Stoichiometry: Rounding

For this site we will use two decimal places when rounding the gram atomic mass from the periodic table. This is to ensure consistency in our calculations so we can compare numbers. For example, my periodic table reports hydrogen (H) as 1.0079 g/mol. I round this to 1.01 g/mol. More examples:

  • Ne = 20.1797 and rounds to 20.18
  • Si = 28.0855 and rounds to 20.09
  • Tc is reported as (98) on my table. I round this to 98.00
  • Sc = 44.955912 and rounds to 44.96
  • Mg = 24.305 and rounds to 24.31

When finding the GFM of a compound the final answer should also be rounded to two decimal places.

If you end up with a whole number you still need to have two places after the decimal. In this case you should add .00 . For example, the GFM for O2 is written as 32.00 .