mass spectrometer

what are all measurements of mass compared to

they are relative to carbon-12

what is the definition of relative atomic mass (RAM)

the relative atomic mass of an atom is the ratio of the average mass of one atom of that element to 1/12th of the mass of one atom of carbon-12

what is the definition of relative molecular mass (MR)

the relative molecular mass of a molecule is the ratio of the average mass of that molecule to the 1/12th of the mass of an atom of carbon-12

what are the 5 stages of a mass spectrometer (VIADD)

• vaporisation

• ionisation

• acceleration

• deflection

• detection

explain the first process in a mass spectrometer ( vaporisation)

atoms in a sample are heated to turn the sample into a gass form

explain the second process in a mass spectrometer ( ionisation)

a heated filament ( or electron gun) emits electros in order to ionise the gaseous atoms into positive ions

explain the third process in mass spectrometer ( acceleration )

negatively charged plates to cause an electric field, resulting in the ions to focus into a beam and become accelerated

explain the fourth process in mass spectrometer ( deflection)

the electromagnet causes the charged ions to become deflected by the magnetic field and forced onto the detector

explain the fifth process in a mass spectrometer ( detection)

electric current measured as ions land on plate. the greater the abundance of the isotope, the larger the current.

state the type of deflection seen if the sample had a high mass

less deflection

state the type of deflection seen if the sample has a high charge

more deflection

what can you do to change the strength of deflection

change the strength of the electromagnet

give the formula to work out the relative atomic mass of an element from it mass spectrum

RAM= percentage abundance of each isotope X mass of each isotope / 100