Analysing the vitamin C content in different fruit juices

Title : The Vitamin C Content in Fruit Juices Name : Yii Seng Ong Date : 28 August 2011 Class : 12M15 Student ID : 2011200378 Name of lecturer : Madam Ida Muryany binti Md. Yasin Objective . To determine and compare the concentration of vitamin C in different kind of fruit juices 2. To determine and compare the concentration of vitamin C in freshly prepared fruit juices and carton fruit juices Introduction . Vitamin C Vitamin C or also can be known as ascorbic acid is the elonic form of 3-oxo-L-gulofuranolactone. It can be synthesized from glucose or extracted from other plant sources such as blackcurrants, rose hips or citrus fruits. The empirical formula for vitamin C is C6H8O6. Other than that, the molecular weight for ascorbic acid is 176.1. Its melting point is about 190°C( with decomposition). The appearance is white to slightly yellowish crystalline powder. It is practically odourless, with a strong acidic property and a sour taste. Figure 1 : 2D structure of vitamin C Figure 2 : 3D structure of vitamin C Generally, vitamins are a group of complex organic compounds which play an essential role in animal metabolic process but which the animal cannot synthesis. Vitamins do not provide energy however, in their absence the animal develops certain deficiency diseases or other

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Write an account of buffer solutions.

F7 Essay Writing (Buffer Solution) Q. Write an account of buffer solutions. Guidelines: In your answer you should consider, giving examples, (a) definition (b) their compositions --- weak acid and its salt (acidic buffer), e.g. CH3COOH / CH3COONa --- weak base and its salt (basic buffer), e.g. NH3 / NH4Cl (c) how they work --- equilibrium shift after addition of a small amount of strong acid / strong base to buffer, --- resistance to pH change upon addition of small amount of acid / base (d) their applications --- for checking indicator solution and calibrating pH meters --- for controlling solution pH for chemical / biochemical reactions, --- for preserving food (e) their importance in nature --- maintenance of blood pH __________________________________________________________________________ ~ Sample Essay ~ A buffer solution is one which resists changes in pH when small amounts of acid or alkali is added to it. It plays an important role in chemical processes where it is essential that a fairly constant pH is maintained. Buffer solutions could be classified into two types, namely acidic buffer and basic buffer solutions. Acidic buffer solutions An acidic buffer solution is one which has a pH less than 7. They are commonly made from a weak acid and its sodium salt. A mixture of ethanoic acid and sodium ethanoate solutions is a typical example.

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Biology coursework planning - the effect of lead chloride on the growth of cress seeds

Biology coursework planning - the effect of lead chloride on the growth of cress seeds Aim: To investigate the effect of different concentrations of a heavy metal chloride, namely lead chloride, on the growth of cress seeds. Introduction: Heavy metals compounds, such as lead chloride are able to dissolve in rain and enter the soils surrounding plants. Some sources of such compounds are exhaust fumes from vehicles, additives in gasoline and paints, fertilisers and mining. Lead chloride is able to accumulate in the soil at sufficient concentrations and is easily absorbed by plants. For plants, lead is a toxin and when present in significant amounts, can cause severe decreases in their growth as well as death. The toxicity of heavy metals is seen as the irregularities in the normal functioning of the plant rather than direct toxicity to plant cells. Symptoms include stunted growth and the yellowing of plants (called chlorosis). Heavy metals collect in different organs of a plant and produce variable effects. Lead disrupts the plant's plasma membrane structure as well as permeability (proteins in the membrane), osmotic balance (the intake of water and ions) and indirectly, plant metabolism (the availability of nutrients for chemical reactions.) These factors are discussed below in further detail. The root cells of a plant carry proteins called chelates in their cell

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Heat of Neutralization. Objective: To investigate the enthalpy changes () of various acid-base neutralizations.

