by Actual yield of synthesised aspirin: 0.347g 0.347/1.196 * 100= 29 Percentage yield: 29% Melting Points Compound Began Melting (°C) Totally Melted (°C) Range (°C) Pure Aspirin 136 1-2 Crude Aspirin 125 130 5 Product from Willow Bark 120 125 5 The documented melting point for pure aspirin is 136°C. An impure compound will exhibit a lower melting point than this‚ which is what was observed in both the willow bark product and the crude aspirin. Pure aspirin has a narrow
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completes the statement or answers the question. ____ 11. The phase change that is the reverse of sublimation is a. deposition c. condensation. b. vaporization. d. melting. ____ 12. The phase change in which a substance changes from a solid to a gas or vapor without changing to a liquid first is a. melting. c. deposition. b. sublimation. d. vaporization. ____ 13. If a solid piece of naphthalene is heated and remains at 80°C until it is completely melted‚ you know that
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amount of heat required to convert a mass of a solid at its melting point into a liquid without an increase in temperature. As difficult as this may sound‚ this experiment can be carried out with minimal equipment. The following equipment was needed‚ a 100mL graduated cylinder‚ a calorimeter‚ a digital thermometer‚ a calculator‚ water‚ and ice cubes. Procedure: The procedure to find the heat of fusion for ice was measured by melting ice cubes in a known volume and temperature of water and carefully
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Lab 6: Organic Compound Analysis Isabella O’Toole CHY 116 Friday 1:15-4:00 Lab Conducted on 4-12-13 and 4-19-13 4-26-13 This lab was conducted in order to determine the chemical composition of an unknown organic acid. A known mass of acid was dissolved into 30mL of either water or methanol (depending on solubility) and titrated with standardized sodium hydroxide. Data from this allowed the molar
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How do different liquids and solids affect the boiling and freezing point of water? Name 02/12/12 ABSTRACT There are many different substances that affect the freezing and boiling points of water. This experiment was designed to test the effects of five liquid and five solid substances/mixtures on the freezing and boiling points of water. It was hypothesized that if we tested five liquid and five solid substances/mixtures then the results would show that the solids would have a greater affect
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determining the identity of the unknown sample are listed in Table 1. Density (g/cm3) Molecular Weight (g/mol) Melting Point (ºC) Polypropylene 0.905 42.08 170 Polyethylene 0.92 28.05 130-145 Polycarbonate 1.2 158 310 Polystyrene 1.05 104 240 Polyvinyl chloride 1.4 62.5 160-172 Table 1 Properties for five known polymers (Callister 737-775) The melting temperature of a polymer is the point at which it transforms from the solid form to a viscous liquid in which there is little molecular order (Callister
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students‚ you can teach them about negative exponents. Then they can explore the half-life of certain radioactive elements‚ or the size of bacteria and viruses. Explore many scientific facts‚ such as the boiling and freezing point of liquids‚ the melting and freezing points of solids‚ and the temperature of planets‚ Have you been to the playground lately? You’ll find many connections between algebra‚ science‚ and the real world in our article entitled | Math and Social Studiesstudents apply
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Physical Lab 15: Chemical and Physical Properties Experiment 1: Physical Properties of Water Data Table 1: Melting Point Data Initial Time Final Time Observations Weigh Boat A 5:37 pm 7:00 pm 10 min- little puddle just started melting. 20 min- puddle under ice is a little bigger. 30 min- ice is melting more and getting a wetter appearance. 40 min- about half way melted. 50min- still slowly melting a bit more than half gone. 60 min- about a quarter of the cube remains. 70 min- a little les than a
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Christina Hang Vanessa Hang Seng Xiong Period 5 December 14‚ 2012 Molecular Mass by Freezing Point Depression Objective: Determine the molecular mass of an unknown substance by finding the change in freezing point of a solvent when the unknown substance is dissolved in it. Qualitative Data: Trials BHT (g) Cetyl –Alcohol (g) Unknown substance (g) Melting Temperature 1 0.48 g 0 0 69.3 2 0.46 g 0.09 g 0 66.9 3 0.49 g 0 0.11 g 53.7 Analysis: 1.) Determine ___ for the solution of cetyl
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virgin polycrystalline silicon which are placed in a quartz crucible along with small quantities of elements called dopants - the most common of which are boron‚ phosphorus‚ arsenic and antimony. The materials are heated to a temperature above the melting point of silicon‚ 1420 degrees Celsius. Once the polycrystalline and dopant combination has been liquefied‚ a single silicon crystal‚ the seed‚ is positioned on top of the melt‚ barely touching the surface. The seed has the same crystal orientation required
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