How many gram atoms are present in 4000 amu of calcium ? 

Explanation

4000 amu of `Ca=40xx10^(2)xx1.66xx10^(-24)g`
One gram atom of Ca = 40 g
Number of gram atoms of Ca in 4000 amu
`=(40 xx 1.66 xx 102 xx 10^(-24))/(40)=1.66xx10^(-22) = 1.66 xx 10^(-22)`