Determine the concentration of no3− in each aqueous solution. (assume complete dissociation of each compound.)
a) 0.30 m kno3
b) 0.30 m ca(no3)2
c) 0.30 m cr(no3)3

A) The concentration of NO₃⁻ is 0.30 M

B) The concentration of NO₃⁻ is 0.60 M

C) The concentration of NO₃⁻ is 0.90 M

Explanation:

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Let´s write the chemical equation for every dissociation reaction:

A) KNO₃ → K⁺ + NO₃⁻

Since 1 mol of KNO₃ produces 1 mol of NO₃⁻, 0.3 mol will produce 0.3 mol NO₃⁻. Then, the concentration of NO₃⁻ will be 0.30 M.

B) Ca(NO₃)₂ → Ca²⁺ + 2NO₃⁻

1 mol of Ca(NO₃)₂ produces 2 mol of NO₃⁻, then, the concentration of NO₃⁻ will be twice the concentration of Ca(NO₃)₂, that is, 0.60 M.

C) Cr(NO₃)₃ → Cr³⁺ + 3NO₃⁻

1 mol of Cr(NO₃)₃ produces 3 mol of NO₃⁻, then, if we have 0.30 mol per liter of Cr(NO₃)₃, we will have 0.90 mol per liter of NO₃⁻

it's c. elements are placed in rows based on how may valencies electrons have.