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A-level Chemistry Yr 13 Mine > 29 - Chromatography and Spectroscopy > Flashcards

29 - Chromatography and Spectroscopy Flashcards

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1
Q

How do you test for Alkenes?

A

Bromine Water

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2
Q

How do you test for Haloalkenes?

A

Silver Nitrate

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3
Q

What are the two reaction you do for testing for phenols?

A
  1. Test with Sodium Hydroxide.
    Testing for the weak acidic nature of phenols. Sodium hydroxide is a strong base and so will react with any acid.
  2. Test with Carbonate.
    Carbonate is a much weaker base than sodium hydroxide. Carbonates will only react with strong acids, not weak acids, such as phenol.
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4
Q

How do you test for Phenols with Sodium Hydroxide?

A
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5
Q

How do you test for Phenols and carbonate?

A
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6
Q

How do you test for Carboxylic Acid?

A

Sodium Carbonate

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7
Q

Why can you use carbonates to test for Carboxylic Acids and not Phenol?

A

Carboxylic acids react with carbonates to form a salt, CARBON DIOXIDE and water.

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8
Q

How do you test for Carbonyl Group (Aldehydes and Ketones) ?

A

Use 2,4-DNP , 2,4-dinitrophenylhydrazine

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9
Q

How do you test for Aldehydes?

A
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10
Q

How do you test for Primary and Secondary Alcohols?

A
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11
Q

Why is Chromatography used ?

A

Separate components out of a mixture.

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12
Q

What are the two types of Chromatography?

A

Thin-layer chromatography (TLC) and Gas Chromatography

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13
Q

Why is it called Thin-layer chromatography?

A

Because a glass or plastic plate is covered wit thin layer of Silica Gel or Aluminium powder.

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14
Q

What is the method for setting up Thin-layer Chromatography?

A
  1. Take a sheet of plastic coat in thin layer of silica gel.
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15
Q

How do you calculate Rf values?

A

Rf Value = distance travelled by spot / distance travelled by solvent

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16
Q

Why is thin-layer chromatography better than paper chromatography?

A

More accurate to analyse.
Get distinct dots with TLC, whereas in PC the components spread out more.

17
Q

How can you identify each component in the TCL plate?

A

Calculate the Rf value and look this value up into the table of know values.

18
Q

What is the moving phase and stationary phase in chromatography?

A

Moving Phase - whatever moves the components (solvent)

Stationary phase - whatever the moving phase moves through (silica gel / aluminium powder)

A-level Chemistry Yr 13 Mine (12 decks)

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