Calculate the mass in grams of each elemental sample.
(a) 1.32 × 1020uranium atoms
(b) 2.55 × 1022zinc atoms
(c) 4.11 × 1023lead atoms
(d) 6.59 × 1024silicon atoms
Here, we are going to calculate the mass in grams of each of the given elemental sample.
One mole of any species is that quantity in number having a mass equal to its atomic or molecular mass in grams.
The number of particles (atoms, molecules or ions) present in 1 mole of any substance is fixed, with a value of 6.022 × 1023. This is an experimentally obtained value. This number is called the Avogadro Constant or Avogadro Number.
Therefore, 1 mole = molar mass
1 mole = Avogadro number of particles
Combining the two statements, we get,
Mass of Avogadro’s number of particles = Molar mass
Therefore, mass of given number of particles = (Molar mass / Avogadro's number) x given number of particles
The mass of given elemental sample = (given number of particles/Avogadro's number) x molar mass