Find the Density at STP Be

To find the mass of ${\displaystyle 1}$ mole of ${\displaystyle Be}$ look up the atomic mass of each element and multiply it by the number of atoms contained in each element in the molecule.

mass of ${\displaystyle 1}$ mole of ${\displaystyle Be}$${\displaystyle =}$${\displaystyle \left(\text{mass of Be}\right)}$

Fill in the atomic masses from the periodic table.

mass of ${\displaystyle 1}$ mole of ${\displaystyle Be}$${\displaystyle =}$${\displaystyle \left(9.01000022\right)}$

Remove parentheses.

mass of ${\displaystyle 1}$ mole of ${\displaystyle Be=9.01000022g}$

One mole of any gas occupies ${\displaystyle 22.4L}$ at STP (standard temperature and pressure).

Density is mass over volume.

Factor ${\displaystyle 9.01000022}$ out of ${\displaystyle 9.01000022g}$.

Factor ${\displaystyle 22.4}$ out of ${\displaystyle 22.4L}$.

Separate fractions.

Divide ${\displaystyle 9.01000022}$ by ${\displaystyle 22.4}$.