crookes tube

Examples of crookes tube in the following topics:

• Cathode Rays

  • Cathode rays are electron beams or streams of electrons that were observed for the first time in Crookes tubes (vacuum tubes).
  • The early cold cathode vacuum tubes, called Crookes tubes, used a high electrical potential between the anode and the cathode to ionize the residual gas in the tube.
  • These were called Crookes tubes.
  • Crookes found that as he pumped more air out of the tubes, the Faraday dark space spread down the tube from the cathode toward the anode, until the tube was totally dark.
  • A Crookes tube is a rarefied tube evacuated to a pressure below 10−6 atm.

• Capillary Action

  • Notice that the height to which the liquid is lifted is inversely proportional to the radius of the tube, which explains why the phenomenon is more pronounced for smaller tubes.
  • A common apparatus used to demonstrate capillary action is the capillary tube.
  • When the lower end of a vertical glass tube is placed in a liquid, a concave meniscus forms.
  • The rise or fall of liquids in a capillary tube depends upon the interactions between the tube and the liquid.
  • The meniscus curve on a column of fluid in a capillary tube

• Gas Evolution Reactions

  • The test tube on the right contains limewater (a solution of calcium hydroxide, Ca(OH)2).
  • The test tubes are sealed with rubber stoppers and connected with a delivery tube.
  • In this reaction setup, lime water is poured into one of the test tubes and sealed with a stopper.
  • A small amount of hydrochloric acid is carefully poured into the remaining test tube.
  • The two tubes are connected.

• Collecting Gases Over Water

  • A common way to determine the amount of gas present is by collecting it over water and measuring the height of displaced water; this is accomplished by placing a tube into an inverted bottle, the opening of which is immersed in a larger container of water.
  • The total pressure in the tube can be written using Dalton's Law of Partial Pressures:
  • Because the height of the water inside the tube is equal to the height of the water outside the tube, the total pressure inside the tube must be equal to the atmospheric pressure.

• Detection and Observation of Radicals

  • The Paneth experiment involved gas phase thermal decomposition of tetramethyllead to methyl radicals and lead atoms in a glass tube.
  • The initial flow of the lead compound through the tube is shown in the following illustrations, and the consequences of applying strong heat to the tube will be displayed.

• Osmotic Pressure

  • Imagine osmosis taking place in an upright U-tube.
  • On the left side of the U-tube is an aqueous solution, and on the right side is pure water.

• Boyle's Law: Volume and Pressure

  • Boyle showed that the volume of air trapped by a liquid in the closed short limb of a J-shaped tube decreased in exact proportion to the pressure produced by the liquid in the long part of the tube.
  • The difference between the heights of the two mercury columns gives the pressure (76 cm = 1 atm), and the volume of the air is calculated from the length of the air column and the tubing diameter.

• Combustion Analysis

  • In combustion analysis, the products, carbon dioxide and water vapor, are trapped by absorption onto reactive solids located in tubes above the reaction vessel.
  • These tubes can then be weighed to determine the absorbed masses of carbon dioxide and water.

• Cationic Chain-Growth Polymerization

  • The polyisobutylene product is a soft rubbery solid, Tg = _70º C, which is used for inner tubes.

• Predicting Precipitation Reactions

  • Imagine you have two test tubes and three solutions: copper (II) chloride (CuCl2) solution, sodium carbonate (Na2CO3) solution, and sodium sulfate (Na2SO4) solution.
  • You put 5 mL of copper (II) chloride into tubes 1 and 2.
  • You add 5 mL of sodium carbonate in tube 1.
  • You carefully add the sodium sulphate solution into tube 2.