An unknown element is a mixture of isotopes 129X and 132 X. The average
atomic mass of X is 129.91 amu.
What is the percent abundance of
132 X?

Calculate the number of moles of ethane in 100 grams

11. phosphorus-32 is radioactive and has a half life of 14 days. how much of a 124 mg sample of phosphorus-32 is present after 56 days? a) 7.75 mg b) 15.5 mg c) 31.0 mg d) 62.0 mg

Which of the following units is not an official si unit? mole liter kilogram ampere