Question

How many moles are in 3.4 x 10-7 grams of silicon dioxide?

Answer 1

Answer:

$1.13X10^{-8}mol$

Explanation:

The molecular formula of silicon dioxide is : SiO₂

There are two oxygen atoms and one silicon atom.

The atomic mass of oxygen =  16 g/mol

The atomic mass of silicon = 28 g/mol

So the molar mass of silicon dioxide = 28 + 2(16) = 60 g/mol

Given the mass of silicon dioxide = $3.4X10^{-7}$

$moles=\frac{mass}{molarmass}=\frac{3.4X10^{-7}}{30}=1.13X10^{-8}mol$

Answer 2

Molar mass is  28+32 = 60
So take 3.4 x 10^-7/60 and get about 5.7 x 10^-9