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The atomic mass of iron is 55.85, and oxygen is 16.0. What is the mass of 6.02 × 1023 molecules of Fe2O3?
A. 71.85 g

B. 143.7 g

C. 159.7 g

D. 199.55 g

E. 215.55 g

Respuesta :

Willchemistry
molar mass Fe2O3 = 55.85 x 2 + 16.0 x 3 => 159.7 g/mol

159.7 g ---------------- 6.02x10²³ molecules
( mass ) ------------- 6.02 x 10²³ molecules

mass = (6.02x10²³ ) x 159.7 / 6.02x10²³

mass = 9.61x10²⁵ / 6.02x10²³

 = 159.7 g

answer C

hope this helps!
As there are two atoms of Fe and three atoms of O in the molecule of Fe2O3:
So,
Multiplying no of atoms with the molar mass ,
55.85 *2 + 3* 16 = 159.7g
So according to above explanation,
C. 159.7 g ,is the correct answer.