Q: Which of the following best describes the percent ionization formula for a weak acid, as shown in the image?

$$\frac{[\mathrm{H^+}]_{eq}}{[\mathrm{HA}]_0} \times 100$$

Q: A solution at 50$$^\circC $$has $$[\mathrm{H_3O^+}] = 3.7 \times 10$$^{-4}$$ M. Using the K_w$ value from the table, what is $$[\mathrm{OH^-}]$$?

$$[\mathrm{OH^-}] = \frac{5.476 \times 10$$^{-14}$$}{3.7 \times 10$$^{-4}$$}$$

Question 1

Which of the following best explains why lemons and oranges taste sour, as shown in the first image?

Accepted Answer

They contain acids that release $$\mathrm{H^+}$$ ions in solution.

Question 2

A student dips blue and red litmus paper into a solution and observes that the blue paper turns red, but the red paper remains red (see image 2). What does this indicate about the solution?

Accepted Answer

The solution is acidic.

Question 3

Which of the following is a characteristic property of bases, as shown in the third image?

Accepted Answer

Bases taste bitter and turn red litmus paper blue.

Question 4

Based on the table of $$K_w$$ and temperature, what happens to the ionization constant of water as temperature increases?

Accepted Answer

$$K_w$$ increases with increasing temperature.

Question 5

Which formula is used to solve for the concentration of ions in a quadratic equilibrium problem, as shown in the images?

Accepted Answer

$$\frac{-b \pm \sqrt{b^2$ - 4ac}}{2a}$$

Question 6

Which of the following best describes the percent ionization formula for a weak acid, as shown in the image?

Accepted Answer

$$\frac{[\mathrm{H^+}]_{eq}}{[\mathrm{HA}]_0} 	imes 100$$

Question 7

A solution at 50$$^\circC $$has $$[\mathrm{H_3O^+}] = 3.7 	imes 10$$^{-4}$$ M. Using the K_w$ value from the table, what is $$[\mathrm{OH^-}]$$?

Accepted Answer

$$[\mathrm{OH^-}] = \frac{5.476 	imes 10$$^{-14}$$}{3.7 	imes 10$$^{-4}$$}$$

Question 8

Which of the following statements about the relationship between $$K_a$$ and $$K_b$$ for a conjugate acid-base pair is correct?

Accepted Answer

$$K_a 	imes K_b = K_w$$

Question 9

If a weak acid has an initial concentration $$[\mathrm{HA}]_0$$ and $$K_a$$, and $$\frac{[\mathrm{HA}]_0}{K_a} \u003e 500$$, what shortcut can be used to solve for equilibrium concentrations?

Accepted Answer

The $$-x in $$the denominator can be ignored (approximation method).

Question 10

Which of the following best describes the effect of adding a basic solution to an acidic salt, based on solubility principles?

Accepted Answer

The solubility of the acidic salt decreases.

Question 11

Which of the following is true about the taste and feel of bases, as shown in the third image?

Accepted Answer

Bases taste bitter and feel slippery.

Question 12

Given the formula for percent ionization of a weak base, which variable is in the numerator?

Accepted Answer

Equilibrium concentration of $$\mathrm{OH^-}$$

Question 13

Which of the following is the correct formula for calculating the pH of a solution?

Accepted Answer

$$\mathrm{pH} = -\log [\mathrm{H^+}]$$

Question 14

Which of the following best describes the relationship between acid strength and conjugate base strength?

Accepted Answer

A strong acid has a weak conjugate base.

Question 15

Which of the following is the correct equilibrium expression for the auto-ionization of water?

Accepted Answer

$$K_w = [\mathrm{H_3O^+}][\mathrm{OH^-}]$$

Acid-Base Equilibria: Concepts, Calculations, and Applications

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