Chemical Analysis Flashcards
3 requirements for titrimetric analysis
- goes to completion
- should be rapid
- determinable end point
4 advantages of titrimetry
- high precision
- robust method
- inexpensive equipment
- can be automated
3 disadvantages of titrimetry
- not selective
- high level of operator skill
- large amounts of analyte and reagent required
3 common types of titrimetry
- Acid-base
- Redox
- Metal complexation
What is a primary standard?
solids available in high purity
What is a secondary standard?
reagents that have been standardised against a primary standard
How is the endpoint measured in automated titrations?
changes in conductivity
When do you use back titration?
when reactions are slo or an excess of reagent is required to achieve completion
What is blank titration?
glassware reacts with NaOh and KOH so second experiment must be carried out if prolonged exposure
5 uses of IR Spectroscopy
- a qualitative fingerprint check of raw materials
- for following reactions
- for solids or semisolids
- detecting polymorphs of drugs
- provides a complex, unique fingerprint region
5 limitations of IR Spectroscopy
- not a quantitative method
- can only detect gross quantities
- requires a degree of skill
- often lacks robustness
- different compounds can look similar
How does MRI work?
- strong magnetic fields to provide a 3D image of the body
- sensing the environment of water molecules in body tissues, H nuclei report on their local region
What is a chromophore?
the part of molecule that is responsible for absorption in vivible region of the spectrum
What is an auxophore?
a functional group that has no such absorption of its own but which modifies the absorption properties of the chromophore
What are the 4 easy fragment ions?
- 43 H3C -=o -x
- 77 benz-x
- 91 benz–x
- 105 benz -=O-x
