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Why is the molecular sieving matrix swelled prior to packing the column?
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What is a process column?
A process column is a vertical cylinder in which a reaction takes place. The reaction is commonly one of filtering or selection, as measured by ionic charge; or molecular size and so on. Often an ion-exchange resin is used as the process material. A particular type of process column is the fractionating column, beloved of the petrochemical industry. These are tens of metres high, and rely on the fact that as the pressure reduces up the column, the boiling point of the (liquid) will change. Thus the high b.p material comes off lower down, and lower b.p. come off at higher levels.
In a two column proof the second column states your reasons for the corresponding statements in the first column?
true
What digit is in the tenths column of 46.2?
The tenths column is the first column after the decimal point, so it is 2.
What is the thousandths column of 0.123?
.003 would be in the thousandths column.
What is the tenths column of the number 18.5?
The 5 is in the tenths column.
Difference between tray and packed columns?
Packed column consist of porous substance as a packing in the column which provides contact between the fluids used,while different types of trays are used depending on the ease of separation instead of a packing in a usual tray column.
Which column illustrates the primary and subsidiary hazards of a hazardous material?
Which one of the following three hazards takes precedence? -a toxic subatance (class 6.1 packing group i - dermal -a flammabel liquid ( class 3 packing group ii) - a corrosive substance ( class 8 liquid packing group ii)
What problems may arise in the use from a poorly packed liquid chromatography column?
The effect of packing a chromatographic column unevenly will cause the flow to be uneven down the column and lead to poor separation.
What is liquid holdup in a column?
'Liquid Hold-up' in a distillation column refers to down-coming liquid (liquid traffic travelling down the column) becoming trapped in the column's packing material. Packing material is used in distillation columns to increase the contact efficiency between the down-coming liquid stream(s) and the up-flowing vapour stream(s). The packing materials do this by increasing the surface-to-volume ratio over which the vapour and liquid streams come into contact in order to promote separation between the more volatile and less volatile components in the column. The down-coming liquid can become trapped in the packing material for a number of reasons. One example is when liquid becomes trapped in crack formations or fractures of the packing material (which can occur during normal or non-steady state column operation). When the liquid becomes trapped in these cracks/crevices, contact with the up-flowing vapour stream becomes non-existent and the liquid is literally 'held up' from travelling down the column.
What is a column plate number?
It is the efficiency of the column. The larger the number, the more theoretical plates the column possesses; a typical well-packed column with a 5-micrometer particle size porous packing in a 15cm x 46 mm column should provide10,000-20,000 plates. sorry. I forgot to put a point in there. It should be 4.5 mm, not 45
What is the superficial velocity?
Superficial velocity is nothing but the velocity of a fluid in a pipe,conduit,column etc in the absense of packing or obstruction. like in packed columns the actual velocity of the fluid through it is actually the volumetric flow rate divided by the cross sectional area. so the velocity achieved by the same fluid in the same column in absence of the packing is called superficial velocity.
How do you select hplc column in method development?
firs you mist know the polarity for sample, wen the sample polar you can use "RP" column like C18 or C8 ( C18 first in pharmaceutical) . wen sample non polar use "NP" column like silica or CN Column. after that you can change the column in same packing to solve tailing, retention time, Resolution..... or any problem by change column length, particle size or carbon loud
Would you that mixing gases is a reversible change?
It isn't easily reversible but, it is reversible. You can use a molecular sieve or a distillation column to separate them.
Is xenon molecular or atomic?
Xenon (Xe) can be found on the periodic table in the far right column (Noble Gases) and is thus an element, not a molecule.
Why are the plates in column chromatography called 'theoretical plates'?
The number of theoretical plates in a chromatography column is a measure of how "long" the column is - how well it separates. A "short" column will only separate large or heavy molecules, and the medium and light stuff is still mixed together in the last band. A "long" column will separate the little stuff better because there are more theorectical plates. Picture a stack of sieves with smaller and smaller holes as the column gets "longer" and you've got the idea. This "length" has virtually nothing to do with the physical length of the separating column. It is a function of the packing materials and solvents used during a separation.
What has the author Gary L Hundley written?
Gary L. Hundley has written: 'Performance of a packed distillation column with induction heated packing' -- subject(s): Distillation apparatus, Packed towers
Why does the diameter of distillation column vary at different location?
A distillation column has flows of materials going up and down the plates or packing. The flow across each plate or section of packing is an essential factor in the optimization calculations and design. Diameter is one of these considerations. Since columns have "heavies" traveling down and "lights" moving up and the division between these components may not be even, the top and bottom flows may be quite different, and the optimal column diameter must be adjusted at different locations along the length. Add to this the introduction of a feed stream at some point in the mid-column and the flows are altered again. But why be concerned about this? Columns are often constructed of expensive alloys, glass lined, or heat treated to avoid erosion, corrosion or stress problems. Minimizing the column size minimizes the cost. Along with quality of product, cost is an optimization factor.
