If a solution is made by dissolving 15g of each solid in the same 100g of water at 70 degrees and the solution is cooled to 20 degrees, crystals are observed.. Which solid crystallises and explain in reference to both solids
Do you expect us to be clairvoyant? What solids? What are the solubilities? Etc, The solid crystallizing first will be the less soluble one at 20 C.
why will the least soluble solution crystallise first?
To determine which solid crystallizes when the solution is cooled, we need to consider the concept of solubility and solubility curves.
Solubility refers to the maximum amount of solute that can be dissolved in a given solvent under specific conditions, such as temperature. Solubility curves depict the relationship between solubility and temperature for a particular solute and solvent combination.
In this case, it is important to know the solubility of both solids at different temperatures to determine which solid will crystallize. If one solid is more soluble than the other, it will remain dissolved even at lower temperatures.
To find the solubility of each solid at different temperatures, we would refer to a solubility curve specific for each solid in water. These solubility curves can be found in reference books or online resources.
Once you have access to the solubility curves, you can compare the solubilities of the two solids at both 70 degrees and 20 degrees. If one solid's solubility decreases significantly with temperature, while the other solid's solubility remains relatively stable or decreases at a slower rate, then the solid with the lower solubility at the colder temperature is more likely to crystallize.
By analyzing the solubility curves and comparing the solubilities at both temperatures, you can determine which solid will crystallize when the solution is cooled from 70 degrees to 20 degrees.