Titration Lab Report

CHEMISTRY LAB Titration Curves of Strong and Weak Acids and Bases Processing the Data: Questions: . Examine the time data for each of the Trials 1-4. In which trial(s) did the indicator change color at about the same time as the large increase in pH occurred at the equivalence point? In which trial(s) was there a significant difference in these two times? In all the 4 trials, the time taken for color change and the time taken for a large increase in pH was the same, leaving no significant difference between the two values. 2. Phenolphthalein changes from clear to red at a pH value of about 9. According to your results, with which combination(s) of strong or weak acids and bases can phenolphthalein be used to determine the equivalence point? The combination of a Strong Acid and Base will give us the equivalence point: there will be a color change of phenolphthalein at pH 9. It is also observed that the reaction between a Weak Acid and Strong Base can be used to obtain a pH of 9. 3. On each of the four printed graphs, draw a horizontal line from a pH value of 9 on the vertical axis to its intersection with the titration curve. In which trial(s) does this line intersect the nearly vertical region of the curve? In which trial(s) does this line miss the nearly vertical region of the curve? For Trials 1 and 3, the horizontal line from pH 9 intersects the S curve. For

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paper cones investigation

Investigation Report Aim Theory When an object is dropped in air, it accelerates. If it is allowed to drop far enough then it can reach its terminal velocity. This is the maximum velocity of the object during its fall and occurs when the upward force of air resistance acting on the object equals the weight of the object. So at terminal velocity... (P.31, Complete Physics, 1999, Pople, Oxford University Press, ISBN 0-19-914734-5) (P.33, Physics 1, 2000, Cambridge University Press, ISBN 0-521-78718-1) Looking for a formula for air resistance... F = force of air resistance ? = density of air = 1.2kgm-3 c = coefficient of drag for the object / dimensionless A = cross-sectional area of object hitting the air / m2 v = velocity of the object / ms-1 (http://damonrinard.com/aero/formulas.htm) Looking for a formula for the weight of an object... W = m.g W = weight / N m = mass / kg g = acceleration due to gravity, 9.81Nkg-1 (P.55, Physics, 1991, Robert Hutchings, Nelson, ISBN 0-17-438510-2) So putting these formulae together... From the Physics AS course, v = velocity x = displacement t = time so References to the specification Forces and Motion 2821 Forces, Fields and Energy 2824 Aim of your investigation The aim of this work is to investigate the relationship between the time taken for a paper cone to fall and the mass of the cone. Variables

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Catapult Investigation

Mark Cranshaw 0P/11P Physics coursework Catapult Investigation Planning: * Preliminary work The preliminary part of my catapult investigation was to see how far I could stretch an elastic band without breaking and also to test to see what readings I could use in the final experiment. I am going to plan an experiment where I shall investigate the firing distances of 100g weights fired by two elastic bands wrapped around a stool. First of all we did our preliminary experiment. In this we investigated elastic bands to see which would be most suitable to use in our final experiment. We tested the elastic bands with different forces (1-10 Newton's) and recorded the distances of which they were stretched. I realised that if I stretched the elastic bands with more than a force of 10 Newton's then they would probably break or loose their elastic energy. Here is a diagram showing our trial experiment: The results of this experiment are shown on the graph on the next page and also below: Force (Newton's) Distance stretched (cm) 24 2 29 3 36 4 44 5 54 6 64 7 73 8 80 9 86 0 90 1 05 2 09 3 20 4 23 5 25 From the results it is quite easy to see that the bigger the force on the elastic band the further it will stretch. From this I will make a prediction: "The more force put on the elastic band the further the weight will travel the further the elastic

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Explain how twin and adoption studies attempt to distinguish genetic and environmental factors underlying the onset of schizophrenia within families. Review the studies and discuss two limitations of this.

