Determination of isoelectric point of protein (casein).
Determination of isoelectric point of protein (casein). Introduction: Casein is a globular colloidal protein. Globular proteins are hydrophobic proteins which in certain external condition are soluble in eater. The ph at which the protein is electrically neutral is known as the isoelectric point. A globular protein such as a casein becomes increasingly insoluble as it approaches its isoelectric point. Objectives The object of this experiment is to determine the isoelectric point of casein (protein), which can be precipitated from the solution. Apparatus 9 test tubes pipettes - 1ml - 5ml - 10ml colorimeter Materials Distilled water Acetic acid - 0.01 M - 0.1M - 1.0 M casein - 0.5g/1 in 0.1 M sodium acetate Method . The calorimeter is switched ON to allow it to "warm up". 2. In order to distinguish between the different acidity levels contained in each test tube, the 9 test tubes were labelled from 1-9. This is important because all solution are a similar colour. 3. Following the designated volumes required on table 1, the volumes of distilled water was then pipetted into each test tube. The acetic acid was then pipetted into each test tube according to the values in the table 1. 4. In order to reduce the chances of contamination , the designated amounts of 0.01M acetic acid was pipetted first to test tubes 1 and 2 because the 0.01 M acetic acid is
Identification of amino acids by using paper chromatography
Identification of amino acids by using paper chromatography Aim To separation and identification of amino acids by using paper chromatography Introduction Chromatography is a techniques separation of mixtures It involves passing the sample, a mixture which contains the analyte, in the "mobile phase", often in a stream of solvent, through the "stationary phase." The stationary phase retards the passage of the components of the sample. When components pass through the system at different rates they become separated in time, like runners in a mass-start foot race. Each component has a characteristic time of passage through the system, called a "retention time." Chromatographic separation is achieved when the retention time of the analyte differs from that of other components mixtures in the sample. There are many types chromatography but there are four main types which are Liquid Chromatography Liquid Chromatography this is used in the world to test water samples to look for pollution in lakes and rivers. It is used to analyze metal ions and organic compounds in solutions. Liquid chromatography uses liquids which may incorporate hydrophilic, insoluble molecules also Gas Chromatography Gas Chromatography is used in airports to detect bombs and is used is forensics in many different ways. It is used to analyze fibres on a persons body and also analyze blood found at
Aim: To determine the conecentrations of hychloric acid and ethanoic acis by thermometric titration and find the enthalpy of neutralization.
Experiment 12 ~ A thermometric titration ~ Lab Report Shek Pok Man, Dominic (6B 24) Aim: To determine the conecentrations of hychloric acid and ethanoic acis by thermometric titration and find the enthalpy of neutralization. Procedure: (I) Titration of HCL with standard NaOH: . 50cm3 of NaOH solution is pipetted and transfer to the polystyrene cup, It was allow to stand for a few minutes. 2. The initial temperature was recorded. 5.0 cm3 ofHCL was burette to the cup. 3. The mixture was stirred well by using the thermometer, the temperature was recorded. 4. Sucessive 5.0 cm3 portions of HCL was added and the mixture was stirred, the temperature was recorded after each addition. 5. The adding and recording process was continued till the addition of 50 cm3 of acid. (II) Titration of CH3COOH with standard NaOH: . The procedure was the same as HCL except CH3COOH was used. Results and Calculations: (I) Titration of HCL Volume Added/ cm3 .0 5.0 0.0 5.0 20.0 25.0 30.0 35.0 40.0 45.0 50.0 Temp /oC 25.0 27.5 28.5 30.0 30.5 31.0 30.0 29.0 28.5 27.5 22.5 (II) Titration of CH3COOH Volume Added/ cm3 0.0 5.0 0.0 5.0 20.0 25.0 30.0 35.0 40.0 45.0 50.0 Temp /oC 23.0 24.5 24.5 24.5 24.5 24.5 24.5 24.5 24.5 24.0 24.0 Calculations: 3. Concentration of HCl: (1)(50) = m (25) m = 2M
The argument that refugees have a negative effect on society has been a topic of great debate for many years, both in the UK and across many other countries.
