Answer to Question #287203 in Chemistry for Gab

Question

Quartz, SiO2, is the most abundant mineral found at Earth's surface and its unique properties make it one of the most useful natural substances. Quartz is a chemical compound consisting of one part silicon and two parts oxygen, what is its percentage composition?​

Answer 1

Solution:

Quartz = SiO₂

Relative atomic mass (Ar) of silicon (Si) = 28.086

Ar(O) = 15.999

Molar mass of SiO₂ = Ar(Si) + 2 × Ar(O) = 28.086 + 2 × 15.999 = 60.084

Hence,

%Si = [Ar(Si) / M(SiO₂)] × 100%

%Si = (28.086 / 60.084) × 100% = 46.74%

%silicon = 46.74%

%O = 100% - %Si = 100% - 46.74% = 53.26%

%oxygen = 53.26%

Answer: Quartz (SiO₂) has a percent composition of 53.26 percent oxygen and 46.74 percent silicon.