To calculate the number of atoms of Cr, we first find the number of moles per unit of cubic centimeter of Cr. Then, use avogadros number for the number of atoms. Calculations are as follows:
1 cm^3 (7.15 g/cm^3) (1 mol / 51.996 g Cr) = 0.14 mol Cr
0.14 mol Cr ( 6.022 x 10^23 atoms Cr / 1 mol Cr ) = 8.28 x 10^22 atoms Cr
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BiO₃⁻ → Bi³⁺
+5 +3
Balance oxidation state:
BiO₃⁻ + 2 e⁻ → Bi³⁺
Balancing oxygen by adding water and balance H
BiO₃⁻ + 6 H⁺ + 2 e⁻ → Bi³⁺ + 3 H₂O
balance charge:
BiO₃⁻ + 6 H⁺ + 2 e⁻ → Bi³⁺ + 3 H₂O
+ 3 + 3
Final:
BiO₃⁻ + 6 H⁺ + 2 e⁻ → Bi³⁺ + 3 H₂O
