Question

How many oxygen atoms are in 1.60 g

g of quartz?

number of O atoms =

Answer 1

M(SiO₂) = 60.08 g/mol

n(SiO₂) $= \frac{m}{M} = \frac{1.60}{60.08}=0.0266 \;mol$

Number of molecules:

N(SiO₂) $= 0.0266 \times 6.02 \times 10^{23}=1.603 \times 10^{22}$

Each SiO₂ molecule contains 2 oxygen atoms

number of O atoms $= 2 \times 1.603 \times 10^{22} = 3.206 \times 10^{22}$