Regents Chemistry Exam June 2024 Question 38
38 Based on Table G, which combination of solute and solvent will form a saturated solution when thoroughly mixed at 20.°C?
(1) 15 grams KClO3 in 100. grams H2O
(2) 20. grams KCl in 100. grams H2O
(3) 30. grams NaCl in 100. grams H2O
(4) 35 grams KI in 100. grams H2O
Solution:
Table G provides solubility guidelines for various substances in 100 grams of water. Notice, that the solubility changes with temperature (x axis).
Let's take a look at answer choice 1 for example. Let's say we have 15 grams of KClO3 dissolved in 100 grams of water at 20 °C. We can see that this point is above the curve shown for KClO3. This would be a supersaturated solution = more than the maximum amount of solute got dissolved).
If we are on the solubility line, then the solution is saturated = maximum amount of solute has been dissolved. If we are below the solubility line, then we have a unsaturated solution = more solute can be still dissolved.
We need to find the point for each answer choice and compare them.
The answer for this question is choice 1 according to the scoring guide.
If you check the rest of the answer choices, they will all be below their saturation limit (unsaturated).
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