Question

Mass of a calcium atom is 40.0u express in kg

Answer 1

1u = 1.66 * 10^-27

40.0u = 6.64 * 10^-26

hope it helps!!

Answer 2

Given mass of Calcium atom as $40.0 \;u$.

We know one atomic mass unit $1\;u=1.66054*10^{-27}\;kg$.

The mass of Calcium atom in kg is

$(40\;u)1.66054*10^{-27}\;kg/u=66.4216*10^{-27}\;kg=6.64216*10^{-26}\;kg$