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Structure of water molecule
The structure of water molecule is very simple. A water molecule is made up of one oxygen atom and two hydrogen atoms. The hydrogen atoms are covalently bonded to the oxygen atom by sharing a pair of electrons. The oxygen atom has two unshared electron pairs that makes a total of 4 electron pairs present ...
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Why does water have a higher surface tension than oil?
Water is polar, hydrogen bonds form between water molecules, so it results in higher surface tension. Oil is non-polar, hydrogen bonds does not form between oil molecules, so it leads to lower surface tension.
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The reasons why oil and water do not mix together
When I see drops of oil floating on water, at times, oil comes across as a stubborn liquid, which refuses to mix with water. At other times, I wonder whether it is water, to be blamed for not allowing oil to mix with it. Perhaps, both oil and water do not want to mix with each other or science does not ...
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Types of chromatographic column
If the chromatographic column is classified by functions, there are separation column and adsorption column. If the chromatographic column is classified by polarity, there are polar column and non-polar column.
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What makes the sample separated based on stationary phase?
Mainly on volatility, polarity, special effect, with or without hydrion.
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Several methods of chromatographic separation
1. Flush methodUse carrier gas to make mobile phase sample, inject quantitatively in short time.2. Replacement methodThe sample enters into column, then, replace the ouput column with a replacement agent.3. Head methodThe sample enters into chromatographic column continuously as mobile phase.
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Required conditions for increasing chromatographic resolution of column
1. Lower pressures at input port and output port;2. Smaller volume;3. Lower column temperature (column temperature increased 30 degrees, the retention time reduced by half)4. Smaller column diameter;5. Smaller sample quantity;6. Carrier gas with large molecular weight (small spreading);7. Evenly packing ...
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Types of gas chromatography detectors
1. Thermal conductivity detector (TCD)2. Flame ionization detector (FID)3. Helium ionization detector (HID)4. Electron capture detector (ECD)5. Flame photometric detector (FPD)6. Density balance detector (DBD)7. Cross-sectional area ionization detector (CID)
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Common adsorbents in actual use
The following adsorbents are commonly used for gas chromatograph column: active carbon, molecular seive, active alumina, graphitized carbon, bentonite and porous polymer bead etc.
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How long is the service life of high temperature capillary column
The service life of capillary column depends on its own quality and using conditions, including using temperature, sample condition and sample injection quantity etc. If the sample is clean, chromatographic column is not polluted and the capillary column applied within its using temperature range, the ...
