Application of Hess's Law to determine the enthalpy change of hydration of Magnesium sulphate

? Name: Penguin Chow Cheuk Yan ? ? Class: 6S Class Number: 14 ? ? Date: 04 - 11 - 2002 ? Chemistry Full Report Experiment 5 Title: Application of Hess's Law to determine the enthalpy change of hydration of Magnesium sulphate (VI) Aim: Using Hess's Law to find the enthalpy change of hydration of magnesium sulphate (VI) Theory: Hess's Law can be defined as the heat given off or absorbed by a reaction is independent of the route taken. In this experiment, the enthalpy change of hydration of Magnesium sulphate (VI) cannot be directly measured by calorimetry in the laboratory as hydration is a very slow process. ?H1 = enthalpy change of hydration of MgSO4(S) ?H2 = molar enthalpy change of solution of hydrous MgSO4(S) ?H3 = molar enthalpy change of solution of MgSO4• 7H2O(S) According to Hess's law, the enthalpy of the overall reaction should be equal to the sum of the enthalpies of the two sub-reactions. Thus, this value can be calculated by applying Hess's Law Procedure: A. Determine the enthalpy change of solution of MgSO4(S) . A balance was used to weigh the empty polystyrene foam cup 2. 50 cm3 of deionized water was poured from the measuring cylinder to the polystyrene cup 3. The temperature of the water in the cup was measured using a thermometer 4. 0.025 mole of anhydrous magnesium sulphate (VI) was weighed accurately by the balance and was added into

  • Word count: 754
  • Level: AS and A Level
  • Subject: Science
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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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  • Level: AS and A Level
  • Subject: Science
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Research on mad cow disease and creutzfeldt-jacob disease

Prion Diseases Mad Cow & Mad Human Aamir Shaikh's SNAB AS coursework Unit 3: Paper 01 Visit or Issue Report Word Count: 1, 964 The two topics covered are Bovine Spongiform Encephalopathy (BSE) and Creutzfeldt-Jacob Disease (CJD), with CJD being the main topic. This is aimed at students who are studying A levels and wish to gain further insight into BSE & CJD. This can be used as a handout or a small text booklet that can be supplied/handed out to student during class/lecture Topic 1 Creutzfeldt-Jacob Disease What is CJD? 1 Symptoms and Effects of CJD 1 Causes of CJD 2 Structure of a prion 2 What do prions do? 3 Methods to combat prions 3 Research 4 Topic 2 Bovine Spongiform Encephalopathy What is BSE? 4 Symptoms of BSE 4 Causes 4 Prevention 5 Glossary 6 Bibliography 7 Validity 8 Creutzfeldt-Jakob Disease What is Creutzfeldt-Jakob disease? Creutzfeldt-Jacob disease is a rare yet

  • Word count: 2106
  • Level: AS and A Level
  • Subject: Science
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Given a Batch of Factory Springs, Estimate the Average Spring Constant and Uncertainty of the Batch.

GIVEN A BATCH OF FACTORY SPRINGS, ESTIMATE THE AVERAGE SPRING CONSTANT AND UNCERTAINTY OF THE BATCH. Outline plan I have been given 3 springs to which I will add different weight. Using the value of extension (?x) I will calculate the spring constant. Hooke's Law says that the stretch of a spring from its rest position is linearly proportional to the applied force (stress is proportional to strain). Symbolically, F = k?x Where F stands for the applied force, x is the amount of stretch (found by new length minus original length), and k is a constant that depends on the "stiffness" of the spring, called the spring constant. Trial plan Set up equipment as above. Measure original length of spring. Add weights 0.5N at a time until spring reaches elastic limit. Record extension (?x). Plot these results on a graph and use this information to gain a sensible number and range of values to use in full experiment. Safety Notes Be sure to keep your feet out of the area in which the masses will fall if the spring breaks Be sure to clamp the stand to the lab table, or weight it with several books so that the mass does not pull it off the table. You need to hang enough mass to the end of the spring to get a measurable stretch, but too much force will permanently damage the spring, as it will have exceeded its elastic limit. Wear safety glasses to protect eyes if spring suddenly

  • Word count: 1896
  • Level: AS and A Level
  • Subject: Science
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Organic and Inorganic Fertilisers

Organic and Inorganic Fertilisers A fertiliser is a chemical or natural substance added to soil to increase its fertility. (From The Concise Oxford English Dictionary.) Organic fertilisers are derived from animal or plant remains that decompose on or in the soil, slowly releasing mineral ions. Inorganic fertilisers are manufactured and consist of mineral ions and are usually sprayed onto soil in solution. Fertilisers are needed because in natural ecosystems, decomposition recycles mineral ions whereas with crops the plants are removed at harvest and therefore the minerals are removed and not replaced. All growing crops require nutrients to stimulate photosynthesis and growth throughout the growing season. (Arable Handbook brochure from Kemira Grow-How.) Some of which are more important than others. The major nutrients are nitrogen, phosphate and potassium. The secondary nutrients are calcium, sulphur, magnesium and sodium and the trace elements are manganese, iron, selenium, copper, cobalt, boron, zinc and iodine. (Multi-choice leaflet from Carrs Fertilisers.) Proportions of elements required for healthy plant growth Of the elements required for healthy plant growth, oxygen, carbon and hydrogen account for 96? - 45? carbon, 45% oxygen and 6% hydrogen. Fig 1: - A graph to show proportions of the elements required for healthy plant growth (The Organic Garden Book by

