How many helium atoms are in a helium blimp containing 494 kg of helium?
Step 1: calculate how the number of moles using the molar mass.
The molar mass of helium =
This means that 1 mole of helium atoms weighs 4 gram.
In this case you have
Step 2 : calculate the number of atoms using Avogadro's constant.
Avogadro's constant states that there are
How many atoms are in 123.500 moles?