Title: Heat of Neutralization Objective: To investigate the enthalpy changes () of various acid-base neutralizations. Chemicals and Apparatus: .0M hydrochloric acid, ~1.0M sodium hydroxide solution, one thermometer, one polystyrene foam cup with lid, two pieces of 50.00 burette, two filter funnels, one piece of 25.00 pipette, pipette filler and a 100 beaker. Background: All chemical reactions involve energy changes. The study of energy changes is an important part of chemistry. Fundamental to the thermo-chemistry is the law of conservation of energy, which states that energy is neither created nor destroyed, but can be converted from one form to another. An exothermic reaction is one in which stored chemical energy is converted to heat energy (heat is released to the surroundings), conversely an endothermic reaction is one in which heat energy is converted to chemical energy (heat is absorbed into the system). The enthalpy (H) of a substance, sometimes called its heat content, is an indication of its total energy content. The equation for calculating the enthalpy change (heat change) is given by ?H = -m x c x ?T where m is the mass of the sample, c is the specific heat capacity of the sample and ?T is the change in temperature. The sign for ?H indicates the direction of heat flow, positive for endothermic processes and negative for exothermic processes. In this

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Investigating respiration of maggots

Investigating respiration of maggots By Osman Khan Lee 13 Aim The aim of my investigation is to see how the rate of respiration of some maggots differs between room temperature and other temperatures, in terms of volume of oxygen produced. Simple Prediction I predict that as I raise the temperature of the maggots, the rate of respiration will increase. I think this because respiration is an enzyme-dependant process of reactions. Increasing the temperature will give the enzymes and substrates more kinetic energy and therefore will increase the rate of respiration. This is explained in further detail later on. Method . Using a syringe filled with manometer fluid, I will half fill a manometer. 2. I will then attach a 3-way tap to one of the delivery tubes on the bung and to this tap I will attach a syringe. 3. Next I will put 2g of soda lime in the bottom of each of the two boiling tubes, and will then place a gauze into each, which will rest slightly above the soda lime. 4. I shall then weigh some maggots using some measuring scales, and then put these into one of the boiling tubes, ensuring that none come into contact with the soda lime. After doing this I will place another gauze on top of the maggots to prevent them climbing up the tube. 5. I will then connect this boiling tube up with the manometer, as shown in the diagram. 6. I will then putt some glass beads

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Fighter Pilot A Statistical Analysis of Reaction time and its Correlation with Dominant & Non-Dominant Hands

Fighter Pilot A Statistical Analysis of Reaction time and its Correlation with Dominant & Non-Dominant Hands Introduction This experiment seeks to determine reaction times in two groups of matched subjects; dominant and non-dominant hands, using the ruler drop test. Reaction time experiments are performed to measure the alertness of the mind and will give an indication of the speed of the reflexes that different groups of varied individuals have. The experiment tests how long it takes the brain to translate visual information into the voluntary motor commands, actions which lead to a ruler being grabbed. The shorter the length at which the ruler is grabbed, the shorter time and therefore the faster the person's reaction. The controls of these processes within the human body are the responsibility of the nervous system which is the seat of voluntary and involuntary movements along with language, emotion and memory. (1) The experiment begins with an environmental stimulus via light reflected from a moving ruler being dropped from a height above the subject's hand. (1) This transmits into a sensory nervous impulse within the optic nerve. Beginning in the retina of the eye, information is detected by photoreceptors (rods and cones) they relay the visual signals on to bipolar cells which transmit on to ganglion cells. (2) The axons of all ganglion cells in the retina of each

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Find out if enzymes work faster or slower at different temperatures.

Nick Spong Biology 10/11/03 Introduction This is the plan and evaluation of an experiment to find out if enzymes work faster or slower at different temperatures. We will be timing how long it takes to see a cross through 20cm3 of Marvel milk solution at three different temperatures. We will be using the enzyme neutrase to break down Marvel milk. Hypothesis My hypothesis (theory) is that at temperatures over 40°c the neutrase will be increasingly denatured and the milk will not clarify. Under 40°c the neutrase will be slowed down. However I predict that at 40°c the neutrase will be working well as this temperature is near its optimum temperature and so the milk will decolorize the fastest. I have made my prediction based on the following evidence: The reason that the milk will decolorize or do anything at all is because neutrase is an enzyme. Enzymes are biological catalysts. This means that they are a biological life form that catalyses (speeds up) a process. They have an optimum temperature and pH. Both of these have to be almost exactly right, otherwise their performance deteriorates rapidly. In high temperatures the enzyme will be denatured and will not work even if you bring the temperature back down. However, at low temperatures, and low and high pH's, all you have to do is bring the environment close to the enzyme's optimum environment and the enzyme

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Ozone chemistry speech. Today, I am here to inform you that an ozone hole has been detected over Antarctica and the concentration of ozone will continue to decrease across the globe if the emission of ODCs, such as CFCs, does not reduce.

