Determining the concentration of acid in a given solution
Determining the concentration of acid in a given solution Planning 4 I have been given a sample of sulfuric (VI) acid solution with a concentration between 0.05 and 0.15 mol dm-³. I am going to find out the accurate concentration of the sulfuric acid. To find out the concentration of the acid I will react it with a known volume and concentration of a base and see how much base was needed to neutralise the acid. The acid is a strong acid which means that I know all the H+ ions have been disassociated and are in the solution. The H+ ions will react with the OH- ions in the alkali which will neutralise the solution. I am provided with solid, hydrated sodium carbonate with the formula Na2CO3·10H2O.1 This is a readily available base and I can dilute it down to achieve the concentration I want to react with the acid. The formula of the reaction that will take place is H2SO4 (aq) + Na2CO3 (aq) --> Na2SO4 (aq) + CO2 (g) + H2O (l) So 1 mole of H2SO4 reacts with 1 mole of Na2CO3. A titration will give me the most reliable and accurate results with the available equipment. To do my titration I will need: A Burette 7 I will need a burette to add the sodium carbonate to the sulfuric acid solution. The burettes provide me with very accurate results of volume of solution added. The class set of burettes measure 50cm3. I want to do a titration
UV-Visible Spectrophotometry
Name: Chu Ka Ki Student No.: 50555542 Group: 1 Date: 17-02-2005 Experiment: 2 BCH 2004 Principle of Analytical Chemistry Lab Report (Report One) Title: UV-Visible Spectrophotometry Aim: To determine phosphate composition in cola beverages by UV-Visible spectrophotometry and pH titrimetry. Introduction: UV-Visible spectrophotometry is one of the most important methods for the chemical analyze. Ultraviolet-Visible spectroscopy or Ultraviolet-Visible spectrophotometry (UV/VIS) involves the spectroscopy of photons (spectrophotometry). It uses light in the visible and adjacent near ultraviolet (UV) and near infrared (NIR) ranges. In this region of energy space molecules undergo electronic transitions. The method is used in a quantitative way to determine concentrations of an absorbing species in solution, using the Beer-Lambert law: where A is the measured absorbance, I0 is the intensity of the incident light at a given wavelength, I is the transmitted intensity, L the length of the cell, and c the concentration of the absorbing species. For each species and wavelength, ? is a constant known as the extinction coefficient. The absorbance A and extinction ? are sometimes defined in terms of the natural logarithm instead of the base-10 logarithm. Methodology: Colorimetric Analysis: At the beginning, 4cm3 decarbonated cola was transferred into a 100cm3
Enthalpy of formation of calcium carbonate
EXPERIMENT 6 Enthalpy of formation of calcium carbonate Objective To determine the enthalpy of formation of calcium carbonate Procedures A. Reaction of calcium with dilute hydrochloric acid . 1.0909 g of calcium metal was weighed out accurately. 2. 100 cm3 of approximately 1 M hydrochloric acid was pipetted.and placed in a plastic beaker. 3. The initial temperature of the acid was determined 4. The weighed calcium was added into the acid and stirred thoroughly with the thermometer until all the metal had reacted. 5. The maximum temperature attained by the solution was recorded. 6. The experiment was repeated with 1.0538g calcium metal. Results: Experiment no. 2 Mass of Ca used/ g .0909 .0538 Initial temp. of solution/ ? 27 26 final temp. of solution/ ? 55 52 Temperature change/ ? 28 26 Calculations and Discussion: . What does the term "heat of formation" of a substance mean? Heat of formation refers to the heat change when one mole of a substance is formed from its constituent elements is their standard states under standard conditions. 2. What are "standard conditions" for thermochemical calculations? Standard conditions is defined as elements or compounds appear in their normal physical states at a pressure of 1 atm (101325 Nm-2/760mmHg) and at temperature of 25 oC (298 K).Moreover, the solution should have unit activity(1mol dm-3 ). 3. Write
Determination of a Rate Equation
