Question

A mole of atoms is $6.02\times {10}^{23}$ atoms. To the nearest order of magnitude, how many moles of atoms are in a larger domestic cat? The masses of a hydrogen atom, an oxygen atom, and a carbon atom are $1.0u,16u$, and $12u$, respectively.

Answer 1

as we know,

If we estimate the "typical" large domestic cat mass as $10kg$, and the "typical" atom (in the cat) as $10u\sim 2\times {10}^{-26}kg$, then there are roughly $\left(10kg\right)/(2\times {10}^{-26}kg)\sim 5\times {10}^{26}$ atoms. This is close to being a factor of a thousand greater than Avogadro's number. Thus this is roughly a kilomole of atoms.