Question :
21. Which of the following occurs when an ionic compound : 1335506
21. Which of the following occurs when an ionic compound dissolves in water to form a solution?
A)Ionic bonds break.D)Entropy increases.
B)Hydrogen bonds are disrupted.E)All of these
C)H2O – Ion attractive forces form.
22. Many cold packs contain ammonium nitrate and water. The dissolving of ammonium nitrate is endothermic. Which of the following best describes the energy and entropy changes that occur for the NH4NO3 system when ammonium nitrate and water are mixed to make a solution?
A)There is a net energy increase and an entropy increase.
B)There is a net energy increase and an entropy decrease.
C)There is a net energy decrease and an entropy decrease.
D)There is no a net change in energy or entropy.
23. Which of the following statements regarding the solution process is incorrect?
A)In a sodium chloride solution, the ions interact with the water molecules through ion-dipole forces.
B)Hydration is the process whereby water molecules surround solute particles.
C)A hydrated cation is surrounded by the partially positive end of the water molecules.
D)When an ionic compound dissolves, the ionic bonds break.
E)Some of the hydrogen bonds among the water molecules must break.
24. Which of the following statements regarding the solution process is incorrect?
A)When a solution is formed from an ionic compound, the anions and cations are evenly distributed throughout the solution.
B)When a polar covalent compound dissolves in water, dipole-dipole interactions take place between the water molecules and the solute molecules.
C)A nonpolar compound such as hexane, C6H14, forms London dispersion forces with a nonpolar solute, such as I2 during the solution process.
D)The solution process is always exothermic.
E)When an ionic solute dissolves, the entropy of the solution is greater than the original entropy of the crystalline form of the ionic substance.
25. When potassium nitrate is dissolved in water, the resulting solution feels cool to the touch. This means that:
A)the strength of attraction between the solute particles is greater than that of the attraction between the solute and solvent.
B)the strength of attraction between the solute and solvent particles is greater than that of the attraction between the solute particles.
C)the strength of attraction between the solute particles is equal to that of the attraction between the solute and solvent.
D)hydrogen bonds must be broken, which is an exothermic process.
E)there is a decrease in entropy for the solution.
26. Which of the following statements regarding solubility is incorrect?
A)A polar compound will dissolve an ionic compound due to ion-dipole interactions.
B)A nonpolar solvent will not interact strongly enough with ions to dissolve an ionic compound.
C)Nonpolar liquids will dissolve in one another because the intermolecular forces in the pure liquids are weak, and there is an increase in entropy.
D)Most solids are more soluble at higher temperature than at a lower temperature of the solvent.
E)Most gases are more soluble at a higher temperature than at a lower temperature of the solvent.
27. Which of the following statements regarding the solubility of oxygen in water is incorrect?
A)Water in contact with air contains a small amount of dissolved oxygen.
B)When water is heated, the first tiny bubbles that you see escaping from the warm water contain O2.
C)In warm weather, fish must come to the surface more often to get oxygen, since there is less dissolved oxygen in the water than in cooler weather.
D)If a sealed container has both oxygen and water, changing the pressure of the oxygen above the water will have no effect on the solubility of the oxygen in the water.
E)An increase in temperature causes an increase in the kinetic energy of the molecules in a solution, allowing oxygen molecules to escape more readily.
28. Which of the following increases the solubility of a gas in solution?
A)increasing gas pressure and increasing temperature
B)increasing gas pressure and decreasing temperature
C)decreasing gas pressure and increasing temperature
D)decreasing gas pressure and decreasing temperature
E)adding more water
29. If the solubility of a solid substance is 18.2 g/100 g water, which of the following best describes what eventually forms after 10.0 grams of the substance is mixed with 50.0 grams of water?
A)a saturated solution with some undissolved solid
B)an unsaturated solution with some undissolved solid
C)a saturated solution with no undissolved solid
D)an unsaturated solution with no undissolved solid
E)a supersaturated solution
30. If the solubility of sodium chloride at 25°C is 38.0 g/100 g water, which of the following best describes what eventually forms after 15.0 grams of sodium chloride is mixed with 50.0 grams of water at 25°C?
A)a saturated solution with some undissolved solid
B)an unsaturated solution with some undissolved solid
C)a saturated solution with no undissolved solid
D)an unsaturated solution with no undissolved solid
E)a supersaturated solution