Determination of a Rate Equation Introduction: The rate of reaction is the rate of depletion of reactants or the formation of a product during a chemical reaction. It is expressed by units of concentration over the time taken for the reaction to take place. (Avogrados, 2010) Aim: To plan and carry out an experiment involving a graphical method to determine how the concentration of each component affect the rate of reaction in this reaction: 2HCl + Na2S2O3 --> 2NaCl + SO2 + S + H2O Background Information: Sodium thiosulphate and hydrochloric acid are both clear colourless solutions. They react together according to this equation: 2HCl + Na2S2O3 --> 2NaCl + SO2 + S + H2O When these solutions are mixed together, a yellow precipitate, sulphur, is produced. This causes the mixture to appear cloudy. The faster the rate of the reaction, the faster the solution appears cloudy. There are four basic factors that affect the rate of a reaction namely: Temperature, concentration/ pressure (in gases), physical state/ surface area of the reactants and the presence or absence of a catalyst [(Think Quest, 2008) and (WebChem, 2005)] Basic Idea: * Two sets of experiments will be carried out. In each case, the concentration for a single reactant will be varied * All other factors should remain constant * Conical flask containing the mixed reactants will be placed on a paper
Analysis of sulphur dioxide content in wine.doc
Analysis of sulphur dioxide content in wine Objective To determine the amount of sulphur dioxide, an antioxidant, present in wine by using volumetric analysis. Principle All free SO2 molecules is first convert into SO32- by NaOH solution: SO2 + 2OH- › SO32- + H2O Acidification of the solution liberates all SO2: 2SO32- + 2H+ › 2SO2 + 4H2O which is then titrated with 0.0057M iodine solution in which starch is used as end-point indicator: SO2 + I2 + 2H2O › 2HI + H2SO4 Chemicals white wine (carbonated), 1M NaOH, 2M H2SO4, 0.0057M I2, starch solution Apparatus volumetric apparatus, pipette, measuring cylinder, dropper, white tile Procedure 1.> Find out the volume of wine from the label on the bottle. 2.> Pipette 25cm3 of white wine into a conical flask. 3.> Add about 12cm3 of 1M NaOH and stand for about 15 minutes. 4.> Add about 10cm3 of 2M H2SO4 to the mixture and then few drops of starch solution as indicator. Quickly, titrate the mixture with 0.0057M iodine solution. 5.> Record the titre required to produce pale blue colour. 6.> Repeat steps 2-5 for 2-3 times. Data Analysis Trial st 2nd Final reading /cm3 3.05 2.80 26.30 Initial reading /cm3 0.25 9.70 23.25 Volume of I2 added /cm3 2.80 3.10 3.05 Average volume of I2 added /cm3 3.075 Concentration of I2 solution: 0.0057 M
Analysis of Two Brands of Commercial Bleaches
PLK TANG YUK TIEN COLLEGE ADVANVED LEVEL CHEMISTRY (TAS) EXPERIMENT 3 Analysis of Two Brands of Commercial Bleaches Objective To determine the concentration of sodium chlorate(I) (NaClO) in two commercial bleaches and compare the two bleaches on both concentration and price. Procedures . 10.0 cm3 of the bleach "KAO" was pipetted into a clean 250 cm3 volumetric flask. It was made up to the mark using deionized water. 2. 25.0 cm3 of the diluted solution was pipetted into a conical flask. 3. 10 cm3 of 1 M potassium iodide solution and 10 cm3 of dilute sulphuric acid was added into the conical flask also. 4. The mixture in the conical flask was titrated against the 0.0992 M sodium thiosulphate solution. 5. Three drops of freshly prepared starch indicator are added into the conical flask when the reaction mixture turned pale yellow . 6. The mixture was titrated to the end-point. 7. At the end point, the solution turned from dark blue to colourless. 8. Steps (1) to (7) were repeated with another bleach "LION" Results Concentration of standard sodium thiosulphate solution : 0.0992M Brand 1 Trade Name : KAO Bleach Price : $7.33per dm3 ($11/1500mL) Trial 2 Final burette reading / cm3 1.90 23.40 35.00 Initial burette reading / cm3 0.20 1.90 23.40 Volume of Na2S2O3 / cm3 1.70 1.50 1.60 Brand 2 Trade Name : LION Price : $6.67per dm3
Spectroscopy
Chemistry Unit 2 Spectrometry Katie Bennett Spectrum Definition: The several coloured and other rays of which light is composed, separated by the refraction of a prism or other means, and observed or studied either as spread out on a screen, by direct vision, by photography, or otherwise. Introduction to Spectroscopy Spectroscopy is a complex art - but it can be very useful in helping scientists understand how an object like a black hole, neutron star, or active galaxy is producing light, how fast it is moving, and even what elements it is made of. A spectrum is simply a chart or a graph that shows the intensity of light being emitted over a range of energies. Spectra can be produced for any energy of light - from low-energy radio waves to very high-energy gamma-rays. Spectra are complex because each spectrum holds a wide variety of information. For instance, there are many different mechanisms by which an object, like a star, can produce light - or using the technical term for light, electromagnetic radiation. Each of these mechanisms has a characteristic spectrum. . The Electromagnetic Spectrum White light (what we call visible or optical light) can be split up into its constituent colours easily and with a familiar result - the rainbow. All we have to do is use a slit to focus a narrow beam of the light at a prism. This set-up is actually a basic spectrometer.
