Determine the number of formula units of cr(clo2)3 and moles of oxygen contained in 6.85 moles of cr(clo2)3

The formula  units  of Cr(ClO2)3  that  are in 6.85  moles of Cr(Clo203  is  4.1237 x10^24  formula units

 calculation

  the formula units are  calculated using of Avogadro's  law  constant

that is   according  to Avogadro's law   1  mole = 6.02 x10 ^23  formula units

                                                             6.85 moles= ?  formula units

by  cross  multiplication.

 = ( 6.85 moles   x 6.02  x10^23  formula units )  / 1 mole  = 4.1237  x 10 ^24  formula units

 calculation

moles   of  oxygen = number of oxygen atom in  Cr(ClO2)3  x   6.85(moles of  Cr(ClO2)3

calculate the number of   oxygen atoms that  are in Cr(ClO2)3

that is  2 x 3 = 6 atoms of Oxygen.

moles is therefore =  6  x 6.85 moles= 41.1 moles