8. If 30.0 mL of 12.0 M HCl stock solution is diluted to a volume of 500. mL, what is the molarity of the dilute solution? 15. What is the BPE of a solution of sodium chloride dissolved in acetic acid if the boiling point of the solution is 127.3°C?
16. When a non-ionizing compound is dissolved in phenol the freezing point of the solution is 40.7°C. What is the FPD for this solution?
17. What is the FPD of a solution of C10H8 dissolved in benzene if the freezing point of the solution is -21.0°C? 18. Define solubility:
19. What factor increases the solubility of solid solutes?
20. What factor increases the solubility of gaseous solutes? What factor decreases the solubility of gaseous solutes?
21. What factors increase the rate of dissolving of solid solutes?
22. What is the difference in saturated, unsaturated, and supersaturated solutions.
23. What is the difference between a solution, colloid, and a suspension. What technique can be used to determine if a substance is a solution, colloid, or a suspension?
24. Is making a solution a physical or chemical change? Why?
Answers & Comments
Answer:
20: The solubility of gaseous solutes in a solvent generally increases with increasing pressure. This is described by Henry's law, which states that the solubility of a gas in a liquid is directly proportional to the partial pressure of the gas above the liquid.
On the other hand, the solubility of gaseous solutes typically decreases with increasing temperature. This is because as the temperature of the system increases, the kinetic energy of the gas molecules also increases, and the gas becomes less soluble in the liquid solvent. This is the opposite of the effect of temperature on the solubility of solid solutes, which generally increases with increasing temperature.
Other factors that can affect the solubility of gaseous solutes include the nature of the solvent and the gas, the presence of other solutes or substances in the solution, and the presence of chemical reactions that may occur between the gas and the solvent.
21: Temperature: An increase in temperature usually increases the kinetic energy of the solvent molecules, which allows them to move faster and collide more frequently with the solute particles. This leads to a faster rate of dissolving.
Agitation: Stirring or shaking the solution can help to increase the contact between the solute and solvent, which can lead to a faster rate of dissolving.
Surface area: Breaking up the solute into smaller particles or increasing its surface area can provide more contact points with the solvent, which can also lead to a faster rate of dissolving.
Pressure: In the case of gases dissolving in liquids, an increase in pressure can lead to a higher concentration of gas molecules in the solvent, which can lead to a faster rate of dissolving.
Polarity: Solutes that have polar or ionic properties tend to dissolve more readily in polar solvents, while nonpolar solutes dissolve more easily in nonpolar solvents. Matching the polarity of the solute and solvent can increase the rate of dissolving.
22: A saturated solution is one in which no more solute can be dissolved at a given temperature and pressure. In other words, the solution contains the maximum amount of solute that the solvent can hold. Any additional solute added to the solution will not dissolve and will settle at the bottom of the container.
An unsaturated solution is one in which more solute can be dissolved in the solvent at a given temperature and pressure. The solution contains less solute than it could potentially hold, and additional solute can be added and dissolved until the solution becomes saturated.
A supersaturated solution is one in which more solute has been dissolved than is normally possible at a given temperature and pressure. This is achieved by dissolving the solute in a hot solvent and then slowly cooling the solution. As the solution cools, the solute remains dissolved even though it would normally precipitate out as a solid. Supersaturated solutions are unstable and can easily return to a saturated state if disturbed or if a seed crystal of the solute is introduced to the solution.
23: A solution is a homogeneous mixture of two or more substances, where the solute is uniformly distributed in the solvent. A colloid is a mixture where the size of the particles is larger than in a solution, but smaller than in a suspension. In colloids, the particles do not settle down and remain dispersed throughout the mixture. A suspension is a heterogeneous mixture in which the particles of the solute settle down due to gravity, forming a layer at the bottom of the mixture.
To determine if a substance is a solution, colloid, or a suspension, the Tyndall effect can be used. When a beam of light is passed through a mixture, the Tyndall effect causes the light to scatter due to the presence of larger particles in colloids and suspensions. The scattering effect is not observed in solutions. Therefore, if the mixture scatters light, it can be classified as a colloid or suspension, while if the mixture does not scatter light, it is a solution.
24: Making a solution is a physical change. This is because during the process of making a solution, the chemical composition of the solute and solvent remains the same. The solute is simply being dispersed in the solvent, and no chemical reaction is taking place. Therefore, there is no change in the chemical identity or composition of the solute or solvent.
Explanation:
hope it's help