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  • Level: AS and A Level
  • Subject: Science
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Medical research may be carried out on transgenic organisms to obtain information which can improve medical knowledge. For example, oncogene which causes cancer in humans can be inserted into mouse,

THE ROLE OF TRANSGENIC ORGANISMS CAN ONLY BENEFIT HUMANS. A transgenic organism is an organism whose genome has been modified or genetically manipulated by the introduction of a foreign gene. The first transgenic animal was produced in 1982, when a growth hormone from a rat was inserted into a mouse. Since then, genes from different species, including humans, has been introduced into animals, plants and even micro-organisms. (http://nabc.cals.cornell.edu). Genetic engineering provides an alternative to traditional methods of plant and animal breeding because it is a lot faster and efficient. Medical research may be carried out on transgenic organisms to obtain information which can improve medical knowledge. For example, oncogene which causes cancer in humans can be inserted into mouse, forming a transgenic organism called Oncomouse. The mouse develops tumours and is used in cancer research to find possible drugs for the disease (Biological science D. Taylor). Scientists are also finding ways to produce proteins or drugs in transgenic animals. Milk-producing transgenic animals like cows are especially useful for pharmaceutical medicines. Transgenic animals like pigs may also be designed for organ production, helping to reduce the shortage of kidneys and livers available for transplants. Genetic engineering can help to increase crop yield by developing transgenic organisms

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  • Level: AS and A Level
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Investigating the factors affecting the strength of an electromagnet.

Electromagnet Investigation Introduction I will be investigating the factors affecting the strength of an electromagnet. An electromagnet produces a magnetic field around the wire, it is made by passing current through a coil of wire. The strength of the field is affected by: * Number of coils * Increased current * Softer Iron core I will see if the electromagnet is more powerful when the current is increased. I will keep all of the factors of the investigation the same, to make it a fair test, this includes the same amount of coils and supply voltage. Apparatus The apparatus that I will require are: * A 2v Power Supply * An Ammeter * A Variable resistor * An Iron Bar * Wires * Crocodile clips * 100 Paper clips Method To carry out the investigation, I will first collect all apparatus and set up the circuit (as shown below). Then I will start with OA and eventually increase to 3A by altering the resistance. The current at which I will record the number of paper clips will be every 0.5 of an amp (e.g. 0 , 0.5 , 1 , 1.5 , 2 , 2.5 , 3). To make the experiment more precise and reliable, I will repeat the investigation so I have 2 results for every 0.5 of an amp, I will then make an average number. Prediction I predict that when the current is increased, the electromagnet will become more powerful, and therefore will hold more paper clips on it. To support my

  • Word count: 637
  • Level: AS and A Level
  • Subject: Science
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How the angle of a solar cell affects its output.

How the angle of a solar cell affects its output Introduction: The aim of the experiment is to investigate the relationship between the angles of a solar cell from its light source to the output of the solar cell. I will be able to see how the relationship changes (if there is a change) by the results which I record. Apparatus: The equipment which I will require to carry out my experiment are: A solar cell A multimeter A light source These are the things which I will need to carry out the experiment but I will also need equipment make sure the experiment is accurate, these are: A clamp side with clamp, a piece of wood and blue tack, this will act as a stand on which my solar cell will be placed. The clamp stand and clamp will hold the piece of flat wood in a fixed position, to which the solar cell will be blue tacked into position, this will keep the cell firm and steady. A ruler will also be used to measure the distance of the solar cell from the light source. And a protractor will be used to measure the angle at which the solar cell is placed Diagram Safety In order to carry out this experiment in a safe way I will have to consider a few safety issues. I will have to be careful while working around the light. Because once the light has been switched on and left of a period of time the filament within the light bulb will start to heat up (because of the

  • Word count: 1321
  • Level: AS and A Level
  • Subject: Science
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The Impact of genetic fingerprinting and gene profiling in Forensic Science

Helen Douglas 12.4 BIOLOGY COURSEWORK: The Impact of genetic fingerprinting and gene profiling in Forensic Science Gene profiling and genetic fingerprinting was unheard of in Forensic Science 20 years ago. DNA testing was initially introduced in the 1980s and the first court case, which saw a man put behind bars due to the forensic evidence was in 1985. Following the success of the use of physical proof, numerous cases around the world from paternity tests to identification of American soldiers from the Vietnam War have been solved. A person's DNA (de-oxyribonucleic acid) can be found from a single strand of hair, skin under a murder victim's nails or bodily fluids such as sweat, saliva, semen and blood. The chances of a sample of DNA being the same as another person, other than monozygotic twins is 1 in 24 million. This is why recent cases such as that of Sarah Payne rely so much on DNA samples found at the crime scene. In this case a single strand of Sarah's hair was found on Roy Whitting's sweatshirt and matching fibres from his sweatshirt were found on her shoe, although there was slight controversy as to whether the evidence was contaminated. The method for extracting the DNA from a sample is a complex one. The technique was first developed in this country in 1985, the year of the first proven case. Firstly the DNA must be extracted from the sample of body tissue

  • Word count: 1105
  • Level: AS and A Level
  • Subject: Science
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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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