Experimental Determination of Structure Flashcards
Characteristics of a primary standard
High purity
Stable in air and solution
Soluble in solvents such as water
Large GFM/RFM
Why do primary standards require high purity
To ensure the mass weighed out is the mass of the required chemical resulting in minimised error on the actual mass of the required chemical
Why do primary standards have to be stable in air and solution
Some of the required chemical will react with the air or solution if unstable in these conditions resulting in there being less chemical than what was weighed out
Why do primary standards have to be soluble in water or other solvents
To allow for high masses of solute to dissolve which allows for high concentration solvents to be prepared
Why do primary standards have a high GFM
To minimise error and uncertainty of the numbers of moles of a substance weighed out
What are primary standards
Chemicals which can be used directly to produce standard solutions
Mass spectrometry procedure
- A sample of the compound is bombarded with electrons
- Removing electrons from the sample and producing a positively charged molecule
- The molecule breaks into smaller ion fragments
- A mass spectrum is then plotted using mass charge ratio and percentage abundance
Parent Ion
The largest positively charged ion in a mass spectrum
Mass Spectrometry Definition
Where electrons bombarded a sample to produce positively charged ions, allowing the mass to charge ratio and abundance to be determined
Infrared spectroscopy procedure
- Infrared radiation will be passed through a sample
- A detector will measure the infrared radiation which is transmitted through a sample and determine the absorbance of the sample
Units for wave number
cm^-1
wave number formula
1/wavelength
Where can wave-numbers be found
page 15 of the data booklet
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