The argument that refugees have a negative effect on society has been a topic of great debate for many years, both in the UK and across many other
Titration. As the purpose of the titration is to determine the concentration of potassium hydroxide solution, in order to analyse this unknown solution, we must have a standard solution (hydrochloric acid) to react with the unknown solution.
ACCESS CHEMISTRY UNIT A Practical Assignment - Titration Introduction Titration is a laboratory method of determining the concentration of a known reactant and is also known as volumetric analysis. Two solutions are involved. One solution is measured and poured into a flask, whilst the other is poured into a burette and added drop by drop until the required reaction is completed. The purpose of titrations is usually to determine the concentration of an unknown solution whilst knowing the chemical equation for the reaction by using a known concentration of a second solution. Titrations can also be used to determine the equation for a reaction whilst the concentrations of both solutions are known. A PH indicator is usually used to determine the endpoint of the reaction, although not all reactions require an indicator as the colour change occurs in the reaction between the two solutions. As the purpose of the titration is to determine the concentration of potassium hydroxide solution, in order to analyse this unknown solution, we must have a standard solution (hydrochloric acid) to react with the unknown solution. The standard solution is one in which the concentration is known. Aim: The aim of this experiment was to determine the concentration of the potassium hydroxide solution which was unknown using another solution (concentration known) of hydrochloric acid.
Objective : To determine the concentration of an unknown diprotic acid using acid-base titration.
Objective : To determine the concentration of an unknown diprotic acid using acid-base titration. Introduction : Volumetric analysis is a quantitative method of chemical analysis. A solution of accurately known concentration is reacted with a solution of the substance whose concentration desired. By comparing the reacting volumes, the concentration of the unknown can be determined. The actual procedure of adding one solution to the other for a complete reaction is called a titration. The two types of titrations are acid-base titrations and redox titrations. In this experiment, the molar mass of a diprotic acid is measured by acid-base titration. This method exploits the BrØnsted-Lowry acid-base theory. In this model, any acid is defined as a proton(hydrogen ion, H+) donor, and a base is defined as a proton acceptor. When an acid and base react, protons are transferred from the acid to the base. HA + B-› A- + HB The resulting solution is neutral, it has neither acid nor basic properties. The point at which the reaction is complete is referred to as the equivalence point, reactants are in stoichiometric proportions, this is often not visible, as acids and bases are colourless and so an indicator is required. Since the products of an acid-base reaction may be acidic, basic or neutral, it is important to choose an indicator so that the end point matches the equivalence
I am for the reduction of sulphur dioxide and nitrogen oxide emissions by 80% by the year 2010. We need to take drastic action because the effects on us all are very serious. We must protect ourselves and safeguard our future.
Geography Coursework I am for the reduction of sulphur dioxide and nitrogen oxide emissions by 80% by the year 2010. We need to take drastic action because the effects on us all are very serious. We must protect ourselves and safeguard our future. Introduction Acid rain is a very serious topic in our environment today. It is a problem that each and every person contributes to. Acid pollution is not only eating away at our forests and vegetation, but it is also destroying the entire ecosystem. But, whenever the discussion comes up about cleaning up the damage of acid rain and the possible solutions, people just point the blame at others so they won't have to pay more than their share of the cost. Well, many people can talk the talk about being environmentally safe, but they can't walk the walk when it comes to do something about it. Efforts are probably being made to stop acid pollution, but the public isn't notified about it. Acid rain is damaging everything it comes in contact with, from tiny organisms to the tallest buildings. Although media attention has shifted towards other environmental issues such as global warming, acid rain continues to be a major problem at the beginning of the 21st century. It must be dealt with, or the consequences will be disastrous. What is acid rain? Rain is naturally slightly acidic (around pH 5) because it contains carbon dioxide. If it
Structure and biological significance of lipids.
