Question

What is the Wt% of SiO2 in augite? (Ca, Fe, Mg, Na)(Mg,Fe,Al) (Si,Al)2 O6

Answer 1

Answer:

The weight% of $SiO_2$ in augite is 13.16 %.

Explanation:

Atomic mass of calcium = 40 g/mol

Atomic mass of iron = 56 g/mol

Atomic mass of magnesium = 24 g/mol

Atomic mass of sodium = 23 g/mol

Atomic mass of aluminum = 27 g/mol

Atomic mass of silicon = 28 g/mol

Atomic mass of oxygen = 16 g/mol

Mass of $SiO_2=28 g/mol+ 2\time 16 g/mol=60 g/mol$

Molar mass of the augite $(Ca, Fe, Mg, Na)(Mg,Fe,Al)(Si,Al)_2 O_6$ = M

$M=40 g/mol+2\times 56 g/mol+2\times 24 g/mol+23 g/mol+3\times 27 g/mol+2\times 28 g/mol+6\times 16 g/mol=456 g/mol$

Weight% of $SiO_2$ in augite:

$w\%=\frac{60 g/mol}{456 g/mol}\times 100=13.16\%$