Question

${10}^{-x}$ moles of cobalt atoms are there in $6.022\times {10}^9$ $Co$ atoms. The value of $x$ is:

Answer 1

As we know, one mole of every substance have $N_o$ entities. So, one mole of Co have $N_o$ atoms of Co.
Therefore, moles of Co $=6.022\times {10}^9/6.022\times {10}^{23}={10}^{-14}$