The minimum temperature required to dissolve 140.0g of KNO3 in 100.0g of water is not given explicitly. However, because 107 g of KNO3 is soluble at 60°C, it would need to be higher than this temperature.
The student is asking about the minimum temperature needed to dissolve a specific amount of potassium nitrate (KNO3) in water.
To determine this, we use solubility curves which indicate how the solubility of a substance varies with temperature.
From the provided information, if we add 80 g of KNO3 to 100 g of water at 30°C, the solubility curve tells us that only about 48 g will dissolve, leaving the rest undissolved.
By this logic, to dissolve 140.0 g of KNO3 in 100.0 g of water, the temperature must be high enough for the solubility of KNO3 at that temperature to be at least 140 g per 100 g of water.
Since we do not have the exact solubility curve provided for KNO3, we cannot give an exact temperature.
However, based on how the solubility of substances generally increases with temperature, we can deduce that the temperature required would be higher than 60°C, as 107 g of KNO3 is soluble at this temperature and we need to dissolve even more.