6. organic analysis

• What is used to test for alcohols?

  Acidified potassium dichromate
• How does acidified potassium dichromate distinguish alcohol types?

  It oxidizes primary and secondary alcohols
• What color change indicates the presence of primary or secondary alcohols?

  Orange to green
• What happens to tertiary alcohols when treated with dichromate?

  They remain orange
• Why can't primary and secondary alcohols be distinguished by dichromate alone?

  They both give the same color change
• What method is used to separate products from alcohol oxidation?

  Fractional distillation
• What does the formation of an aldehyde indicate about the initial alcohol?

  The initial alcohol was primary
• What does the formation of a ketone indicate about the initial alcohol?

  The initial alcohol was secondary
• What is Fehling's solution used for?

  To distinguish between aldehydes and ketones
• What color is Fehling's solution before use?

  Blue
• What happens when Fehling's solution is added to an aldehyde?

  It turns from blue to brick red
• What happens when Fehling's solution is added to a ketone?

  It remains blue
• What is Tollens' reagent used for?

  To distinguish between aldehydes and ketones
• What is the appearance of Tollens' reagent before use?

  Colorless
• What is produced when an aldehyde is added to Tollens' reagent?

  Silver precipitate coats the flask
• What happens when a ketone is added to Tollens' reagent?

  No silver precipitate forms
• How do you test for alkenes?

  Add bromine water
• What indicates the presence of an alkene when bromine water is added?

  A colorless solution forms
• What reaction occurs when bromine water reacts with an alkene?

  Formation of dibromoalkane
• What is the test for carboxylic acids?

  Add a carbonate
• What gas is produced when a carboxylic acid reacts with a carbonate?

  Carbon dioxide
• What happens to lime water when carbon dioxide is present?

  It turns cloudy
• Why is it not definitive to identify a carboxylic acid using carbonates?

  Other acids can also produce carbon dioxide
• What is mass spectrometry used for?

  To find the relative molecular mass
• What does the m/z ratio represent in mass spectrometry?

  Mass divided by charge
• What does the m plus 1 peak indicate?

  The mass of the original molecule
• What is high-resolution mass spectrometry used for?

  To identify molecules with the same mass
• How does high-resolution mass spectrometry improve upon standard mass spectrometry?

  It provides more decimal places for mass
• Which three compounds have the same molecular mass of 44?

  Ethanol, propanol, and butanol
• Why is it difficult to distinguish between ethanol and propane using mass spectrometry?

  They have the same molecular mass
• What technique improves the identification of molecules with the same molecular mass?

  High resolution mass spectrometry
• How does high resolution mass spectrometry differ from standard mass spectrometry?

  It measures mass to several decimal places
• Why is high resolution mass spectrometry important for distinguishing between ethanol and propane?

  They have the same molecular mass rounded
• What does infrared (IR) spectroscopy use to increase vibrational energy in bonds?

  Infrared radiation
• What factors affect the frequency of infrared radiation absorbed by a bond?

  Atoms on either side of the bond
• What is indicated by a peak around 3000 cm-1 in an IR spectrum?

  Presence of an O-H bond
• What does a broad peak in an IR spectrum suggest about a compound?

  It may indicate the presence of an acid
• How can the fingerprint region in IR spectroscopy be used?

  To identify specific molecules
• What does the fingerprint region in IR spectroscopy range from?

  500 cm-1 to 1500 cm-1
• How does the fingerprint region relate to identifying compounds?

  It compares peaks to a library of spectra