## Thinking Mathematically (6th Edition)

The mass of 80,000 hydrogen atoms in scientific notation is $1.336\times {{10}^{-19}}$gram.
It is provided that the mass of one hydrogen atom is $1.67\times {{10}^{-24}}\text{ gram}$and it is already in scientific notation. Write 80,000 Hydrogen atoms in scientific notation as follows: $80,000=8.0\times {{10}^{4}}$ Now, Mass of 80,000 Hydrogen atom is: \begin{align} & 8.0\times {{10}^{4}}\times 1.67\times {{10}^{-24}}=\left( 8.0\times 1.67 \right)\times \left( {{10}^{4-24}} \right) \\ & =13.36\times {{10}^{-20}} \\ & =1.336\times {{10}^{-19}}\text{ gram} \end{align} Hence, the mass of 80,000 hydrogen atoms in scientific notation is $1.336\times {{10}^{-19}}$gram.