Cliffs AP Chemistry, 3rd Edition

Since, //

Ac

HAc

nV

nV

'

'

Ac sol n

= HAc sol n

• 
  
  
  
  • 7
  
  
  
  

6

A

@

Then, 7AHK+ ==a:#:#nnHAcAc- 18 10. --^55 0 05000 0488.. --x mol HAcx mol Ac-=184 10. M*

where x is negligible

*extra significant figure

pH = −log [H+] = −log (1.84 × 10 –5) = 4.73

6. Calculate the theoretical pH of the buffer solution with the added HCl (beaker 1).

0 0500. L#0 250. mol HAcL =0 0125. mol HAc

0 0500. L#0 0488. 0 200. mol AcL =0 0122. mol Ac

0 0250. L#0 250. Lmol H =0 00625. mol H

+ +

Ac-++H EHAc

Ac– H+ HAc

I 0.0122 0.00625 0.0125

C −0.00625 –0.00625 +0.00625

E 0.00595 ~0 0.01875

7AHK+-==a####nnHAcAc- 18 10.^55 0 018750 00595.. mol HAcmol Ac-=567 10. - M

pH = −log [H+] = −log (5.67 × 10 –5) = 4.25

7. Calculate the theoretical pH of the buffer solution with the added NaOH (beaker 2).

0 0500. L#0 250. mol HAcL =0 0122. mol HAc

0 0500. L#0 488. 0 200. mol AcL =0 0122. mol Ac

0 0250. L#0 250. mol OHL =0 00625. mol OH

HAc OH++--EAc H O 2

HAc OH– Ac–

I 0.0125 0.00625 0.0122

C −0.00625 −0.00625 +0.00625

E 0.00625 ~0 0.01845

.^6
.
HK..
n

n

mol Ac

18 10 mol HAc M

0 01845

a 0 00625 610 10

Ac

+-==####HAc (^5) - =-
7A -
pH = −log [H+] = −log (6.10 × 10 –6) = 5.21
Part III: AP Chemistry Laboratory Experiments