Solubility is determined by finding the maximum amount of a solute that dissolves in a given amount of solvent at a specific temperature to create a saturated solution. Here's how to find solubility:
Defining Solubility
Solubility is specifically defined as the number of grams of solute needed to saturate 100g of solvent at a given temperature. This definition is crucial for accurate measurement and comparison.
Steps to Determine Solubility
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Prepare a Solution: Start by adding a known amount of solute to a known amount of solvent.
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Mix Thoroughly: Ensure the solution is well-mixed, often with stirring or shaking.
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Add Solute Gradually: Continue adding more solute in small increments, ensuring it dissolves completely before adding more.
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Reach Saturation: Keep adding solute until no more dissolves, and some solid solute remains undissolved at the bottom of the container. This indicates the solution is saturated.
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Determine the Mass: Carefully measure the mass of the solute that has dissolved.
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Calculate Solubility: Using the reference formula, solubility can be calculated by dividing the weight of the solute by the weight of the solvent and multiplying by 100.
- Solubility = (Weight of solute (g) / Weight of solvent (g)) * 100
- Solubility = (b/a) 100* where b is the weight of the solute and a is the weight of the solvent.
Example Calculation
Let's say you dissolve 25g of sugar in 100g of water at a certain temperature until the solution is saturated. Then the solubility is calculated as follows:
Solubility= (25g / 100g) * 100 = 25g of sugar per 100g of water
Factors Affecting Solubility
- Temperature: Solubility usually increases with temperature for solids in liquids, but the opposite can be true for gases in liquids.
- Pressure: Primarily affects the solubility of gases; higher pressure typically increases gas solubility.
- Nature of Solute and Solvent: "Like dissolves like" - polar solutes dissolve in polar solvents, and nonpolar solutes dissolve in nonpolar solvents.
Tools and Techniques
- Laboratory Balance: Accurate weighing of solute and solvent.
- Thermometer: Maintaining and recording temperature.
- Stirring Equipment: Ensuring uniform dissolution.
- Filtration: Separating undissolved solute if needed.
