0.18 grams of glucose contains how …

So, glucose's molecular formula is C₆H₁₂O₆, which means that every molecule of glucose contains Six carbon atoms ,Twelve hydrogen atoms, Six oxygen atoms.

Molar mass of C = 12 g mol^-1

Molar mass of H = 1 g mol^-1 

Molar mass of O = 12 g mol^-1 

There fore,

Molar mass of C₆H₁₂O₆=(6x12) + (12x1) + (6x16) = 72 + 12 + 96 = 180 g mol^-1

Now we can calculate the number of moles of glucose as follows: 

The number of moles of glucoses n  = w/M , where w is weight in gram and M is molar mass.

=> 0.18/180 = 10^-3 moles

It is also possible to get the number of atoms in the given sample by multiplying the number of moles with Avogadro number, N_A 

Thus

the number of atoms = n.N_A, Where N_A = 6.022 x 10²³

In above glucose sample, 

the no. of glucose atomes  = 10^-3 x 6.022 x 10²³ = 6.022 x 10²⁰