With a name like poly hydroxyl alcohol, it suggests that the alcohol has more than one alcohol group. Thus any alcohol with more than one hydroxyl is a polyhydroxyl alcohol. An example that pops into mind is ethanediol (CH2OHCH2OH) this has 2 hydroxyl groups and is an alcohol, thus a polyhydroxyl alcohol
atomic mass=percentage of isotope a * mass of isotope a + percentage of isotope b * mass of isotope b+...+percentage of isotope n * mass of isotope n.
Data:
mass of isotope₁=267.8 u
percentage of isotope₁=90.3%
mass of isotope₂=270.9 u
percentage of isotope₂=9.7%
Therefore:
atomic mass=(0.903)(267.8 u)+(0.097)(270.9 u)=
=241.8234 u + 26.2773 u≈268.1 u
Answer: the mass atomic of this element would be 268.1 u
A scientific theory is a well tested explanation of a natural phenomenon.