What is a carbonyl group and what are their properties?

A carbonyl group is a carbon bonded to a oxigen with a double bond. The group has sigma and pi bonds, resulting in a planar structure and with a electron density is closer to the oxigen. This group is present in many organic compounds and is characteristic in several functional groups (aldehyde, ketone, carboxilic acid, amide, ester, aclyl halide and anhydride acid). In spectroscopy the signal of this group is unique and easy of spot, infrared absorption is around 1800 cm-1 and in 13C NMR the signal has a chemical shift between 160 to 220 ppm depending on the surroundings

What is an internal standard and how is used in analytical methodologies?

An internal standard is a compound similar to the analite added to standards, blanks and samples. In the quantification analysis instead of using analite response, ratio of response between analite and internal standard is used, it helps to reduce instrumental variability

What is a colligative property?

Colligative properties are properties of solutions that depends on the quantity of particles (solute) in a determined quantity of solvent (volume or mass) but not in the particular properties of the compound in solution. The colligative properties and it's behavior are: lowering vapor pressure, increase of boiling point, decrease of freezing point and osmotic pressure