ERT ORAL SCRIPT (Year 2004- Channel 7 news, slide 1) Breaking news in LA today is that the new movie premier The Day After Tomorrow is actually based on a true event that happened in 1986 at an international conference on climate change. However, it was not global warming leading into an ice age that was discussed, but (slide 2) the discovery of the ozone hole that biologically dangerous ultraviolet (UV) radiation cannot be completely absorbed to preserve the life forms on Earth. Thankfully, unlike the movie, 24 countries agreed to abide to the Montreal Protocol on substances that deplete the ozone layer, which aimed to gradually phase out all ozone-destroying chemicals, ODCs for short. Although measures have been taken, the ozone layer will not recover until the middle of this century as most ODCs have a lifetime of 20 to 100 years. Here coming up, is an extract from a video of the conference. (Year 1986, slide 3) Ladies and gentlemen, I am Professor Rowland. Today, I am here to inform you that an ozone hole has been detected over Antarctica and the concentration of ozone will continue to decrease across the globe if the emission of ODCs, such as CFCs, does not reduce. USA: The CFCs' industry is worth 8 billion dollars per year. I understand. The chemical is ideal for many purposes as it is used as a solvent and cleaning agent in the electronic industry, a non-toxic

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Measurement of the resistivity of Nichrome

Measurement of the Resistivity of Nichrome (NiCr) Introduction In this coursework, I am going to measure the resistivity of Nichrome. Nichrome is a non-magnetic alloy of nickel and chromium. It is a good conductor of electricity and heat, and has a high melting point. Due to its relatively high resistivity and resistance to oxidation at high temperatures, the wire made of Nichrome is widely used in heating elements, such as in hair dryers, electric ovens and toasters. What does Resistivity mean? Resistivity (also known as electrical resistance) is a measure of how strongly a material opposes the flow of electric current. It is normally static and could be varied by changing the temperature. In general, resistivity of metals increases with temperature, while the resistivity of semiconductors decreases with increasing temperature. High values of resistivity imply that the material making up the wire is very resistant to the flow of electricity. Low values of resistivity imply that the material making up the wire transmits electrical current very easily. The unit of resistivity is the ohm meter (? m). The resistivity ? (rho) of a material is given by > ? is the static resistivity (measured in ohm metres, ?·m); > R is the electrical resistance of a uniform specimen of the material (measured in ohms, ?); > L is the length of the piece of material (measured in

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Reactions of aldehydes and ketones. The purpose of this experiment is to compare some reactions of ethanal and propanone.

Date: 8/11/2011 Exp. No.: 25 Title: Reactions of aldehydes and ketones Aim: The purpose of this experiment is to compare some reactions of ethanal and propanone. Introduction: In this experiment, ethanal and propanone were chosen as they are relatively safe. The structures of the 2 compounds are as follow: Ethanal Propanone In this experiment, we are going to investigate the following reactions of these 2 compounds: . Addition 2. Condensation 3. Oxidation 4. Iodoform reaction Apparatus and chemicals: Apparatus: Safety spectacles, hot water bath, cold water bath, test tubes, beakers Chemicals: Saturated hydrosulphite solution , 2,4-dinitrophenylhydrazine solution, 0.1M potassium dichromate solution, 1M sulphuric acid, Fehling's reagent (Fehling solution A + Fehling solution B), 0.05M Silver nitrate solution, 2M sodium hydroxide solution, 2M ammonia solution, iodine solution 10% (in KI(aq)) Procedures: Part 1: Addition reaction with sodium hydrogensulphite . About 2 cm3 of saturated sodium hydrogensulphite solution was added into a test tube. 2. The test tube was put into a cold water bath. 3. Similar volume of ethanal was added drop by drop into the test tube. 4. The experiment was repeated using propanone instead of ethanal. Part 2: Condensation reaction with 2,3-dinitrophenylhydrazine . About 1 to 2 drops of ethanal was added

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