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If the solubility of a particular solute is 10 g/100 g H2O at 20 oC, which of the following would represent a supersaturated solution of that solute: a) 9 g/100 g H2O at 20 oC, or b) 11 g/100 g H2O at 20 oC.

ok im still lost...??

Let me give you another problem and we can walk through it.

Suppose we have a solution in which the solubility of compound A is 15 g A/100 g H2O. What does that mean? It simply means that compound A can dissolve up to 15 g in 100 g H2O.
So if we have 10 g A/100 g H2O it must not be saturated (because it can hold more). Anything LESS THAN 10 will be unsaturated because it can hold more. Anything that show 10 g A/100 g H2O will be saturated (because that's all it can hold). Anything MORE THAN 10 must be supersaturated (because it is MORE than it can normally dissolve. [Note: Students often ask me, "If it can't hold anymore than 10, how can it hold more than 10 and be supersaturated. The answers is that supersaturation occurs under some conditions so we have unsaturated solutions (less than the solvent can dissolve), saturated (the amount that the solvent can dissolve) and supersaturated (more than the solvent can hold under normal conditions.) So which is your solution. Is it more than 10 or less than 10.

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And more than 10 g is supersaturated.

To determine whether a solution is supersaturated, we need to compare the amount of solute present in the solution to the solubility limit at a given temperature.

In this case, we are given that the solubility of the solute is 10 g/100 g H2O at 20 oC. This means that at 20 oC, a maximum of 10 grams of the solute can dissolve in 100 grams of water.

Now let's analyze the options:
a) 9 g/100 g H2O at 20 oC: This option is below the solubility limit of 10 g/100 g H2O, so it is not supersaturated.
b) 11 g/100 g H2O at 20 oC: This option is above the solubility limit of 10 g/100 g H2O, indicating that more solute is present in the solution than can normally dissolve. Therefore, this option represents a supersaturated solution.

So, the correct answer is b) 11 g/100 g H2O at 20 oC.

A supersaturated solution is one that is defined as having MORE of the solute than it can hold normally. Which of the two has more than 10 g/100 g H2O.