Determine the average atomic mass of helium, which has two isotopes having atomic masses 4.0026 amu and 3.0160 amu. the relative abundance of the two isotopes is 99. percent and 0.0001 percent, respectively.

4. propanol and isopropanol are isomers. this means that they have a) the same molecular formula but different chemical properties. b) different molecular formulas but the same chemical properties. c) the same molecular formula and the same chemical properties. d) the same molecular formula but represent different states of the compound