AP Chem Unit 8.1-8.2

Which of the following accounts for the observation that the pH of pure water at 37°C is 6.8?

• At 37C water is acidic

• At 37C water has a lower density than it does at 25C

• At 37C the Kw of water is greater than at 25C

• At 37C water ionizes less than at 25C.

At 25C, aqueous solutions with a pH of 6 have a hydroxide ion concentration, [OH-], of

• 1 x 10^-14M

• 1 x 10^-8 M

• 1 x 10^-6

• 8 M

The value of Kw at 10C is 2.93 x 10^-15. What is the pH of pure water at 10C?

• 3.0

• 6.8

• 7.0

• 7.3

In pure water, some of the molecules ionize according to the equation H2O → H+ + OH− . The extent of the ionization increases with temperature. A student heats pure water and records the measured pH at 50°C as 6.6. Based on this information, which of the following mathematical relationships gives the pOH of pure water at 50°C?

• pOH = pH

• pOH = 1/pH

• pOH = 14 - pH

• pOH = (1x10^14)/pH

How can 50. mL of sodium hydroxide solution with a pH of 12.00 be converted to a sodium hydroxide solution with a pH of 11.00 ?

• By diluting the solution with distilled water to a total volume of 100 mL

• By diluting the solution with distilled water to a total volume of 500mL

• By adding 50 mL of 0.10 M HCl

• By adding 50 mL of 0.10 M NaOH

Which one of the following is a strong electrolyte in aqueous solution?

• NH3

• BH3

• H2

• H2S

• HBr

Which one is a weak acid?

• H2SO4

• HNO3

• H2SO3

• HCl

• HI

Which one is a strong base?

• Mg(OH)2

• Ca(OH)2

• ZnOH

• NH3

• AgOH

Which one of the following is the correct mathematical expression to use to calculate the pH of a 0.10 M Ba(OH)2(aq) at 25C?

• pH = -log(0.10)

• pH = -log(0.20)

• pH = 14.00 - log(0.10)

• pH = 14.00 + log(0.20)

The pH of a solution prepared by the addition of 10. mL of 0.002 M KOH(aq) to 10. mL of distilled water is closest to

• 12

• 11

• 10

• 4

• 3

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NGSS.HS-PS1-7