Deducing the quantity of acid in a solution
Sofia Gaggiotti Chemistry coursework: Deducing the quantity of acid in a solution 20/03/2008 Index Aim and Background information 3 Hazards 3 Protection 4 Method 5 Previous calculations 5 Making the Solution 6 Equipment needed 6 Quantities of materials needed 8 Procedure 8 Making the Titration 9 Equipment needed 10 Procedure 13 References 15 Results and calculations 16 Evaluation 19 Chemistry coursework: Deducing the quantity of acid in a solution Aim and background information The aim of this experiment is to find how to develop and determine an accurate, precise and reliable concentration of an acid rain solution. 1 To do this, we are going to make first a solution of sodium carbonate with distilled water and then a titration in order to calculate the concentration of sulphuric acid in a solution. Solution: a solution is a homogeneous mixture composed of two or more substances. In this mixture, a solute is dissolved in a solvent. Solutions are characterized by interactions between the solvent phase and solute molecules or ions that result in a net decrease in free energy. 2 Titration: a titration is a laboratory technique by which we can determine the concentration of an unknown reagent using another reagent that chemically reacts with the unknown. At the equivalence point (or endpoint) the unknown reagent has been reacted with the known reagent.
Finding the number of Moles of Magnesium and Oxygen in Magnesium Oxide
Finding the number of Moles of Magnesium and Oxygen in Magnesium Oxide Table of Results: SUBSTANCE MASS/g Before After Crucible + lid 39.48 39.48 Crucible + lid + Magnesium 39.61 N/A Magnesium 0.13 N/A Crucible + lid + Magnesium Oxide N/A 39.63 Magnesium Oxide N/A 0.15 Oxygen N/A 0.02 Calculations for Empirical Formula: . Number of moles of Magnesium in Magnesium oxide: Moles/mol = Mass/g ____ Relative atomic mass/ g/mol Moles/mol = __ 0.13g__ = 0.00541 moles ( 3sf) 24g/mol 2. Number of moles of Oxygen in Magnesium oxide: Moles/mol = ____Mass/g______ Relative atomic mass/ g/mol Moles/mol = ___0.02g__ = 0.00125 moles ( 3sf) 16 g/mol 3. Put into ratio: Mg : O 0.00541 : 0.00125 0.00541 = 4.33 0.00125 4.33 : 1 12.99 : 3 13 : 3 Empirical Formula of Magnesium Oxide = Mg O Comparison between calculated empirical formula and literature empirical formula and Sources of Error: The literature empirical formula for Magnesium oxide is MgO meaning the ratio between Magnesium and Oxygen is 1:1. However the results from my experiment differed greatly. Our results ended up in a ratio of 13:3. This could be a result of numerous sources of error and the limitations of the method.
Analysis Of Commercial Vitamin C Tablets
Experiment 5 Date: 18-10-2005 Analysis Of Commercial Vitamin C Tablets Objective To determine the mass of Vitamin C in 1 pill of Vitamin C tablet. Introduction In this experiment, the concentration of sodium thiosulphate solution is not given. So, we need to standardize it through titration. Sodium thiosulphate reacts with iodine in the following reaction: I2 + 2S2O32- ----------------->2I- + S4O62- After an amount of S2O32- is added, the solution of I2 turns pale yellow. When starch solution is added and more S2O32- is added, the solution reaches its end point, which is colorless. In this way, the molarity of the thiosulphate solution is determined. Vitamin C could be oxidized by iodine in the presence of acid in the following equation: Due to the low solubility of iodine, direct titration of iodine solution and Vitamin C is unsuitable. Then how could the experiment be done? The experiment could be done by adding acidified Vitamin C solution into potassium iodide solution. Then, we add potassium iodate to allow the following reaction to take place: IO3- + 5I- + 6H+ ----------------> 3I2 + 3H2O I2 formed in this reaction could react with the Vitamin C in as mentioned in the above equation. The I2 not yet reacted would then be titrated against thiosulphate solution, like the first equation, to determine its amount. This method is a kind of back titration. It is
