| Videos: 20 results |
Centrifuging a Sample John W. Moore, Jerrold J. Jacobsen, Lois M. Browne, John F. Zimmerman
The demonstration on this page shows a technique that should not be used by undergraduate chemistry laboratory. This video shows what happens to sample in a centrifuge while the centrifuge is on, and the result of stopping the centrifuge improperly. A narrative is included in this video: The centrifuging process allows the solvent to completely settle out. The jarring caused by hand braking destroys the distinct separation between supernatant and solid.
Separation Science |
Laboratory Equipment / Apparatus
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Centrifuge
Centrifuging safety considerations, centrifuging a sample, loading and unloading a centrifuge, removing the supernatant, and washing the precipitate are discussed and demonstrated.
Laboratory Equipment / Apparatus |
Separation Science
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Extraction
Use of a separatory funnel to carry out extraction is demonstrated.
Laboratory Equipment / Apparatus |
Separation Science
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Filtration
Gravity and vacuum filtration are demonstrated.
Laboratory Equipment / Apparatus |
Separation Science
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Recrystallization
Recrystallization procedures using a single solvent and using two solvents are demonstrated.
Laboratory Equipment / Apparatus |
Separation Science
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Separating and Purifying
Laboratory processes frequently used to separate mixtures or purify substances including centrifuging, chromatography, distillation, extraction, filtration, and recrystallization are demonstrated.
Laboratory Equipment / Apparatus |
Separation Science
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Chromatography
Chromatographic techniques including the gas chromatography, paper chromatography, and thin layer chromatography are demonstrated.
Chromatography |
Separation Science |
Laboratory Equipment / Apparatus
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Solids-Liquids
Reactions and demonstrations exploring the properties of solids and liquids.
Solids |
Liquids
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Scattering and Absorption of Light
The effects of passing light through a colloidal suspension of milk in water and through a solution of copper sulfate are shown.
Colloids |
Physical Properties |
Liquids
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Viscosity of Liquids
The viscosities of water, 2-propanol (rubbing alcohol), ethylene glycol (antifreeze) and vegetable oil are compared. The viscosities of water, hexane, octane, 2,2,4-trimethylpentane and 1-pentanol are measured.
Liquids |
Physical Properties
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Electrical Conductivity-Liquids
The conductivity of liquids are tested.
Conductivity |
Liquids |
Physical Properties
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Vapor Pressure: Drinking Bird
A novelty store "Drinking Bird" repeatedly dips is beak into a beaker of water and then bobs back to an upright position. Visible movement of a liquid in the bird's body accompanies the bobbing; the movement is caused by changing vapor pressure of the liquid due to different temperatures at the bird's head and the bird's body.
Liquids |
Phases / Phase Transitions / Diagrams
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Measuring Relative Viscosity
The rate of flow of six different liquids through a Mohr pipet is measured.
Liquids |
Physical Properties |
Laboratory Equipment / Apparatus
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Paramagnetism: Nitrogen and Oxygen
A magnet is shown to strongly attract a pair of metal tongs. The magnet has no visible effect on liquid nitrogen, but when pale blue liquid oxygen is poured near the poles of the magnet, it shows definite attraction.
Magnetic Properties |
Atomic Properties / Structure |
Liquids
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Ferrofluid
A magnet placed just below a dish containing ferrofluid generates an array of spikes in the fluid.
Liquids |
Magnetic Properties |
Metals |
Atomic Properties / Structure
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Boiling by Cooling
A flask contains water and water vapor at 100C. Each time ice water is poured over the outside of the flask, the water inside the flask boils. Although the temperature of the water in the flask has decreased, in each instance boiling is observed.
Gases |
Liquids |
Phases / Phase Transitions / Diagrams
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Vapor Pressure: Molecular Size
The measurement of pressure exerted by a vapor is demonstrated using barometers. Vapor pressure varies with the strength of the intermolecular forces in the liquid.
Gases |
Liquids |
Noncovalent Interactions |
Phases / Phase Transitions / Diagrams |
Physical Properties
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Vapor Pressure of a Mixture: Raoult's Law
The measurement of pressure exerted by a vapor is demonstrated using barometers. Vapor pressure varies with the strength of the intermolecular forces in the liquid.
In this section we will look at vapor pressure of mixtures. We can calculate the vapor pressure of a mixture using Raoult's law.
Gases |
Liquids |
Noncovalent Interactions |
Phases / Phase Transitions / Diagrams |
Physical Properties
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Solutions
Reactions and demonstrations exploring the concepts of solutions.
Noncovalent Interactions |
Physical Properties |
Precipitation / Solubility |
Solutions / Solvents |
Calorimetry / Thermochemistry |
Applications of Chemistry |
Acids / Bases |
Aqueous Solution Chemistry |
pH |
Conductivity |
Reactions |
Titration / Volumetric Analysis |
Liquids |
Solids |
Equilibrium |
Transport Properties
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Enthlapy-Thermodynamics
Reactions and demonstrations the explore thermodynamic concepts.
Precipitation / Solubility |
Solutions / Solvents |
Calorimetry / Thermochemistry |
Applications of Chemistry |
Acids / Bases |
Physical Properties |
Reactions |
Thermodynamics |
Gases |
Phases / Phase Transitions / Diagrams |
Water / Water Chemistry |
Liquids |
Solids |
pH |
Consumer Chemistry |
Kinetics |
Oxidation / Reduction
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