Question

How many atoms of oxygen are there in 45.67 g of C6H12O6?

Answer 1

Solution.

Calculate molecular mass C6H12O6:

$M=12*6+12+16*6=180$ g/mole.

Calculate amount mole of substance in 45.67 g of C6H12O6:

$\nu=\dfrac{m}{M}=\dfrac{45.67}{180}=0.25$ mole.

1 mole contains number of molecules $N_A=6.02*10^{23}$ molecules, so in 45.67 g C6H12O6 contains number of molecules:

$N=N_A*\nu=6.02*10^{23}*0.25=1.505*10^{23}$molecules.

1 molecule contains 6 atoms of oxygen, so number of atoms:

$N_O=N*6=1.505*10^{23}*6=9.03*10^{23}$ atoms of oxygen.

Answer: $9.03*10^{23}$ atoms of oxygen.