Constructing Heating/Cooling Curve

2366 WordsMar 14, 201310 Pages
| Chemistry Lab Report | Constructing Heating/Cooling Curve | | Salman Ishaq 12-E | 1/27/2013 | | BACKGROUND As energy flows from a liquid, its temperature drops. The entropy, or random ordering of its particles, also decreases until a specific ordering of the particles results in a phase change to a solid. If energy is being released or absorbed by a substance remaining at the same temperature, this is evidence that a dramatic change in entropy, such as a phase change, is occurring. Because all of the particles of a pure substance are identical, they all freeze at the same temperature, and the temperature will not change until the phase change is complete. If a substance is impure, the impurities will not lose energy in the…show more content…
8. Set up the container for the hot-water bath. Attach two ring clamps, one above the other, to the second ring stand beneath the test tube assembly. Place a wire gauze with ceramic center on the lower ring. Set a third 600 mL beaker, which should be empty, on the gauze and raise the beaker toward the test-tube assembly until it surrounds nearly one-half of the tube’s length. The beaker will pass through the ring clamp without gauze, and the test tube should not touch the bottom or sides of the beaker. The top clamp keeps the beaker from tipping when the beaker is filled with the hot water. PART 2–MELTING A SOLID: QUICK TEST 9. Check the temperature of the water for the hot-water bath. When it is 85°C, turn off the burner or hot plate. If the temperature is already greater than 85°C, shut off the burner or hot plate, and add a few pieces of ice to bring the temperature down to 85°C. Then, using beaker tongs remove the beaker of hot water from the burner. Using tongs or hot mitts carefully pour the water into the empty beaker until the water level is well above the level of the solid inside the test tube. Set the empty beaker on the counter. You will use it again in step 20. 10. Begin timing. The second the water is poured, one member of the lab group should begin timing, while the other reads the initial temperatures of the bath with one thermometer and sample with the other thermometer.
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