Like all equilibrium constants, the value of K_w depends on temperature. At body temperature (37 °C), K_w = 2.4×10^–14. What are the [H₃O⁺] and pH of pure water at body temperature?

문제 54

The value of K_w increases with increasing temperature. Is the autoionization of water endothermic or exothermic?

문제 55

Calculate the pH of each acid solution. Explain how the resulting pH values demonstrate that the pH of an acid solution should carry as many digits to the right of the decimal place as the number of significant figures in the concentration of the solution. [H₃O⁺] = 0.044 M [H₃O⁺] = 0.045 M [H₃O⁺] = 0.046 M

문제 56

Determine the concentration of H₃O⁺ to the correct number of significant figures in a solution with each pH. Describe how these calculations show the relationship between the number of digits to the right of the decimal place in pH and the number of significant figures in concentration. pH = 2.50 pH = 2.51 pH = 2.52

문제 57a

For each strong acid solution, determine [H₃O⁺], [OH^–], and pH. a. 0.25 M HCl

문제 57b

For each strong acid solution, determine [H₃O⁺], [OH^–], and pH. b. 0.015 M HNO₃

문제 57c

For each strong acid solution, determine [H₃O⁺], [OH^–], and pH. c. a solution that is 0.052 M in HBr and 0.020 M in HNO₃

문제 57d

For each strong acid solution, determine [H₃O⁺], [OH^–], and pH. d. a solution that is 0.655% HNO₃ by mass (assume a density of 1.01 g/mL for the solution)

문제 58

Determine the pH of each solution. a. 0.048 M HI b. 0.0895 M HClO₄ c. a solution that is 0.045 M in HClO₄ and 0.048 M in HCl d. a solution that is 1.09% HCl by mass (assume a density of 1.01 g/mL for the solution)

문제 59

What mass of HI must be present in 0.250 L of solution to obtain a solution with each pH value?

a. pH = 1.25 b. pH = 1.75 c. pH = 2.85

문제 60

What mass of HClO₄ must be present in 0.500 L of solution to obtain a solution with each pH value? a. pH = 2.50 b. pH = 1.50 c. pH = 0.50

문제 61

What is the pH of a solution in which 224 mL of HCl(g), measured at 27.2 °C and 1.02 atm, is dissolved in 1.5 L of aqueous solution?

문제 62

What volume of a concentrated HCl solution, which is 36.0% HCl by mass and has a density of 1.179 g/mL, should be used to make 5.00 L of an HCl solution with a pH of 1.8?

문제 63

Determine the [H₃O⁺] and pH of a 0.100 M solution of benzoic acid.

문제 64

Determine the [H₃O⁺] and pH of a 0.200 M solution of formic acid.

문제 65

Determine the pH of an HNO₂ solution of each concentration. In which cases can you not make the simplifying assumption that x is small? a. 0.500 M b. 0.100 M c. 0.0100 M

문제 66

Determine the pH of an HF solution of each concentration. In which cases can you not make the simplifying assumption that x is small? (K_a for HF is 6.8×10^–4.) a. 0.250 M b. 0.0500 M c. 0.0250 M

문제 67

If 15.0 mL of glacial acetic acid (pure HC2H3O2) is diluted to 1.50 L with water, what is the pH of the resulting solution? The density of glacial acetic acid is 1.05 g/mL.

문제 68

Calculate the pH of a formic acid solution that contains 1.35% formic acid by mass. (Assume a density of 1.01 g/mL for the solution.)

문제 69

A 0.185 M solution of a weak acid (HA) has a pH of 2.95. Calculate the acid ionization constant (K_a) for the acid.

문제 71

Determine the percent ionization of a 0.125 M HCN solution.

문제 72

Determine the percent ionization of a 0.225 M solution of benzoic acid.

문제 73

What is the percent ionization of an acetic acid solution at the following concentrations? a. 1.00 M b. 0.500 M c. 0.100 M d. 0.0500 M

문제 74a

Calculate the percent ionization of a formic acid solution having the given concentration. a. 1.00 M