manufactured goods that are traded in bulk. In free markets agricultural prices fluctuates from year to year depending on the level of output affecting both the famers’ income and ability to make long term plans. In some cases this has led to setting up buffer stocks to ensure consistent supply and income to farmers. The authorities sell from the stock when harvests are poor and buy in stock when harvests are good. This prevents huge price increases in bad times and low famers’ incomes when harvests are good. One reason why using a buffer stock scheme to stabilise the price of a commodity such as sugar or tin is a good idea is that it prevents fluctuations in the price of a commodity. This is because when the output of a commodity increases or decreases the government will be able to buy the excess stock and store it, or release the stock that they have stored. This means that, in the case of sugar and tin, there will not be a shortage causing an increase in price because the government will be able to release stock that they have previously stored to maintain the output and price, therefore leading to no fluctuations in the price of sugar and tin. Another reason why using a buffer stock scheme...
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...//Example reads in employee data from user //data is not stored in an Employee object but is written into files using //Formatter //PrintWriter //BufferedWriter import java.io.FileWriter; import java.io.BufferedWriter; import java.io.PrintWriter; import java.io.File; import java.util.Formatter; import java.util.Scanner; class FileWriterDemo { public void buffEmployeeFileWriter() throws Exception { String fName; String lName; int id; boolean quit = false; boolean response = true; Scanner console = new Scanner(System.in); Scanner input = new Scanner(System.in); Formatter output = new Formatter("EmployeeFormatter.txt"); //opens the file for editing FileWriter file = new FileWriter("EmployeePrintWriter.txt"); PrintWriter print = new PrintWriter(file); //turn on append flag for EmployeeBufferedFileWriter.txt FileWriter fwriter2 = new FileWriter(new File("EmployeeBufferedFileWriter.txt"), true); BufferedWriter bfw = new BufferedWriter(fwriter2); try { while (quit != response) { System.out.print("Enter Employee First Name:\n"); fName = input.next(); System.out.print("Enter Employee Last Name:\n"); lName = input.next(); System.out.print("Enter Employee id:\n"); id = input.nextInt(); //Example using Formatter ...
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...Buffer solutions and common ion effect A buffer solution resists (or buffers) a change in its pH. That is, we can add a small amount of an acid or base to a buffer solution and the pH will change very little. How to calculate pH of buffer solution containing both acid and conjugate base? Dissociation constant definition 1.1 can be rearranged into [pic] or [pic] (note that due to sign change [A-] was moved to nominator). This is so called Henderson-Hasselbalch equation (or buffer equation). It can be used for pH calculation of solution containing pair of acid and conjugate base - like HA/A-, HA-/A2- or B+/BOH. For solutions of weak bases sometimes it s more convenient to use equation in the form [pic]15.3 Two common types of buffer solutions are : (1) a weak acid together with a salt of the same acid with a strong base. These are called Acid buffers e.g. CH3COOH + CH3COONa. (2) a weak base and its salt with a strong acid. These are called Basic buffers. e.g.NH4OH + NH4Cl. Let us illustrate buffer action by taking example of a common buffer system consisting of solution of acetic acid and sodium acetate (CH3COOH/CH3COONa). CH3COOH --- H+ + CH3COO– CH3COONa ---- Na+ + CH3COO- since the salt is completely ionised, it provides the common ions CH3COO– in excess. The common ion effect suppresses the ionisation of acetic acid. This reduces the concentration of H+ ions which means that pH of the solution is raised. Thus, a 0.1 M acetic acid solution has a pH...
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