Representations of Solutions - AP Chemistry

1. What is Raoult's Law formula?

   $P_A = X_A P^0_A$, where $P_A$ is vapor pressure of component $A$. Law relates vapor pressure to mole fraction in ideal solutions.

2. What is the effect of a solute on freezing point of a solution?

   Lowers the freezing point. Solute particles interfere with crystal formation at normal freezing point.

3. What is an unsaturated solution?

   A solution that can dissolve more solute at a given temperature. Solution can still accept additional solute below saturation point.

4. What is a supersaturated solution?

   A solution that contains more solute than can dissolve at the current temperature. Metastable state containing excess solute that can crystallize out.

5. What is the principle of Le Chatelier's?

   System at equilibrium will adjust to counteract disturbances. Fundamental principle describing system response to external changes.

6. Find the new concentration after dilution: $M_1 = 6$, $V_1 = 1$, $V_2 = 3$.

   New concentration is 2 M. Apply dilution equation: $6 \times 1 = M_2 \times 3$, so $M_2 = 2$.

7. Which equation represents the dilution of solutions?

   $M_1V_1 = M_2V_2$, where $M$ is molarity and $V$ is volume. Conservation equation for dilutions where moles remain constant.

8. Which formula represents freezing point depression?

   $\Delta T_f = iK_f m$, where $i$ is van't Hoff factor. Formula accounts for number of particles formed when solute dissolves.

9. What is osmotic pressure?

   Pressure required to stop osmosis. External pressure needed to prevent solvent flow across membrane.

10. How is molality defined in a solution?

    Molality is the number of moles of solute per kilogram of solvent. Uses solvent mass instead of solution volume, making it temperature-independent.

11. Find the new concentration after dilution: $M_1 = 6$, $V_1 = 1$, $V_2 = 3$.

    New concentration is 2 M. Apply dilution equation: $6 \times 1 = M_2 \times 3$, so $M_2 = 2$.

12. Identify the property of a colligative property.

    Depends on the number of solute particles, not their identity. Properties determined by particle count, not chemical identity.

13. Determine the freezing point depression: $i = 3$, $K_f = 1$, $m = 0.2$.

    Freezing point depression is 0.6°C. Apply formula: $\Delta T_f = 3 \times 1 \times 0.2 = 0.6$.

14. What is the effect of a solute on boiling point of a solution?

    Raises the boiling point. Solute particles disrupt solvent vaporization, requiring higher temperature.

15. What describes a hypotonic solution?

    Solution with lower solute concentration than another. Comparative term indicating lesser solute concentration relative to reference.

16. What is the formula for calculating molality?

    $m = \frac{n}{m_{\text{solvent}}}$, where $n$ is moles of solute and $m_{\text{solvent}}$ is kg of solvent. Formula uses kilograms of solvent in the denominator.

17. How is molality defined in a solution?

    Molality is the number of moles of solute per kilogram of solvent. Uses solvent mass instead of solution volume, making it temperature-independent.

18. What is the effect of pressure on gas solubility in liquids?

    Increased pressure increases gas solubility. Henry's Law: higher pressure forces more gas molecules into solution.

19. State Henry's Law formula.

    $C = kP$, where $C$ is solubility and $P$ is pressure. Linear relationship where $k$ is Henry's law constant.

20. What is the formula for mole fraction?

    $X_A = \frac{n_A}{n_{\text{total}}}$, where $n_A$ is moles of component $A$. Ratio formula where all mole fractions sum to 1.

21. Calculate osmotic pressure: $i = 1$, $M = 0.5$, $R = 0.0821$, $T = 300$.

    Osmotic pressure is 12.315 atm. Apply formula: $\pi = 1 \times 0.5 \times 0.0821 \times 300$.

22. Which formula represents boiling point elevation?

    $\Delta T_b = iK_b m$, where $i$ is van't Hoff factor. Formula includes van't Hoff factor for ionic dissociation effects.

23. What is Henry's Law?

    Solubility of gas in liquid is proportional to the pressure of gas above the liquid. Direct proportionality between gas pressure and dissolution concentration.

24. Identify the property of a colligative property.

    Depends on the number of solute particles, not their identity. Properties determined by particle count, not chemical identity.

25. What is the principle of Le Chatelier's?

    System at equilibrium will adjust to counteract disturbances. Fundamental principle describing system response to external changes.

26. What is a saturated solution?

    A solution in which no more solute can dissolve at a given temperature. Maximum solubility reached at equilibrium for given conditions.

