2.2 relative mass

Question 1

define relative isotopic mass

Answer 1

is the mass of an isotope relative to 1/12th of the mass of carbon -12

Question 2

define relative atomic mass and its other notaions

Answer 2

Ar: is the weighted mean mass of an atom of an element relative to 1/12th of the mass of an atom of carbon-12

Question 3

how do we determin the relative atomic mass

Answer 3

useing a mass spectrometer the vaporised ions are accelerated and heavier ones are harder to deflect so the individual ions are seperated and detectedand recorderd as a mass-to-charge ratio m/z relative mass of ion/relative charge on ion.

Question 4

relative atomic mass formula

Answer 4

Ar(ram)=(%xmass)+(%xmass)/100

Question 5

how do we determine the relative isotopic mass

Answer 5

can record m/z ratio accuratley using a mass spectrometer for each isotope so accurate relative isotopic masses can be measured.

Question 6

Do isotopes react differently?

Answer 6

Different ispotopes have the same number of electrons the number of neutrons has no effect on an element therefore react the same way.

Question 7

Do isotopes have different physical properties?

Answer 7

Minor differnece in physical properties can occur becuase with a higher mass isotope an element can have a higher BP and density eg heavy water

Question 8

What is meant by ‘the weighted mean’

Answer 8

takes into account
1. % abundance of each isotope
2. the relative isotopic mass of each isotope

Question 9

when do you need to use term: relative formula mass

Answer 9

For compounds with giant structures,

Question 10

when do you need to use term: relative molecular mass

Answer 10

For simple molecules

Question 11

mass spectrometry can aldo be used to record acurate of m/zratio of …..

Answer 11

each isotope so that accurate values of reklative isotopic mass can be measured

Question 12

what does m/z stand for

Answer 12

M stands for: relative mass of ion
Z stands for: relative charge of ion