Marble chips are practically insoluble in water. While they are composed primarily of calcium carbonate (CaCO3), a substance that can theoretically dissolve to a minuscule extent, the amount is so small it's considered negligible for most practical purposes.
Understanding Solubility
Solubility refers to the ability of a substance (the solute) to dissolve in a solvent (like water) and form a solution. Calcium carbonate's solubility in pure water is very low, roughly 0.013 g per liter at 25°C.
Why Marble Doesn't Readily Dissolve
- Chemical Composition: Marble is mainly composed of calcium carbonate.
- Low Solubility of Calcium Carbonate: Calcium carbonate has a low intrinsic solubility in water.
- Environmental Factors: While pure water doesn't dissolve much marble, slightly acidic water (due to dissolved carbon dioxide from the air) can increase the dissolution process over long periods. This is the basis of acid rain's effect on marble statues and buildings.
Factors Influencing Dissolution (Minimal Impact on Practical Solubility)
While marble is practically insoluble, these factors can slightly affect the dissolution rate, although the changes are generally insignificant in everyday scenarios:
- Temperature: Higher temperatures can slightly increase solubility, but the effect is minimal for calcium carbonate within normal temperature ranges.
- pH: Acidic conditions (low pH) significantly increase the solubility of calcium carbonate. This is because the acid reacts with the carbonate ions, shifting the equilibrium towards dissolution.
- Presence of Other Ions: The presence of certain ions in the water can also influence solubility, though these effects are complex and often specific to the ions involved.
Practical Implications
For most applications, such as using marble chips in landscaping or aquariums, the extremely low solubility means they will not noticeably dissolve. However, prolonged exposure to acidic environments (like acidic soil or water) can lead to gradual erosion over very long periods.
