Introduction to Acids and Bases - AP Chemistry

1. Identify the conjugate base of $H_2O$.

   The conjugate base of $H_2O$ is $OH^-$.. Loses a proton to form the conjugate base.

2. What is a Lewis acid?

   A Lewis acid is an electron pair acceptor. Receives an electron pair from a donor.

3. State the formula for calculating pH.

   $pH = -\text{log}_{10} [H^+]$. Negative logarithm of hydrogen ion concentration.

4. Identify the pH range for acidic solutions.

   Acidic solutions have a pH less than 7. Higher $[H^+]$ than $[OH^-]$.

5. Identify the conjugate acid of $OH^-$.

   The conjugate acid of $OH^-$ is $H_2O$. Gains a proton to form the conjugate acid.

6. What is the $pH$ of a $0.001$ M $NaOH$ solution?

   $pH = 11$. Strong base: $pOH = 3$, so $pH = 14 - 3$.

7. What is the definition of a strong acid?

   A strong acid completely ionizes in solution. 100% dissociation in aqueous solution.

8. Identify the conjugate acid of $NH_3$.

   The conjugate acid of $NH_3$ is $NH_4^+$.. Gains a proton to form the conjugate acid.

9. Which base is stronger: $NaOH$ or $NH_3$?

   $NaOH$ is stronger than $NH_3$. $NaOH$ is strong, $NH_3$ is weak.

10. What is the pH of a neutral solution at 25°C?

    The pH of a neutral solution is 7. Equal concentrations of $H^+$ and $OH^-$.

11. Identify the conjugate base of $H_2SO_4$.

    The conjugate base of $H_2SO_4$ is $HSO_4^-$. Loses one proton from diprotic acid.

12. What is the definition of a base according to Arrhenius?

    A base increases $[OH^-]$ in aqueous solution. Releases hydroxide ions when dissolved.

13. What is the pH of pure water at 25°C?

    The pH of pure water is 7. Neutral because $[H^+] = [OH^-]$.

14. What is the ion product constant for water ($K_w$) at 25°C?

    $K_w = 1.0 \times 10^{-14}$ at 25°C. Product of $[H^+]$ and $[OH^-]$ concentrations.

15. What is a Lewis base?

    A Lewis base is an electron pair donor. Provides an electron pair to an acceptor.

16. Define a Brønsted-Lowry base.

    A Brønsted-Lowry base is a proton acceptor. Receives $H^+$ from another species.

17. What is the definition of a weak base?

    A weak base partially dissociates in solution. Incomplete dissociation in aqueous solution.

18. What is the definition of a strong base?

    A strong base completely dissociates in solution. 100% dissociation in aqueous solution.

19. What is the pOH of a solution with $[OH^-] = 1.0 \times 10^{-4}$ M?

    $pOH = 4$. Calculated using $pOH = -\log[OH^-]$.

20. Which acid is stronger: $HCl$ or $HF$?

    $HCl$ is stronger than $HF$. $HCl$ is a strong acid, $HF$ is weak.

21. How does increasing $[OH^-]$ affect pOH?

    Increasing $[OH^-]$ decreases pOH. pOH decreases as basicity increases.

22. What is the $K_w$ expression for water?

    $K_w = [H^+][OH^-]$. Autoionization equilibrium expression for water.

23. Which ion is common in all acidic solutions?

    The common ion is $H^+$. Present in all aqueous acid solutions.

24. Identify the pH range for basic solutions.

    Basic solutions have a pH greater than 7. Higher $[OH^-]$ than $[H^+]$.

25. Define a Brønsted-Lowry acid.

    A Brønsted-Lowry acid is a proton donor. Gives up $H^+$ to another species.

26. What is the $pH$ of a $0.01$ M $HCl$ solution?

    $pH = 2$. Strong acid completely ionizes: $pH = -\log(0.01)$.

27. What is the $pK_a$ expression for an acid?

    $pK_a = -\text{log}_{10} K_a$. Negative logarithm of acid dissociation constant.

28. What is the definition of an acid according to Arrhenius?

    An acid increases $[H^+]$ in aqueous solution. Releases hydrogen ions when dissolved.

29. What is the $K_a$ expression for $HA \rightleftharpoons H^+ + A^-$?

    $K_a = \frac{[H^+][A^-]}{[HA]}$. Equilibrium expression for acid dissociation.

30. What is the $pK_b$ expression for a base?

    $pK_b = -\text{log}_{10} K_b$. Negative logarithm of base dissociation constant.

31. How does increasing $[H^+]$ affect pH?

    Increasing $[H^+]$ decreases pH. pH decreases as acidity increases.

32. Identify the conjugate base of $HCl$.

    The conjugate base of $HCl$ is $Cl^-$. Loses a proton to form the conjugate base.

33. Which ion is common in all basic solutions?

    The common ion is $OH^-$. Present in all aqueous base solutions.

34. What is the definition of a weak acid?

    A weak acid partially ionizes in solution. Incomplete dissociation in aqueous solution.

35. What is the relationship between pH and pOH?

    $pH + pOH = 14$ at 25°C. Based on the ion product of water.

36. What is the pH of a solution with $[H^+] = 1.0 \times 10^{-3}$ M?

    $pH = 3$. Calculated using $pH = -\log[H^+]$.

37. What is the effect of temperature on $K_w$ of water?

    $K_w$ increases with temperature. Higher temperature increases ion product.

38. State the formula for calculating pOH.

    $pOH = -\text{log}_{10} [OH^-]$. Negative logarithm of hydroxide ion concentration.

39. What is the $K_b$ expression for $BOH \rightleftharpoons B^+ + OH^-$?

    $K_b = \frac{[B^+][OH^-]}{[BOH]}$. Equilibrium expression for base dissociation.

Study these flashcards