Question

How many molecules are their in 0.325 g of aspirin? ( use formula mass: aspirin, 180,2 amu)

a) 1.09* 10^21 molecules

b) 2.17 *10^21 molecules

C) 1.96 *10^23 molecules

d) 3.91*10^23 molecules

E) 1.85* 10^24 molecules

Answer 1

moles of aspirin = 0.325 g x 1 mol/180.2 g

                          = 1.80 x 10^-3 mol

Molecules of aspirin = 1.80 x 10^-3 mol x ( 6.023 x 10^23 molecules/1 mol)

                                = 1.09*10^21 molecules.

Hence, answer is option a.