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Solubility of Elements and Compounds

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Solubility is a physical property that determines whether an element or compound will dissolve in a solvent to form a solution

Solubility is a measure of how much solute can be dissolved into a solvent before no more can be dissolved at which it reaches the solubility equilibrium. We can practically measure this by putting different masses of a solid into a solute and seeing how much of it will dissolve before no more will.


When a solute has been dissolved to its maximum solubility it is described as a saturated solution. If a substance is described as insoluble then it will not dissolve at all. The substance being dissolved is often called the solute, it can be a solid, liquid or gas. An example of this is sodium chloride, a solid, being dissolved in a solvent such as water. For a gas this could be a gas like carbon dioxide dissolving in water.


Solubility depends on a number of factors, such as pressure, the solvent, the polarity and temperature. We can measure solubility by comparing the volume of solvent it takes to dissolve a mass of solute. For example the ionic compound lead chloride has a solubility if 10.8g/dm3 meaning in 1 litre/1dm3/1000cm3 we can dissolve 10.8g before not more will dissolve. This is compared to sodium hydroxide which has a solubility of 2100g/dm3 which when converted is 2.1kg per dm3 meaning we can dissolve a lot more sodium hydroxide in 1dm3 of water compared to lead chloride.


Solubility can be determined by many different factors. One factor is the intermolecular forces that govern the interactions between the solvent and solute. For example more polar solvents such as water will interact with solutes very differently to a much more polar solvent like dichloromethane. It can also be effected by the presence of other ions as they compete for the interactions of intermolecular forces with the solvent. Temperature also effects solubility. In general the higher the temperature the higher the solubility of the solute.

Terms in section
Solubility

Solubility is a measure of how much of a solute you can put into a solvent before no more will be dissolved

Dissolve

Dissolve is used to describe when a solid is put into a liquid and will form a solution

Solubility equilbrium

Solubility equilibrium is the point at which no more solute can be dissolved into a solvent and it is described as saturated

Saturated

Saturated is term given to a solution that has reached the point at which no more solute can be dissolved in the solvent

Solution

A solution is a term given to the mix of a solute and solvent

Pressure

Pressure is a measure of the force exerted by a liquid or gas on its container

Volume

Volume is a measure of 3 dimensional space that a substance can occupy measured in cm3. Volume is used to measure gases, solids, and liquids.

Intermolecular forces

Intermolecular forces are temporary interactions between ions, atoms or compounds that are not considered to be sharing electrons.

Solvent

A solvent is a liquid substance that can dissolve a solid

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