Psychology Essay Explain how twin and adoption studies attempt to distinguish genetic and environmental factors underlying the onset of schizophrenia within families. Review the studies and discuss two limitations of this. Schizophrenia is the label applied to a group of disorders characterised by severe personality disorganisation, distortion of reality, and an inability to function in daily life. Symptoms are mainly disturbances of thought processes, but also extend to disturbances of emotion and behaviour. There are two symptom categories - acute schizophrenia characterised by positive symptoms, such as hallucinations and delusions; and chronic schizophrenia, characterised by negative symptoms such as apathy and withdrawal. However, DSM-IV has now moved away from these definitions and classified schizophrenia into three main sub-types: paranoid, disorganised and catatonic. Understanding Schizophrenia More research has, probably, been devoted to trying to understand the nature of schizophrenia than any other mental disorder. Somatogenic approaches have focused on the role of genetic mechanisms influencing the propensity to develop schizophrenia, while psychogenic approaches emphasise the effect of adverse childhood experiences, particularly abnormalities in family interaction in the aetiology of the disorder. Twin studies Twin studies offer a

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The advantages and limitations of electron microscopy.

The advantages and limitations of electron microscopy There are two main branches of microscopy that are pertinent to cell biology. These branches arise from the two types of microscope; the light microscope and the electron microscope. The basic principles of light microscopy have been known since circa 17th century, however improvements in lens manufacture in circa 19th century allowed the use of microscopy to be much more practically available and useful. This is increased ability inspired rapid research into both the design of microscopes and the preparation of specimens. However, the light microscope can only magnify objects bigger than 0.2 micrometres; due to its limited resolving powers. This is because it utilises a beam of light. Relatively, light has a long wavelength, this means that when there are two small points close together there is too much refraction and wave front overlap, the eye then only sees one point. This can also be considered in terms of objects "crossing the path" of the wavelength. The smallest wavelength of visible light is 400nm, the diameter of mitochondria is 1000nm, and therefore mitochondria cross the path of the light wave. However ribosomes have a diameter of 22nm, and do not cross the path of the light wave and are therefore not seen by the light microscope. As biologists came to realise these limitations they understood that the

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investigating the relationship between the diameter and the current in a wire at its melting point

Investigation Report Aim Theory Electrical resistance is a measure of the degree to which an object opposes the passage of an electric current. The SI unit of electrical resistance is the ohm. Its reciprocal quantity is electrical conductance measured in siemens. Resistance is the property of any object or substance of resisting or opposing the flow of an electrical current. The quantity of resistance in an electric circuit determines the amount of current flowing in the circuit for any given voltage applied to the circuit. Some formulae for resistance are where R is the resistance of the object / ? V is the potential difference across the object / V I is the current passing through the object / A (Ref. http://en.wikipedia.org/wiki/Electrical_resistance) where R is the resistance/ ? ? is the resistivity / ?m l is the length of the wire / m A is the cross section area of the wire / m A = ?() = ? where A is area / m d is the diameter / m Putting the formulae together, so (Ref. http://physics.bu.edu/~duffy/PY106/Resistance.html) Aim of investigation The aim of this work is to investigate the relationship between the resistance and the diameter of the wire. Variables Variable Independent / Controlled / Dependent Resistance D Resistivity C Length of wire C Diameter I Prediction Since the theory suggests that So So the resistance should be

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Preparation of a Haloalkane

Experiment 2 Preparation of a Haloalkane Date: 11-9-2006 Objective To produce 2-chloro-2-methylpropane from 2-methylpropan-2-ol. To find the yield of 2-chloro-2-methylpropane. Introduction 2-chloro-2-methylpropane is formed when 2-methylpropan-2-ol and concentrated hydrochloric acid are added together. Because alcohols undergo substitution rapidly, the reaction takes place at room temperature. Afterwards, the haloalkane would be separated with a separating funnel, dried with anhydrous sodium sulphate and extracted by distillation. Procedure . About 9 ml of 2-methylpropan-2-ol was poured into a measuring cylinder and the measuring cylinder was weighed. 2. The 2-methylpropan-2-ol was poured into a 50ml separating funnel. The mass of the empty measuring cylinder was weighed again. 3. About 20ml of concentrated hydrochloric acid was added into the separating funnel, 3ml at a time. This procedure was carried out by the window side. 4. After each addition, the funnel was sealed and was shaken. The tap was opened at intervals to allow the gas produced to be released. 5. The separating funnel was allowed to stand near the window for 20 minutes. 6. A distillation apparatus was set up, as in the diagram below. 7. The small flask in the above set-up was weighed. 8. The lower aqueous layer in the separating funnel was discarded into a beaker. 9. Excess

