Final answer:
An unsaturated solution is one that contains less than the maximum amount of solute that can be dissolved in the given solvent at a particular temperature. Solubility is measured as grams per 100 g of solvent and it changes with temperature. Solubility curves help determine whether a solution is saturated or unsaturated by comparing the amount of solute added to the solubility at that temperature.
Step-by-step explanation:
The term unsaturated solution refers to a solution that contains less than the maximum amount of solute that can be dissolved in a given amount of solvent at a particular temperature. For instance, when 30.0 g of NaCl is added to 100 mL of water at 40°C and it all dissolves, we have an unsaturated solution. However, if you increase the amount to 40.0 g of NaCl, only 36.0 g will dissolve at room temperature and 4.0 g will remain undissolved, creating a saturated solution.
Solubility is often expressed as the grams of solute per 100 g of solvent and it varies with temperature. For example, the solubility of sodium chloride (NaCl) in water is 36.0 g per 100 g water at 20°C. If a student has dissolved 80 grams of a salt in 100 grams of water at 40°C and the solution is unsaturated, this indicates that the solubility of the salt at that temperature is higher than 80 g per 100 g water.
Solubility curves can inform us about whether a given solution is saturated or unsaturated at a specific temperature. Using these curves, we can see that if a solute's solubility at a certain temperature is less than the amount added, any excess will not dissolve and the solution will be saturated. Conversely, if the solubility is higher than the amount added, the solution will remain unsaturated.