Atomic Structure - RAM CALC 2

Question 1

What is the relative atomic mass?

Answer 1

The average mass of an atom of an element relative to 1/12th of a carbon-12 atom.

Question 2

What is relative molecular mass?

Answer 2

Average mass of a molecule relative to 1/12th of the mass of an atom of carbon-12.

Question 3

What is the relative isotopic mass?

Answer 3

Mass of an atom of an element relative to 1/12th of the mass of an atom of carbon-12

Question 4

how does mass spectrometer show the abundance and mass of an isotope?

Answer 4

A sample passes through and the spectrum is produced of mass/charge (m/z) ratio against abundance

Question 5

What is the molecular ion peak? (M+)

Answer 5

The peak with the highest mass

Question 6

What is the base peak?

Answer 6

Peak which has the largest abundance

Question 7

How do you calculate the relative atomic mass from a mass spectrometer?

Answer 7

multiply the relative isotopic abundance (%) on the y-axis by the m/z on the x-axis for each isotope to get total mass. Add these up and divide by 100

Question 8

how to calculate the abundances of each isotope in a mass spectra?

Answer 8

• multiply the combination pairs
• get the fractions and convert it into percentages
• add the mass numbers of the isotopes (don’t add two of the same one)
• plots on graph