Scott Bissett L6Du Structure and biological significance of lipids Lipids are made up of a wide variety of molecules, but they all contain carbon, hydrogen and oxygen, with a much higher percentage of carbon and hydrogen molecules than oxygen. There are three kinds of lipids in living organisms: triglycerides, phospholipids and steroids (hormones). Triglycerides are made up of a glycerol molecule, with three fatty acid chains attached by ester linkages. Glycerol is an alcohol containing 3 carbon atoms. The fact it is an alcohol means it has an -OH group at one end. Fatty acids are hydrocarbon chains, with a -COOH group at one end. This -COOH group reacts with the -OH group of glycerol, and a condensation reaction occurs, which is what forms the ester linkage. As this breaks apart the -COOH group, which is what makes fatty acids acidic, once the condensation reaction has occurred, the fatty acids will no longer have any acidic properties. As the triglyceride is effectively surrounded by hydrocarbons, it is hydrophobic (water-hating) There are two types of fatty acids: saturated and unsaturated. Saturated fatty acids have no double bonds, and so the maximum amount of hydrogen molecules attached. Unsaturated has at least one carbon double bond, and so could potentially have more hydrogen. Monounsaturated fatty acids have just one carbon double bond, whereas polyunsaturated
Does the amount of hydrogen gas formed in the below reaction depend on the amount of magnesium used?
Aim: Does the amount of hydrogen gas formed in the below reaction depend on the amount of magnesium used? Prediction: I predict that as the amount of magnesium used increase, so will the amounts of hydrogen gas produced. I will use the collision theory to explain this. The collision theory involves a chemical reaction taking place between particles when they collide. There are a variety of factors that affect how frequently particles collide, and how successful these collisions are in making a chemical reaction: * Concentration of acid: this is how many molecules are in the acid the higher the concentration the more molecules are in there. When there is a higher concentration the reaction will occur faster because there are more molecules to react with so the reaction takes place more frequently. * Type of acid: different kinds of acids are more or less reactive than others so if you use different types of acids you will get different results. * Surface area of magnesium: as the surface area increases it will also become more reactive because there will be a larger area for the acid to collide with. In this particular experiment, my altering factor will be the length of the magnesium strip; this will be measured in cm. Diagram: Plan: Equipment: * 100ml measuring cylinder * Conical flask * 30cm magnesium ribbon * 100cm3 dilute sulphuric acid * Plastic tub
The aim was to become accustomed to working with the equipment and to find optimum levels of hydrochloric acid and magnesium ribbon to produce 60cm of hydrogen, a sensible amount to produce in the real experiment.
Aim: The aim was to become accustomed to working with the equipment and to find optimum levels of hydrochloric acid and magnesium ribbon to produce 60cm of hydrogen, a sensible amount to produce in the real experiment. We also began to investigate the effect of temperature on the rate and the result of the product (hydrogen). It also served to discover any errors in the procedure which could affect the final result and prevent us getting accurate results, thus allowing us to eliminate these errors in the real experiment. Diagram: Method: We attached a gas syringe via a plastic tube to a test tube and used a clamp and stand to hold the gas syringe in place. Having poured 25cm of hydrochloric acid (of strength 1M) into the test tube, we placed a strip of magnesium ribbon (which length varied each time we repeated the procedure) in the test tube and rapidly pushed a rubber bung into the top of the test tube to avoid any gas (hydrogen) produced in the reaction escaping. We then poured out the contents of the test tube and repeated the procedure using the same amount of hydrochloric acid but a different length of magnesium ribbon. The next procedure we carried out involved changing another variable. Having discovered what length of magnesium ribbon would produce 60cm of hydrogen when allowed to react with 25cm of hydrochloric acid, we then used this length of magnesium
