Organic analysis

• What is the first chemical test mentioned for identifying alcohols?

  Using acidified potassium dichromate
• What does acidified potassium dichromate oxidize?

  Primary and secondary alcohols
• What color change indicates the presence of primary or secondary alcohols when using potassium dichromate?

  From orange to green
• What happens to tertiary alcohols when treated with potassium dichromate?

  They remain orange
• Why is fractional distillation used after oxidizing alcohols?

  To separate the products for further testing
• What is formed from the oxidation of primary alcohols?

  Aldehydes
• What is formed from the oxidation of secondary alcohols?

  Ketones
• What is failing solution used for?

  To distinguish between aldehydes and ketones
• What color change occurs when failing solution reacts with aldehydes?

  Blue to brick red precipitate
• What happens to failing solution when it reacts with ketones?

  It remains blue
• What is Tollen's reagent used for?

  To distinguish between aldehydes and ketones
• How is Tollen's reagent prepared?

  By mixing silver nitrate, sodium hydroxide, and dilute ammonia
• What indicates the presence of an aldehyde when using Tollen's reagent?

  A silver precipitate coats the inside of the flask
• What happens when Tollen's reagent reacts with ketones?

  No silver precipitate is formed
• What is the test for alkenes?

  Adding 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 a dibromoalkane
• What is the test for carboxylic acids?

  Adding 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 important to confirm the presence of a carboxylic acid with other techniques?

  Other acids can also produce carbon dioxide
• What does mass spectrometry determine?

  The relative molecular mass of a compound
• What does the m/z value represent in mass spectrometry?

  The mass-to-charge ratio of a fragment
• What is the molecular ion peak in mass spectrometry?

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

  To identify molecules with the same molecular mass to several decimal places
• Which two compounds have the same molecular mass of 44?

  Ethanol and propane
• Why is high-resolution mass spectrometry important in organic analysis?

  It helps distinguish between different molecules with the same rounded molecular mass
• What technique is used to improve 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 provides mass measurements to several decimal places instead of rounding to the nearest whole number.
• If ethanol and propane both have a molecular mass of 44 when rounded, how can they be distinguished?

  By using high resolution mass spectrometry to measure their precise masses.
• What are the precise molecular masses of ethanol and propane when calculated to four decimal places?

  Ethanol is 44.0302 and propane is 44.0624.
• What does infrared (IR) spectroscopy use to increase the vibrational energy of bonds in a sample?

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

  The atoms on either side of the bond and the position of the bond in the molecule.
• How can the infrared spectrum of ethanoic acid be interpreted?

  By identifying peaks that correspond to specific functional groups, such as the O-H bond in acids.
• What does a peak around 3000 cm^-1 in an IR spectrum suggest?

  It suggests the presence of an O-H bond, indicating an acid.
• What is the fingerprint region in infrared spectroscopy?

  It is the region between 500 cm^-1 and 1500 cm^-1 that contains unique peaks for specific molecules.
• How can the fingerprint region be used in molecular identification?

  By comparing the unique set of peaks to a library of known spectra.
• What happens if there are extra peaks in the fingerprint region of an IR spectrum?

  It indicates the presence of impurities in the sample.
• What are some examples of greenhouse gases?

  Carbon dioxide, water vapor, and methane.
• How do greenhouse gases contribute to global warming?

  They absorb infrared radiation and re-emit it back towards the Earth, preventing heat from escaping.