Question

How many molecules of sulfur trioxide are in 78.0 grams?

(A) 7.33 x 10^23
(B) 5.87 x 10^23
(C) 3.76 x 10^27
(D) 0.974
(E) none of the above

Answer 1

Answer:

b) 5.87 E23 molecules

Explanation:

∴ mm SO3 = 80.066 g/mol

⇒ molecules SO3 = (78.0 g)(mol/80.066 g)(6.022 E23 molec/mol)

⇒ molec SO3 = 5.866 E23 molecules SO3