Question

Which of the following will affect the total amount of solute that can dissolve in a given amount of solvent? a. The solution is stirred. b. The solute is ground to fine particles before dissolving. c. The temperature changes.

Short answer

Changing the temperature (option c) will affect the total amount of solute that can dissolve in a given amount of solvent. This is because, for most solid solutes, solubility increases with increasing temperature, while solubility of some gases in liquids decreases. Stirring (option a) and grinding the solute to fine particles (option b) will only increase the rate at which solute dissolves, but do not affect the maximum solubility.

Step-by-step solution

Understanding solubility

Solubility is the maximum amount of solute that can be dissolved in a specific quantity of solvent at a given temperature. Factors influencing solubility include temperature, pressure (for gases), and the nature of the solute and solvent. Stirring and grinding are related to the rate at which the solute dissolves, not the maximum amount, while temperature directly influences the solubility of the solute.

Impact of stirring the solution

Stirring a solution helps mix the solute with the solvent, which can make the solute dissolve faster. However, stirring the solution does not affect the maximum amount of solute that can dissolve. So, option a is not a factor that affects solubility.

Impact of grinding the solute

Grinding a solute to fine particles before dissolving increases its surface area, making it dissolve faster in the solvent. However, just like stirring, the grinding does not affect the maximum amount of solute that can dissolve. So, option b is also not a factor that affects solubility.

Impact of temperature changes

Temperature is a factor that directly influences solubility. For most solid solutes, solubility increases with increasing temperature. This is because, at higher temperatures, the particles in the solvent have more kinetic energy, which causes more collisions with the solute particles, allowing more solute to dissolve. Similarly, the solubility of some gases in liquids decreases with increasing temperature, as gases are less likely to dissolve in the liquid. Therefore, option c is the factor that affects solubility.

Conclusion

Based on the analysis of each option, it is clear that changing the temperature (option c) will affect the total amount of solute that can dissolve in a given amount of solvent. Stirring and grinding to fine particles may increase the rate at which solute dissolves, but they do not affect the maximum solubility.

Key concepts

Factors Influencing Solubility

Understanding the factors that influence solubility is vital for mastering chemistry concepts related to solutions. Solubility refers to the ability of a solute to dissolve in a solvent; it is not a fixed property but can change under different conditions. One of the main factors affecting solubility is the nature of the solute and solvent. Polar solvents, like water, are better at dissolving polar substances, due to the mutual attraction of their molecules. Conversely, non-polar solvents dissolve non-polar substances well.

Another significant factor is pressure, especially relevant for gases. Generally, the solubility of gases in liquids goes up with an increase in pressure, in accordance with Henry's Law. Lastly, structures and interaction forces in substances, such as hydrogen bonding, van der Waals forces, and ionic bonds, also play important roles in determining solubility.

• Polar solutes tend to dissolve well in polar solvents due to similar intermolecular forces.
• Non-polar solutes dissolve better in non-polar solvents, following the 'like dissolves like' principle.
• Increasing pressure usually improves the solubility of gases in liquids.
• Molecular interactions and structures can greatly influence solubility rates.

Temperature's Effect on Solubility

Temperature is a crucial factor that can significantly alter the solubility of a solute. For many solids, solubility increases as temperature rises. This is usually because higher temperatures provide more kinetic energy to the molecules, leading to increased molecular interactions and, consequently, greater solubility. When a solution is heated, solvent particles move more vigorously, disrupting the solid solute's crystalline lattice more efficiently and allowing the molecules or ions to mix into the solution.

However, for gases in liquids, the situation is often the reverse; their solubility decreases with an increase in temperature. As the temperature rises, gas molecules gain kinetic energy, making them more likely to escape from the liquid phase into the gas phase. This phenomenon is the reason why a warm soda is fizzier than a cold one; more CO₂ escapes as the temperature goes up.

• For solid solutes, higher temperatures can increase solubility.
• For gaseous solutes, solubility often decreases with higher temperatures.
• The dissolving process is endothermic for solids, absorbing heat and aiding solubility.
• For gases, solubility in liquids decreases as temperature increases due to the exothermic nature of the process.

Solubility and Solution Rate

While solubility defines how much solute can dissolve in a given solvent at equilibrium, the solution rate describes how quickly this dissolving occurs. These two concepts are related but distinct. Factors like stirring and grinding impact the rate at which a solution occurs but do not affect the total amount of solute that a solvent can hold at equilibrium.

Stirring a solution speeds up the dissolution process by distributing the solute particles more evenly and bringing fresh solvent into contact with the solute. Grinding the solute into finer particles increases the surface area available, allowing more solvent to simultaneously interact with more solute particles, finding the process faster. Temperature can also affect the solution rate; for most solids, an increase in temperature quickens the dissolving process, while for gases, a decrease in temperature often has the same effect.

• Stirring and increasing surface area by grinding can accelerate the solution rate.
• The solution rate must not be confused with solubility, which is the maximum solute that dissolves at equilibrium.
• Temperature is influential both for solubility and solution rate, albeit in different ways for solid and gaseous solutes.