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Cystic Fibrosis

Cystic Fibrosis Cystic Fibrosis (CF) is an inherited disease caused by a mutation in a gene responsible for producing a protein called "cystic fibrosis transmembrane regulator" (CFTR). Most people have 2 genes which produce this protein, but only one is needed to prevent the disease. This means that CF is "autosomal recessive", meaning that a person with the disease has a mutation in both CFTR (one mutated gene from each parent). Someone with one mutated gene and one normal gene is a carrier. Carriers do not show the symptoms of CF, as they have one working gene, but they may pass a copy of the defective gene onto their children. The CFTR gene is responsible for producing the CFTR protein, which allows Cl- ions to diffuse out of cells in water regulation. If the gene in the DNA is mutated, the mRNA produced in transcription will code for the wrong sequence of amino acids, so the protein made by the mRNA in translation will be the wrong shape, and therefore will not function correctly. This diagram shows the normal situation, where there is too much water in the mucus (outside the apical end of the cell). The sodium pump moves Na+ ions out of the cell, into the tissue fluid outside the basal end of the cell. The Na+ channel allows sodium ions to diffuse into the cell to replace those lost, causing a more negative water potential in the cell, so water moves out of the mucus

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Test of the reed switch capacitors in series and in parallel

School: Class Number: Name: Class: Date: 1th May, 2008 Mark: Title Test of the reed switch - capacitors in series and in parallel Objective - To use a reed switch to measure the capacitance of some real capacitors, including those of series and parallel combinations - To investigate how the reed switch current varies with the frequency Apparatus Reed switch x1 Signal generator x1 Resistance substitution box x1 Battery box with 4 cells x1 Milliammeter x1 Voltmeter x1 Capacitors C1 and C2 Connecting wires Theory Reed switch current In the experiment, the reed switch allows the capacitor to be charged up and discharged rapidly. If a capacitor with capacitance C is charged up at a voltage V, the charge Q stored in it will be equal to CV. If the frequency f is operated by the reed switch, the charging up and discharging process will be repeated f times per second, the charge Q in the capacitor will be delivered to the milliammeter at the same rate. Assuming the capacitor is fully charged and discharged every time, the total charge Q total passing through the milliammeter per second is equal CVf, which is the theoretical current I. And the capacitance of the capacitor can be estimated by the formula C = I/ Vf. Capacitors in parallel If capacitors C1, C2, ..., CN are connected in parallel, the charges stored in each capacitor are shown as

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Experiment to determine the ethanol content of wine

Experiment to Determine Ethanol Content of Wine The purpose of this experiment is to determine the ethanol content of each of the wines and compare the value determined to the value quoted on the label. These results can then be used to conclude which region is more accurate in quoting the value of the ethanol content of the wine. This experiment takes advantage of the fact that ethanol is less dense than water in solution. The density of ethanol at 20°C is 0.789 g/cm3 while the density of water at the same temperature is 0.998 g/cm3. It then follows that different solutions of ethanol and water will have different densities also, because the relative volume of ethanol increases and water decreases so the density of higher percentage ethanol solutions will be less than the density of lower percentage ethanol solutions. This occurs because water molecules are much smaller than ethanol molecule, meaning more water molecules can "pack" into a smaller volume than ethanol molecules, meaning there is more mass per unit volume of water compared to ethanol, meaning it has a higher density. In this experiment, solutions of ethanol in water were made up, going from 0% to 20%. These were then weighed, and the density of the ethanol was calculated. From this, a graph of percentage ethanol solution against density was made. This graphs later compared to the density of the wine, so

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