Question

Sulfur trioxide reacts with water to form sulfuric acid according to the following reaction:

SO3 + H2O → H2SO4

Sulfuric acid (H2SO4) has the atomic mass of 98 amu, hydrogen (H) has an atomic mass of 1 amu, and oxygen (O) has the atomic mass of 16 amu. Use this information to figure out the atomic mass of sulfur (S) and then use that number to calculate the atomic mass of sulfur trioxide (SO3).

(1 point)
Responses

116 amu
116 amu

48 amu
48 amu

32 amu
32 amu

80 amu
80 amu

Answer 1

H2SO4 mass = 98 = mass(S) + 2(1) + 4(16) = mass(S) + 2 + 64 = mass(S) + 66
So mass(S) = 98 − 66 = 32 amu.
Mass(SO3) = 32 + 3(16) = 32 + 48 = 80 amu.

Answers: S = 32 amu; SO3 = 80 amu.