sulphuric acid is dibasic
Demonstrating that sulphuric is dibasic: Aim: The aim of my plan is to demonstrate that sulphuric acid is dibasic. Introduction: Acid is a substance that reacts with a base to form a salt and water similarly a base is a substance that reacts with an acid to form a salt and water. "Lewis (a scientist) states that an acid is a compound that accepts a pair of electrons from a base and a base is a molecule or an ion that donates a pair of electrons to an acid. Acids taste sour and are corrosive and bases are slippery". ? Acid + Base › Salt + Water Acid + Metal › Metal Salt + Hydrogen gas Prediction: I predict that sulphuric acid, H2SO4 is dibasic because it forms two hydrogen (H+) ions in an aqueous solution. It is the molecule of sulphuric acid which changes to sulphate ions (SO42-) and hydrogen ions (H+) when dissolved in water. However, hydrochloric acid is monobasic as it only forms one hydrogen (H+) ion in an aqueous solution. To prove this, I am going to carry out two different experiments that involve a titration and collection of a gas. I assume that it should require me half a volume of sulphuric acid to neutralise sodium hydroxide, NaOH than HCl in titration. In the collection of gas, I expect to collect double the volume of gas when metal reacts with H2SO4 than that of produced in the reaction with HCl. Apparatus: Titration Equipment: Quantity: Reason
Rates of Reaction
Rate of Reaction Experiment Introduction: 8C conducted an experiment to investigate the four factors which affect rates of reaction (temperature, concentration, surface area and the addition of a catalyst.) In this case, we examined the impact concentration has on the rate of reaction. We combined three samples of one type of mixture, but of varying concentrations of the solvent. Unfortunately, due to some human error we were unable to complete the experiment but have detected various indicators which supported our hypothesis. Our observations were recorded in a table intended for what would have been our quantitative data. AIM: To investigate the effect of concentration on the rate of reaction HYPOTHESIS: I hypothesize that the rate of reaction would be accelerated by a greater concentration of solutes. When more solute has been added, there are more particles in the same volume to react with one another, as demonstrated in the adjacent diagram. NOTE: A chemical reaction involves the collision between particles. The particles collide to generate a new substance(s). Fewer particles mean less chance of collision. Independent Variable (x): the concentration of one reactant (in this case, the hydrochloric acid.) Dependent Variable (y): the rate of reaction (i.e. the time it takes for the chemical process to be complete.) Controlled Variables: * The volume of the
Rates of reaction
Rates of Reaction Introduction- Rates of reactions are how fast a reaction occurs. The factors that have an impact on the rate of the reaction are temperature, surface area, catalyst and concentrations. Temperature has an impact as when two chemicals react, their molecules have to collide with each other, and by heating the mixture you will be supplying high amounts of energy which will speed up the reaction. This is kinetic theory. Surface area has an impact on rate of the reaction as If one of the reactants is a solid, the surface area of that solid will affect how fast the reaction is, and this is because the two types of molecule can only bump into each other at the liquid solid interface. So the larger the surface area of the solid, the faster the reaction will be. Concentration has an impact as increasing the concentration of the reactants will increase the rate of collisions between the two reactants. This is collision theory. This is because the molecules in the reaction mixture have a range of energy levels. When collisions occur, they do not always result in a reaction. If the two colliding molecules have sufficient energy they will react. Aim: To investigate the effect of surface area on the rates of reaction. Hypothesis: I predict that when the surface area increases the reaction time will increase, this is because when we make pieces of a reactant smaller we
relative atomic mass of lithium
Determination of the Relative Atomic Mass of Lithium To find out the relative atomic mass of lithium I am going to use two methods. In Method 1 I will use the volume of hydrogen produced as lithium reacts with water. In method 2 I will titrate the lithium hydroxide which is the solution formed from my first experiment. METHOD 1 Table of results Mass of Lithium used (g) 0.08 Initial volume of water in measuring cylinder (cm3) 320 Final volume of water in measuring cylinder (cm3) 148 Volume of hydrogen gas produced (cm3) 172 Treatment of results The equation below shows lithium reacting with water in method 1. 2Li(s) + 2H2O(l) 2LiOH(aq) + H2(g) This equation will help me deduce the number of moles used. The following formula can be used to determine the number of moles of hydrogen gas produced. No of moles = volume 24000 No of moles of hydrogen = 172cm3 24000 = 0.00716 moles Looking at the equation it shows that for every 2 moles of lithium reacted, 1 mole of hydrogen is produced. This means the number of moles of hydrogen must be multiplied by 2 in order to find the number of moles of lithium. No of moles of lithium = 0.00716 x 2 = 0.01432 moles = 0.0143 moles (3 significant figures) Now that I have figured out the number of moles of lithium, I can work out the relative atomic mass of lithium by
Paper chromatography
Introduction It is suspected that a rival company producing felt tip pens is stealing ideas for new colour from primary colour, a leading felt tip pen manufacturer. The company requires proof before it starts making allegations and requires you to devise a test to determine whether the colours have been stolen. Somebody on the inside of the rival company has supplied the company with same prototype from the rival company for you to test whether the rival felt tip pen manufacturer is stealing ideas for new colours from the other company. Aim The aim of this coursework is to find if the rival company is stealing the other company's new idea. To determine if they have stolen news ideas for a new felt tip, I well perform to simple tests however effective (paper chromatography and thin layer chromatography). I well reform tests on the prototype and the company's felt tip to see any simulates. Paper chromatography Paper chromatography is one method for testing the purity of compounds and identifying substances. Paper chromatography is a useful technique because it is relatively quick and requires small quantities of material. Paper chromatography is an analytical technique for separating and identifying compounds that are or can be colored, especially pigments. This method has been largely replaced by thin layer chromatography, however it is still a powerful teaching
