Question

a new atomic mass scale is defined in which chromium was chooses at the standard with a mass of 25.00 amu. what would be the mass of oxygen on the new scale

Answer 1

Ans. Exact atomic mass of Chromium = 51.9961 g/ mol

Given,

            On new scale, atomic mass of Cr = 25.00 amu

So,

            25.00 amu is equivalent to 51.9961 g/ mol

            Or, 1 amu = (51.9961 g/ mol) / 25.00 = 2.079844 g/ mol

            Or, 1 g/mol = 0.48080529 amu

# Exact mass of O = 15.9994 g/ mol

Now, using 1 g/mol = 0.48080529 amu

            15.9994 g/ mol = 15.9994 x 0.48080529 amu = 7.6926 amu

Hence, atomic mass of O-atom on new scale = 7.6926 amu