Final answer:
The question asks about the amount of water needed to dissolve 10 grams of KNO3 at 60°C, based on solubility curves. If 107 g of KNO3 is soluble in 100 g of water at this temperature, then approximately 9.35 g of water would be needed to dissolve 10 g of KNO3. None of the options provided exactly match this calculated value, but all given options are sufficient to dissolve 10 grams of KNO3.
Step-by-step explanation:
The student's question is about the solubility of potassium nitrate (KNO3) in water at a specific temperature. Solubility curves can be used to determine the mass of solute that can be dissolved in a specific mass of solvent at various temperatures. In our example, according to a solubility curve of KNO3, we know the solubility at 60°C is about 107 grams of KNO3 per 100 grams of water.
To find the amount of water needed to dissolve 10 grams of KNO3 at 60°C, we need to set up a proportion based on the solubility curve. If 107 grams of KNO3 dissolve in 100 grams of water, then 10 grams would dissolve in X grams of water:
107 g KNO3 / 100 g H2O = 10 g KNO3 / X g H2O
Solving for X:
X = (10 g KNO3 × 100 g H2O) / 107 g KNO3
X ≈ 9.35 g H2O
Since the closest answer choice without going under this calculated value is 10 grams of potassium nitrate in 10 grams of water, none of the given options (A-D) are correct. However, if the question might have a typo and was intended to ask for how much KNO3 can be dissolved in a given amount of water at 60°C, then the correct answer would be that you can dissolve 10 grams of KNO3 in about 9.35 grams of water, which is less than 100 grams (option A), 90 grams (option B), 50 grams (option C), and 110 grams (option D) of water respectively. Since the solubility allows for approx. 107 grams in 100 grams of water, any of these amounts are more than enough to dissolve 10 grams of KNO3.