You can determine solubility by measuring the amount of substance that dissolves in a specific volume of solvent, using a threshold to classify it.
According to chemical definitions, a substance's solubility is determined by how much of it can dissolve in a given amount of solvent under specific conditions (like temperature and pressure). Based on the provided reference, a common method for classification involves observing the amount that dissolves in 100 mL of solvent.
Key Solubility Classifications
The reference provides a specific quantitative measure to classify substances as soluble or insoluble:
- Soluble: A substance is considered soluble if more than 0.1 g of that substance dissolves in 100 mL solvent.
- Insoluble or Sparingly Soluble: If less than 0.1 g dissolves in 100 mL solvent, the substance is classified as insoluble or, more precisely, sparingly soluble.
This threshold of 0.1 g per 100 mL serves as a practical dividing line for quick determination of solubility.
How the 0.1 g / 100 mL Rule Works
To apply this rule, you would typically:
- Take a defined volume of solvent (e.g., 100 mL).
- Gradually add the substance you are testing while stirring.
- Observe how much of the substance dissolves.
- Once no more substance dissolves (the solution is saturated) or if you have added a significant amount with very little dissolving, measure or estimate the total mass of the substance that successfully dissolved in the solvent.
- Compare the dissolved mass to the 0.1 g threshold.
Here's a simple summary based on the reference:
| Solubility Classification | Amount Dissolved in 100 mL Solvent |
|---|---|
| Soluble | More than 0.1 g |
| Insoluble / Sparingly Soluble | Less than 0.1 g |
Practical Considerations
While the 0.1 g per 100 mL rule provides a clear classification based on the reference, it's important to remember that solubility is influenced by various factors:
- Temperature: Solubility often increases with temperature, especially for solids in liquids.
- Pressure: Pressure significantly affects the solubility of gases in liquids.
- Nature of Solute and Solvent: "Like dissolves like" - polar solvents tend to dissolve polar solutes, and nonpolar solvents dissolve nonpolar solutes.
- Presence of other substances: Other dissolved substances can affect solubility.
Therefore, for precise scientific or industrial applications, solubility is typically determined and reported with specific conditions (temperature, pressure, etc.). However, for a general classification using the provided reference, the 0.1 g/100 mL guideline is the key determinant.
