the freezing point of cyclohexane we needed a test tube holder‚ 400 mL beaker‚ 600 mL beaker‚ large test tube‚ salt‚ water‚ ice‚ rubber stopper‚ stirrer‚ and thermometer. We took exactly 10 mL of cyclohexane using a buret and put it into the test tube. We then weighed out 50g of salt‚ mixed it in 400 mL of water‚ then added ice. Then the thermometer was inserted through the rubber stopper with the stirrer around the base of the thermometer to about halfway into the cyclohexane. The test tube is then
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Ramsay’s previous discoveries of helium and argon are what inadvertently led to the discovery of krypton (Stewart). Around the time of the discovery‚ Ramsay and Travers planned to extract a large volume of argon from the air‚ liquify the argon‚ and use distillation to discover a lighter element that would fit between helium and argon (Stewart). Since the two chemists had little experience with liquid gases‚ they used liquid air to practice the procedure (Stewart). To begin‚ Ramsay and Travers
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in the bond types between the carbons. Objective: 1- To observe the flame of cyclohexane and cyclohexene. 2- To observe the effect of adding sulphuric acid on cyclohexane and cyclohexene. Apparatus Needed: Test tubes and rack‚ watch glass‚ and matches. Chemical Needed: Cyclohexane‚Cyclohexene‚ 1M of sulphuric acid. Procedures: A. Combustion (to be performed under fume hood) 1. 2-3 drops of liquid cyclohexane are dropped onto a watch glass. 2. Fire is set to it. 3. The flame is observed
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liquids‚ but throughout testing if a chemical reaction occurs with your unknown it is necessary to compare its properties to its original stature. Prior to any testing the unknown sample should be purified through some form of distillation to ensure accuracy and precision. Distillation is the process of vaporizing a liquid‚ condensing the vapor‚ and collecting the condensate in another container(2) . The technique is useful in separating liquid components that have different boiling points (impurities)
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preparation should not exceed 10 slides. Roll nos 1-5 6-11 12-17 18-23 Topic for the ppt solutions suspensions colloids Separation techniques a)chromatography b)centrifugation c)crystallisation Separation techniques a)evaporation b)distillation c)fractional distillation a)metals and non metals b) compounds and
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into a beaker filled with solvent. The solvent will then flow through the paper. The solvent chosen depends highly on its polarity as this will be the characteristic that will separate the different substances. Petroleum‚ ether‚ hexanes‚ cyclohexanes and toluene are some examples of solvents with different polarities as well as increasing polarities.
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Chlorophyll clip_image002Outline the role of photosynthesis in transforming light energy to chemical energy (including raw materials needed for this process) Photosynthesis occurs in all green plants and is the beginning of nearly all food chains therefore a source of life to all living organisms. It is the process where plants transform light energy from the sun into chemical energy. By using light energy trapped by chlorophyll (light absorbing pigment)‚ plants combine carbon dioxide and
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Melting point 1. What two effects do impurities have on the melting point of an organic compound? Soluble impurities affect the melting point of a solid in the following manner. a. The presence of an impurity in the molten compound reduces its vapor pressure thus lowering the melting point of the compound. b. Broaden the melting point range. 2. For what tow purpose are melting points routinely used a. To determine the identity of an organic solid. b. To determine the purity of an organic solid
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complexing agents such as crown ethers. Once pure salts have been prepared‚ it is a straightforward task to convert them to the free metal. This can be done by electrolysis of the fused cyanide or by reduction with calcium or sodium followed by fractional distillation. Properties Rubidium is an alkali metal in group IA of the periodic table with atomic number 37‚ an atomic weight of 85.47‚ and a density of 1.53 Mg/m3. Its melting point is 38.9 °C‚ and it boils at 688 °C. Its atomic radius is 0.248 nm
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give the sun and stars their energy. Oxygen under excited conditions is responsible for the bright red and yellow-green colors of the Aurora. A gaseous element‚ oxygen forms 21% of the atmosphere by volume and is obtained by liquefaction and fractional distillation. The atmosphere of Mars contains about 0.15% oxygen. The element and its compounds make up 49.2%‚ by weight‚ of the earth’s crust. About two thirds of the human body and nine tenths of water is oxygen. The physical state of oxygen is a gas
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