Final answer:
The solubility of 64 at 70°C for ammonium chloride indicates that at this temperature, 64 grams of ammonium chloride can dissolve in 100 grams of water. This temperature-dependent solubility is useful for procedures like fractional crystallization. Plus, understanding solubility aids in calculating molarity for concentration analysis.
Step-by-step explanation:
When the solubility of ammonium chloride is said to be 64 at 70°C, it means that 64 grams of ammonium chloride can be dissolved in 100 grams of water at that temperature. Solubility often changes with temperature, as substances like ammonium chloride become more soluble in water as the temperature increases. This property can be used in techniques like fractional crystallization to separate compounds based on their differing solubilities at various temperatures.
For instance, a chemist could separate a mixture of sodium acetate and KBr by dissolving them in water at a high temperature and then cooling the solution, causing the less soluble compound to crystallize and be filtered out. Moreover, the molarity of a solution, which is the moles of solute per liter of solution, can be calculated once you have the mass of the solute in grams. This allows for quantitative analysis in the lab, such as determining concentration for various experiments or industrial processes.