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A liquid has two properties (amongst many) called cohesion and adhesion. Cohesion is the force of attraction between molecules/atoms of the liquid itself. Adhesion is the force of attraction between the molecules/atoms of the liquid and other substances. Therefore, if the molecules' attraction for another substance is greater than the attraction between the molecules, the molecules will preferentially interact with the other substance. When you have a substance that is more attracted to the walls of a capillary tube than itself (i.e. adhesion > cohesion), the substance will exhibit capillary action and form a concave meniscus. Mercury, however, has a stronger cohesive force between its atoms than adhesive force to the walls of a capillary tube, and therefore will not preferentially interact with the tube, thus not demonstrating capillary action and forming a convex meniscus. Curved surfaces have a higher pressure (called LaPlace pressure) on the concave side of the curve than on the convex side. Because mercury has a convex meniscus it has a lower LaPlace pressure in the capillary than the surrrounding liquid. It will therefore show a capillary drop rather than the more common capillary rise seen with materials that have a concave meniscus like water.
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What we called the tendency of liquid molecules to rise spontaneously up tubes with narrow diameters?
That is capillary attraction.
How far does the mercury rise in the capillary when the temperature changes from 0.0 to 25.0?
5
Why does mercury fall downwards and water rise upwards when placed in a capillary tube?
Mercury is more dense than water.
What is the basic use of capillary tube?
Capillary tubes are used in refrigeration and air conditioning systems to control the flow of refrigerant into the evaporator. They work by restricting the flow of refrigerant to create a pressure difference between the high and low sides of the system, allowing for the cooling process to occur efficiently.
What is the attraction between molecules that result in the rise of liquid in small tubes?
capillarity, also known as capillary action.
What is the definition of Glass thermometer?
thermometer consisting of mercury contained in a bulb at the bottom of a graduated sealed glass capillary tube marked in degrees Celsius or Fahrenheit; mercury expands with a rise in temperature causing a thin thread of mercury to rise in the tube
Why mercury falls in capillary tube?
Mercury falls in a capillary tube due to the combination of capillary action and gravity. Capillary action is the tendency of a liquid to be drawn up into a narrow tube against the force of gravity. When the adhesive forces between the mercury and the walls of the capillary tube are greater than the cohesive forces within the mercury, the mercury will move downward in the tube.
Why there is capillary action and why the effect is greater for narrower tubes?
Liquid rises in and out of cappilarry to compansate pressure difference. Rise of a liquid in capillary is indirectly proportional to radius of tube so liquid goes higher in a narrow tube.
Why is water rise in capillary tube wheras mercury falls in capillary tube?
This happens due to the difference in adhesive and cohesive forces. Water molecules are more attracted to the walls of the tube (adhesive forces) than to each other (cohesive forces), causing water to rise. Mercury has stronger cohesive forces compared to adhesive forces, so mercury is more attracted to itself than to the walls of the tube, causing it to be depressed or fall in the capillary tube.
What it the definition of capillary motion?
Capillary motion is a movement of liquids in small tubes. This motion can be also ascensional.
Which part of the thermometer contains the mercury?
The internal capillary contain mercury.
What is the advantage of using a plastic capillary tube when collecting blood?
Plastic capillary tubes are advantageous because they are disposable, reducing the risk of contamination between samples. They are also less fragile compared to glass capillary tubes, reducing the risk of breakage during sample collection and handling. Additionally, plastic capillary tubes are more cost-effective and easier to dispose of after use.