Analysis of Aspirin tablets
Laboratory report 7 - Analysis of Aspirin Tablets Name: Leung Dik Ka (14) Name of partner: Lee Wai Chi Date: 19/11/2008 Title of the experiment: Analysis of Aspirin Tablets Aims: To analyze the amount of the active ingredient in different commercial brands of aspirin tablets is carried out, to see whether the manufacturers' claims are justified. Introduction Pharmaceutical manufacturers are required by law to state on the packaging the amount of each active ingredient in their products. In this experiment a consumer survey on the amount of the active ingredient (2-ethanoyloxybenzoic acid, or o-acetylsalicylic acid) in different commercial brands of aspirin tablets is carried out, to see whether the manufacturers' claims are justified. 2-ethanoyloxybenzoic acid can readily hydrolyzed, using a known excess of sodium hydroxide, into the sodium salts of two weak acids, ethanoic acid and 2-hydroxybenzoic acid. The excess amount of sodium hydroxide is then estimated by a back titration with standard sulphuric(VI) acid. The equation for the hydrolysis reaction is: CH3CO2C6H4CO2H + 2NaOH(aq) --> CH3CO2Na (aq) + HOC6H4CO2Na (aq) + H2O (l) Phenol red (pH range 6.8-8.4) is most suitable for this titration due to the presence of the salts of two weak acids, though phenolphthalein is also satisfactory for the present purpose. Procedure [Hazard Warning: 1.0M sodium hydroxide
Analysis of commercial vitamin C tablets
Analysis of commercial vitamin C tablets Objective To determine the vitamin C content in commercial vitamin C tablets by titration between vitamin C (ascorbic acid) & iodine solution. Hence, compare this data with the manufacturer's specification. Principle In this analysis, certain amount of iodine solution, which is known in excess, is added to acidified ascorbic acid solution. Brown iodine can be easily reduced by acidified ascorbic acid to form colourless iodide ion: ‹ Equation I The excess iodine is then back titrated by standard sodium thiosulphate solution, by using a burette and starch solution (used as end point indicator) Similarly, iodine can also be decolourized by thiosulphate ion: 2S2O32- + I2 › S4O62- + 2I- ‹ Equation II Any iodine present will react with starch to form a blue-black complex. However, when all available iodine has been reacted, the blue-black complex becomes colourless which signals the end-point. Hence, the mass of ascorbic acid reacted by iodine can be calculated. Chemicals vitamin C tablet(s), NaIO3, 1M NaI solution, 0.5M H2SO4, approximately 0.06M Na2S2O3, freshly prepared starch solution Apparatus electronic balance, beaker, volumetric apparatus, pipette, glass rod, white tile, dropper, measuring cylinder Procedure 1.> Accurately weigh 0.6 to 0.7g sodium iodate, NaIO3 and
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
Analysis of Commercial Vitamin C Tablets
EXPERIMENT ( 1 ) Topic : Analysis of Commercial Vitamin C Tablets Introduction : In this experiment the vitamin C content of commercial tablets is determined titrimetrically and compared with the manufacturers' specifications. Vitamin C is ascorbic acid which is rapidly and quantitatively oxidized by iodine in acid solution according to the following equation : C6H8O6(aq) + I2(aq) --> C6H6O6(aq) + 2 H+(aq) + 2 I-(aq) The standard method for determination of ascorbic acid involves the direct titration of the acidified sample with a standard iodine solution. But the low solubility of iodine makes this procedure less than ideal. The proposed experiment avoids these difficulties by generating in situ a known excess quantity of iodine by the reaction between iodate(V) & iodide : IO3-(aq) + 5 I-(aq) + 6 H+(aq) --> 3 I2(aq) + 3 H2O(l) After reacting with ascorbic acid, the remaining iodine may then be titrated against standard sodium thiosulphate solution. Chemicals : Vitamin C tablets , 0.05 M Na2S2O3 , 0.5 M H2SO4 , 1 M KI , KIO3 , Starch solution (freshly prepared) Procedures : 1. Accurately weigh out 0.6 to 0.7g of potassium iodate(V). Record the mass.. 2. Dissolve this in deionized water and make up to 250 cm3 in a volumetric flask. 3. Use such iodate(V) solution to standardize the given thiosulphate solution as follows : (a) Pipette 25.0 cm3 of
Analysis of Sulphur Dioxide Content in Wine
EXPERIMENT ( 3 ) Topic : Analysis of Sulphur Dioxide Content in Wine Introduction : In the presence of atmospheric oxygen, the alcohol content of wine can be converted to ethanoic acid making the wines sour & unpalatable. Even small amount of air, over a period of time, can adversely affect wines. The problem can be minimized by the introduction of a suitable reductant which will preferentially react with oxygen. One such reductant is sulphur dioxide but because it is toxic & pungent in odour, limits are set on the amount of "free" sulphur dioxide allowed in wine. Most of the preservative present in wine is "fixed" in the form of NaHSO3. Although this can act as a source of sulphur dioxide, the actual amount of free sulphur dioxide is quite low. In this experiment, the amount of total available SO2 in the wine, irrespective of its actual form in the sample is determined. The method involves first the conversion of all SO2 into SO32-. Acidification of the solution then liberates all SO2 : SO32-(aq) + 2 H+(aq) --> SO2(aq) + H2O(l) SO2 is then titrated with iodine solution : SO2(aq) + I2(aq) + 2 H2O(l) --> 2 HI(aq) + H2SO4(aq) Chemicals : White wine (non-sparkling or non-carbonated), 1M NaOH , 2M H2SO4 , 0.005M I2 , KIO3 , Starch solution (freshly prepared) Procedures : 1. Determine, from the label, the volume of wine in a bottle. 2. Using a pipette,
