Question

Indicate the concentration of each ion present in the solution formed by mixing the following15.0 mL of 0.304 M Na2SO4 and 34.6 mL of 0.200 M KCLNa+K+SO4^2-CL-

Answer 1

1) Concentration of Na+

1.1- List the known quantities.

Molarity: 0.304 M Na2SO4.

Volume: 15.0 mL

M= mol/L

1.2- Set the equation

The ion-molecule ratio is 2 Na atoms: 1 molecule Na2SO4.

`M_(Na^+)=0.304\text{ }\frac{mol\text{ }Na_2SO_4}{L}*\frac{2\text{ }mol\text{ }Na^+}{1\text{ }mol\text{ }Na_2SO_4}=0.608\frac{mol\text{ }Na^+}{L}`

The concentration of Na+ is 0.608 M.

2) Concentration of SO4 (2-)

2.1- List the known quantities.

Molarity: 0.304 M Na2SO4.

Volume: 15.0 mL

M= mol/L

2.2- Set the equation

The ion-molecule ratio is 1 SO4 (2-): 1 molecule Na2SO4.

`M_(SO_4^(2-))=0.304\text{ }\frac{mol\text{ }Na_2SO_4}{L}*\frac{1\text{ }mol\text{ }SO_4^(2-)}{1\text{ }mol\text{ }Na_2SO_4}=0.304\frac{mol\text{ SO}_4^(2-)}{L}`

The concentration of SO4 (2-) is 0.304 M.

3) Concentration of K+

3.1- List the known quantities.

Molarity: 0.200 M KCl.

Volume: 34.6 mL

M= mol/L

3.2- Set the equation

The ion-molecule ratio is 1 K+: 1 molecule KCl.

`M_(K^+)=0.200\frac{mol\text{ }KCl}{L}*\frac{1\text{ }mol\text{ }K^+}{1\text{ }mol\text{ }KCl}=0.200\text{ }\frac{mol\text{ }K^+}{L}\text{ }`

The concentration of K+ is 0.200 M.

4) Concentration of Cl-

4.1- List the known quantities.

Molarity: 0.200 M KCl.

Volume: 34.6 mL

M= mol/L

4.2- Set the equation

The ion-molecule ratio is 1 Cl-: 1 molecule KCl.

`M_(Cl^-)=0.200\frac{mol\text{ }KCl}{L}*\frac{1\text{ }mol\text{ }Cl^-}{1\text{ }mol\text{ }KCl}=0.200\text{ }\frac{mol\text{ }Cl^-}{L}`

The concentration of Cl- is 0.200 M.

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