A sample of neon contains (mass 19.9924 u), (mass 20.9940 u), and (mass 21.9914 u). Calculate to 4 significant figures the average atomic mass of neon in this sample.
A sample of magnesium contains (mass 23.98 u), (mass 24.99 u), and (mass 25.98 u). Calculate the average atomic mass of magnesium in this sample.
What is the molar mass of methane ()?