Table of Contents
Does mercury have convex meniscus?
Formation of a Meniscus Mercury does not wet glass – the cohesive forces within the drops are stronger than the adhesive forces between the drops and glass. When liquid mercury is confined in a tube, its surface (meniscus) has a convex shape because the cohesive forces in liquid mercury tend to draw it into a drop.
What type of meniscus has mercury?
Mercury metal forms a convex meniscus in glass vessels.
Why mercury forms a convex meniscus?
When mercury is placed in a graduated cylinder, the cohesive forces in the mercury are stronger than the adhesive forces between the mercury and the glass. The strong cohesive forces within the mercury pull it together forming a convex shaped meniscus.
What are the examples of convex meniscus?
A convex meniscus appears when molecules of liquid are strongly attracted to each other rather than to the wall of container. Most liquids, including water, show a concave meniscus but a great example of a convex meniscus is liquid mercury in a glass container.
Where is the mercury meniscus measured?
For mercury, take the measurement from the top of the meniscus. In either case, you are measuring based on the center of the meniscus. For a flat meniscus, make sure the liquid is level.
How do you read a convex meniscus?
If the meniscus is a concave meniscus, read at the lowest level of the curve. If the meniscus is convex, take your measurement at the highest point of the curve. The short answer: Take your measurement from the center of the meniscus. It’s that easy.
When mercury is kept in glass meniscus is?
A convex meniscus occurs because, as with mercury and glass, the molecules have a greater attraction to each other than to the container.
Why is mercury cohesive?
Formed bonds are called hydrogen bonds which lead to strong cohesive forces between the water molecules and high surface tension of water. As mercury is a metal, the bonds between the molecules are metal bonds that are much stronger than the hydrogen bonds leading to very high cohesive forces and high surface tension.
What is meant by meniscus of mercury?
The meniscus (plural: menisci, from the Greek for “crescent”) is the curve in the upper surface of a liquid close to the surface of the container or another object, caused by surface tension. Convex menisci occur, for example, between mercury and glass in barometers and thermometers.
Why does liquid mercury have a convex meniscus?
Mercury has a convex meniscus because the cohesive forces in liquid mercury tend to draw it into a drop. The cohesive force within te drop are stronger. The cohesive force between glass and stronger are comparatively weaker.
What causes a concave meniscus in a glass tube?
It all depends on if the molecules of the liquid are more attracted to the outside material or to themselves. A concave meniscus, which is what you normally will see, occurs when the molecules of the liquid are attracted to those of the container. This occurs with water and a glass tube.
What kind of meniscus does water have?
Water has an upward meniscus, mercury has a downward meniscus.
Can a convex meniscus be made out of Teflon?
Many kinds of plastics, called “hydrophobic”, (e.g. teflon) have very small adhesive forces with water , and if you make a container out of these you will get a convex meniscus with water, too.