Stoichiometry (8A. S, 8B. R, 8G. S, 8H. S]:Question 4
What is the mass of 1.204 x1024 particles of Li2O?

                    59.76 grams of Li₂O

Explanation:

To solve this problem we will first calculate the moles of Li₂O.                       One mole of given substance always contains 6.022 × 10²³ particles  which can be atoms, ions, molecules or formula units. This number is also called as Avogadro's Number.

The relation between Moles, Number of Particles and Avogadro's Number is given as,

                         Number of Moles  =  Number of Particles ÷ 6.022 × 10²³

Putting values,

                         Number of Moles  =  1.204 × 10²⁴ Particles ÷ 6.022 × 10²³

                         Number of Moles  =  2.0 Moles

Secondly, we will convert calculated moles to mass using following relationship.

                         Moles  =  Mass  /  M.Mass

Or,

                         Mass  =  Moles  ×  M.Mass

Putting values,

                         Mass  =  2.0 mol × 29.88 g/mol

                         Mass  =  59.76 grams of Li₂O

the answer is b & c i believe : )