The solubility of barium nitrate is 9.02 g/100 g H2O at 20°C. A 15.2 g sample of barium nitrate is added to 200.0 g of water at 20°C. Is the solution saturated, unsaturated, or supersaturated?

The solution is unsaturated.

Explanation:

Saturated solutions are those solutions with the maximum amount of solute completely dissolved by the solvent. This indicates that although more solute is added, it does not dissolve. In this case the amount of solute is equal to the solubility coefficient.

The supersaturated solution  is one in which the amount of solute exceeds the solubility of the solvent, that is, it has a greater amount of dissolved solute than that which it admits at that temperature. In this case a solution contains solute above the solubility coefficient.

A solution is considered to be unsaturated if the mass of dissolved solute is less than that corresponding to that of saturation. This indicates that it is possible to add more solute and that it dissolves. In this case the solution contains solute below the solubility coefficient.

The solubility of barium nitrate is 9.02 g/100 g H₂O at 20°C.

A 15.2 g sample of barium nitrate is added to 200.0 g of water at 20°C. This is: 15.2 g /200 g H₂O.  Dividing by two you get: 7.6 g /100 g H₂O

Comparing with the solubility of barium nitrate, you can see that the mass of dissolved solute is less than the corresponding one. This indicates that the solution is unsaturated.

a and b sometimes have a positive value

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