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1. Using your measured pH values, calculate the concentration of H (M) in beaker

ID: 551564 • Letter: 1

Question

1. Using your measured pH values, calculate the concentration of H (M) in beakers 1 and 3, before and after the addition of HCI. Organize your answers in a table as shown below. Initial Initial [H] measured Final H ] (M) after By what factor measured pH addition of did the [H"] HCI pH (M) increase? Beaker 1 (0.1M NaCI) .08 Beaker 3 Buffer) 6,93 6.5 6 2. Using your measured pH values, calculate the concentration of H (M) in beakers 2 and 4, before and after the addition of NaOH. Organize your answers in a table as shown below Initial [H] Final H ] (M) after By what factor measured pH addition of did the [H ] (M) decrease? Initial Initial [H'] measured(M) pH NaOH Beaker 2 (0. 1 M NaCl) Beaker 4 (Buffer) .04 6.93 | 4.0 3

Explanation / Answer

1.

Beaker 1:

Initial pH = 8.08

Initial [H+] = 10-8.08 = 8.32 x 10-9 M

Final pH = 1.74

Final [H+] = 10-1.74 = 1.82 x 10-2 M

Increment in  [H+] = ( 1.82 x 10-2 ) / ( 8.32 x 10-9 ) = 2.18 x 106

Beaker 3:

Initial pH = 6.92

Initial [H+] = 10-6.92 = 1.2 x 10-7 M

Final pH = 6.56

Final [H+] = 10-6.56 = 2.75 x 10-7 M

Increment in  [H+] = ( 2.75 x 10-7 ) / ( 1.2 x 10-7 ) = 2.3

2.

Beaker 1:

Initial pH = 8.04

Initial [H+] = 10-8.04 = 9.12 x 10-9 M

Final pH = 11.52

Final [H+] = 10-11.52 = 3.02 x 10-12 M

Increment in  [H+] = ( 3.02 x 10-12 ) / ( 9.12 x 10-9 ) = 3.31 x 10-4

Beaker 3:

Initial pH = 6.93

Initial [H+] = 10-6.93 = 1.17 x 10-7 M

Final pH = 7.02

Final [H+] = 10-7.02 = 9.55 x 10-8 M

Increment in  [H+] = ( 9.55 x 10-8 ) / ( 1.17 x 10-7 ) = 0.816