A certain protein was found to contain 0.870% Cobalt by mass. Determine the minimum molecular mass of the protein in amu.

0.870% Cobalt by mass can be written as a ratio:

0.870 amu Co : 100.000 amu (total protein)

Therefore,

55.85 amu Co = (100.000 amu total protein) / (0.870 amu Co) = 698881.25 amu

rounded to 3 significant figures:

We get,

69,900 amu

0.870% Cobalt

Ratio of cobalt can be written as:

0.870 amu Co : 100.000 amu (total protein)

Therefore,

58.6 amu Co = (100.000 amu total protein) / (0.870 amu Co) = 698881.25 amu

rounded the figure, we get

69999 amu