Question

Calculate the pH of each solution given the following - Express your answer using one decimal point:

Part A

[H3O+] = 7×10⁻⁴ M

Part B

[H3O+] = 7×10⁻⁹ M

Part C

[OH−] = 1×10⁻⁴ M

Part D

[OH−] = 5.0×10⁻¹¹ M

Part E

[H3O+] = 5.1×10⁻⁸ M

Part F

[OH−] = 8.3×10⁻⁴ M

Answer 1

A)

use:

pH = -log [H3O+]

= -log (7*10^-4)

= 3.1549

Answer: 3.2

B)

use:

pH = -log [H3O+]

= -log (7*10^-9)

= 8.1549

Answer: 8.2

C)

use:

pOH = -log [OH-]

= -log (1*10^-4)

= 4

use:

PH = 14 - pOH

= 14 - 4

= 10

Answer: 10.0

D)

use:

pOH = -log [OH-]

= -log (5*10^-11)

= 10.301

use:

PH = 14 - pOH

= 14 - 10.301

= 3.699

Answer: 3.7

E)

use:

pH = -log [H3O+]

= -log (5.1*10^-8)

= 7.2924

Answer: 7.3

F)

use:

pOH = -log [OH-]

= -log (8.3*10^-4)

= 3.0809

use:

PH = 14 - pOH

= 14 - 3.0809

= 10.9191

Answer: 10.9