Question

How many molecules are there in 8.25 moles of CaHia?

Answer 1

The number of molecules : 4.967 x 10²⁴

Further explanation  

A mole is a number of particles(atoms, molecules, ions)  in a substance

This refers to the atomic total of the 12 gr C-12  which is equal to 6.02.10²³, so 1 mole = 6.02.10²³ particles  

Can be formulated :

N = n x No

N = number of particles

n = mol

No = 6.02.10²³ = Avogadro's number

8.25 moles of C₈H₁₈

The number of molecules :

$\tt 8.25\times 6.02\times 10^{23}=4.967\times 10^{24}$