Question

Find the mass of 0.235 moles of SiO2? (NOTE: use correct significant figures!)

Answer 1

Answer: 14.1g

Explanation:

Given that,

number of moles of SiO2 = 0.235 moles

Mass in grams = Z (let unknown value be Z)

Molar mass of SiO2 = ?

To get the molar mass of SiO2, use the atomic mass

Silicon = 28g;

Oxygen = 16g

i.e Molar mass of SiO2 = 28g + (16g x 2)

= 28g + 32g

= 60g/mol

Now, apply the formula

Number of moles = Mass / molar mass

0.235 moles = Z / 60g/mol

Z = 0.235 moles x 60g/mol

Z = 14.1 g

Thus, the mass of SiO2 is 14.1 grams.