27. Identify the property of a colligative property.

    Depends on the number of solute particles, not their identity. Properties determined by particle count, not chemical identity.

28. Find the new concentration after dilution: $M_1 = 6$, $V_1 = 1$, $V_2 = 3$.

    New concentration is 2 M. Apply dilution equation: $6 \times 1 = M_2 \times 3$, so $M_2 = 2$.

29. Determine the boiling point elevation: $i = 2$, $K_b = 0.5$, $m = 1$.

    Boiling point elevation is 1°C. Apply formula: $\Delta T_b = 2 \times 0.5 \times 1 = 1$.

30. What describes an isotonic solution?

    Solutions with equal solute concentrations. No net osmotic pressure difference exists between the solutions.

31. State the formula for calculating molarity.

    $M = \frac{n}{V}$, where $n$ is moles of solute and $V$ is volume in liters. Standard formula relating moles of solute to liters of solution.

32. Define mole fraction.

    Mole fraction is the ratio of moles of one component to the total moles in the mixture. Represents the fraction of total moles contributed by one component.

33. Determine the boiling point elevation: $i = 2$, $K_b = 0.5$, $m = 1$.

    Boiling point elevation is 1°C. Apply formula: $\Delta T_b = 2 \times 0.5 \times 1 = 1$.

34. What is a saturated solution?

    A solution in which no more solute can dissolve at a given temperature. Maximum solubility reached at equilibrium for given conditions.

35. What is the principle of Le Chatelier's?

    System at equilibrium will adjust to counteract disturbances. Fundamental principle describing system response to external changes.

36. What happens to vapor pressure when a non-volatile solute is added?

    Vapor pressure decreases. Raoult's Law: solute particles reduce solvent's tendency to vaporize.

37. What is the unit of molality?

    Moles per kilogram (mol/kg). Units reflect moles of solute per mass of solvent.

38. What is a saturated solution?

    A solution in which no more solute can dissolve at a given temperature. Maximum solubility reached at equilibrium for given conditions.

39. How is molality defined in a solution?

    Molality is the number of moles of solute per kilogram of solvent. Uses solvent mass instead of solution volume, making it temperature-independent.

40. Determine the boiling point elevation: $i = 2$, $K_b = 0.5$, $m = 1$.

    Boiling point elevation is 1°C. Apply formula: $\Delta T_b = 2 \times 0.5 \times 1 = 1$.

41. Which formula represents freezing point depression?

    $\Delta T_f = iK_f m$, where $i$ is van't Hoff factor. Formula accounts for number of particles formed when solute dissolves.

42. Identify the formula for percent mass.

    Percent mass = $\frac{\text{mass of solute}}{\text{mass of solution}} \times 100\%$. Mass percentage formula multiplied by 100 for percentage.

43. Describe the common ion effect.

    Decrease in solubility of an ionic compound by adding a common ion. Added common ions shift equilibrium, reducing compound solubility.

44. Which formula represents freezing point depression?

    $\Delta T_f = iK_f m$, where $i$ is van't Hoff factor. Formula accounts for number of particles formed when solute dissolves.

45. What is the definition of molarity?

    Molarity is the number of moles of solute per liter of solution. This is the fundamental concentration unit relating solute amount to solution volume.

46. Calculate molality: 3 moles solute in 2 kg solvent.

    1.5 mol/kg. Divide moles by solvent mass: $3 \div 2 = 1.5$.

47. How do you calculate the van't Hoff factor, $i$?

    $i$ is the number of particles the solute dissociates into. Represents degree of dissociation for ionic compounds in solution.

48. What describes a hypertonic solution?

    Solution with higher solute concentration than another. Comparative term indicating greater solute concentration relative to reference.

49. Find the molarity: 2 moles solute in 4 L solution.

    0.5 mol/L. Divide moles by volume: $2 \div 4 = 0.5$.

50. What is the unit of molarity?

    Moles per liter (mol/L). Standard SI unit for concentration in chemistry.

51. Identify the solution type: 1 M NaCl inside, 0.5 M NaCl outside.

    Hypertonic inside, hypotonic outside. Higher concentration inside makes it hypertonic relative to outside.

52. What is the formula for osmotic pressure?

    $\pi = iMRT$, where $\pi$ is osmotic pressure. Van't Hoff equation incorporating gas law principles for osmosis.

53. Compute the mole fraction: 2 moles $A$, 3 moles $B$.

    Mole fraction of $A$ is 0.4. Divide component moles by total: $2 \div (2+3) = 0.4$.

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