What is a Craig tube best for?

Craig tubes are particularly useful for recrystallizing amounts of solid less than ~100 mg, the main advantage being that it minimizes the number of transfers of solid material and thus maximizes the yield of crystals.

How do you use Craig tube?

How much does a Craig tube weigh?

Specifications for this item
Brand NameSP Wilmad-LabGlass
Item Weight1.10 pounds
Length25 millimeters
MaterialBorosilicate Glass
Model NumberML-4090-622

What is the principle of recrystallization?

The principle behind recrystallization is that the amount of solute that can be dissolved by a solvent increases with temperature. In recrystallization, a solution is created by dissolving a solute in a solvent at or near its boiling point.

What is macroscale recrystallization?

What does a Hirsch funnel do?

Hirsch funnels are essentially smaller Büchner funnels and primarily used to collect a desired solid from a relatively small volume of liquid (1-10 mL). The main difference is that the plate is much smaller, while the walls of the funnel angle outward instead of being vertical.

How do you do gravity filtration?

What is a vacuum filtration apparatus?

Vacuum filtration uses a Buchner funnel and a side-arm flask. Vacuum filtration is faster than gravity filtration, because the solvent or solution and air is forced through the filter paper by the application of reduced pressure.

Why is a Hirsch funnel conical shaped used in preference to a Buchner funnel cylindrical shaped when filtering off the recrystallized product?

Unlike the Buchner funnel, the Hirsch funnel contains walls that angle outwards, and the size of the funnel is comparatively small. Therefore, this funnel is important in separating solids from a small volume of liquid.

What size filter paper should be used with a Hirsch funnel?

(~1.3 cm)
The filter paper has to cover all holes in the bottom of the funnel and does not extend up the sides. This means that the small pieces (~1.3 cm) of filter paper are used for the Hirsch funnel, and not a bigger circle hanging in the funnel.

How do you clean a Hirsch funnel?

Carefully add 15ml 30% hydrogen peroxide, or 1/3 the volume of sulfuric acid used, to the Büchner funnel and stand back! Let the reaction proceed for about a minute and then apply a quick vacuum (just enough to pull the solution through the sinter into the flask and the sinter is dry.)

Why a Buchner funnel is used to isolate the final crystallized product?

It is used in organic chemistry labs to assist in collecting recrystallized compounds. The suction allows the wet recrystallized compound to dry out such that the pure dried crystal compound is left remaining.

Why would a Hirsch funnel be more effective than a Buchner funnel for a small scale vacuum filtration?

Why would a Hirsch funnel be more effective than a Buchner funnel for a small-scale vacuum filtration? Hirsch funnels come in smaller sizes than Buchner funnels and the plate that holds the filter plate has a smaller surface area in Hirsch funnels.

Why is a Buchner funnel used instead of gravity filtration?

Filtration under vacuum using a Buchner funnel is used when you want to isolate the precipitate (the solid) for further work or analysis.

Why is vacuum filtration better than gravity filtration?

Vacuum filtration is faster than gravity filtration, because the solvent or solution and air is forced through the filter paper by the application of reduced pressure. The reduced pressure requires that they be carried out in special equipment: Büchner or Hirsch funnel.

What is Thistle funnel?

Thistle funnels are used to add small volumes of liquids to an exact position. Thistle funnels are found with or without taps. The thistle tube shaft is designed to allow insertion through a small hole present in some stoppers, permitting the tube to be inserted into a container such as an Erlenmeyer flask.

What are the two advantages of vacuum filtration?

Advantages: 1) Suction filtration is much faster than gravity filtration, often taking less than one minute with good seals and a good vacuum source. 2) Suction filtration is more efficient at removing residual liquid, leading to a purer solid.

Why does fluting a filter paper aid filtration?

Why does fluting a filter paper aid filtration? It decreases the contact area between liquid and glass to increase the speed of filtration. A filter paper may also be simply folded in quarters, however, this is not as efficient as fluting in terms of speeding up the filtration process.

When would you use gravity filtration?

Gravity filtration is generally used when the filtrate (liquid that has passed through the filter paper) will be retained, while the solid on the filter paper will be discarded.

What is the flask used in vacuum filtration?

Büchner flask
A Büchner flask, also known as a vacuum flask, filter flask, suction flask, side-arm flask, Kitasato flask or Bunsen flask, is a thick-walled Erlenmeyer flask with a short glass tube and hose barb protruding about an inch from its neck.

What is a stemless funnel?

A stemless funnel is used because crystals can form in the cool stem of a long-stem funnel and clog it. It is important that the glass setup is warm before starting the filtration.