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2021-06-17

What is the function of the hot filtration step during recrystallization?

What is the function of the hot filtration step during recrystallization?

A hot filtration is used for filtering solutions that will crystallize when allowed to cool. It is therefore important that the funnel is kept hot during filtration through contact with hot solvent vapors, or crystals may prematurely form on the filter paper or in the stem of the funnel (Figure 1.82).

What should you do if you see crystals or cloudiness in the bottom of the filter flask during vacuum filtration?

The proper way to wash the crystals is to SHUT OFF the vacuum, add a minimum amount of cold solvent so that the crystals are barely sitting in solvent for about 5 Page 4 seconds (the solvent will not drip through quickly) and then apply the vacuum. The solvent will be sucked into the filtrate.

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What should you do every time you are setting up glassware for a vacuum filtration select one or more?

What should you do every time you are setting up glassware for a vacuum filtration? Select one or more: 1….Select one or more:

  1. Check that there are no cracks or defects in the glassware.
  2. Ensure that the glassware is designed for use with a vacuum.
  3. Dry the outside of all the glassware.
  4. Inspect the tubing for any holes.

Why is suction filtration used?

Suction filtration (vacuum filtration) is the standard technique used for separating a solid-liquid mixture when the goal is to retain the solid (for example in crystallization). 2) Suction filtration is more efficient at removing residual liquid, leading to a purer solid.

What is the purpose of Celite?

Diatomaceous earth (sometimes referred to by trademarked brand names such as Celite) is used in chemistry as a filtration aid, to increase flow rate and filter very fine particles that would otherwise pass through or clog filter paper.

Is Celite and water a mixture or solution?

Celite is a silicaceous mixture of diatoms and does not form colloids in a similar fashion to silica. Personally I have never had problems with celite interacting with MeOH/water/acid/base, finding it to be an ideal filtrating agent.

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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 do you moisten the filter paper in the Buchner funnel before you apply the suction?

The filter paper is moistened with the solvent that makes up the solution. This prevents the formation of multi-layer systems in the filter flask. It should adhere well to the bottom before the vacuum is applied. Figure 3: Büchner funnel with filter paper extending up the side.

Should you use one or two coffee filters?

The short answer is: you should not be using 2 coffee filters routinely. Using 2 paper filters when brewing coffee increases the brew time. The flow of water is slower, as water needs to pass through 2 layers of filter. Therefore, coffee typically comes out stronger, but over-extracted and bitter.

What can I use if I dont have coffee filters?

5 Clever Coffee Filter Substitutes

  1. Paper Towels & Napkins (Most Common) Using a paper towel or a napkin as a coffee filter is the most common solution.
  2. Fine Mesh Sieves (Flavorful, But With Grounds)
  3. Cloth Napkin or Dish Towels (Convenient, Not Always Tasty)
  4. Reusable Tea Bags (Least Common)
  5. No Filter At All (Easiest)
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Should you use paper filters for coffee?

Paper filters cost more over time, but are practically mess-free. Paper filters produce a brighter, sweeter cup of coffee with little or no sediment or oils, helping cut out the bad cholesterol found in coffee.

Do you use a paper filter with the gold filter?

That said, there are health reasons to use paper filters, because of the cafestol in coffee. But with a gold filter, the cafestol drips right through. So, for aesthetics choose the gold filter, and for your health choose the paper.