At 88 °C the solubility of KNO₃ is 88 g per 100 g of water. Would a solution that has a molarity of 0.990 M KNO₃ and a density of 0.988 g/mL be considered unsaturated, saturated, or supersaturated?

• A. Unsaturated
• B. Saturated
• C. Supersaturated
• D. cannot determine

Answer: (A)

Verified step by step guidance

1. First, calculate the molar mass of KNO3. The molar mass is the sum of the atomic masses of potassium (K), nitrogen (N), and three oxygen (O) atoms. Use the periodic table to find these values.
2. Convert the solubility of KNO3 from grams per 100 grams of water to molarity (moles per liter). Start by converting 88 g of KNO3 to moles using its molar mass.
3. Next, convert 100 g of water to liters. Since the density of water is approximately 1 g/mL, 100 g of water is equivalent to 100 mL or 0.1 L.
4. Calculate the molarity of the saturated solution by dividing the moles of KNO3 by the volume of water in liters.
5. Compare the calculated molarity of the saturated solution to the given molarity of 0.990 M. If the given molarity is less than the calculated molarity, the solution is unsaturated. If it is equal, the solution is saturated. If it is greater, the solution is supersaturated.