Please answer all of the following: 1.) An acid with a pKa of 8.0 is present in

Question

Please answer all of the following:
1.) An acid with a pKa of 8.0 is present in a solution with a pH of 6.0. What is the ratio of the protonated to the deprotonated form of the acid?
2.) Calculate the concentration of acetic acid and acetate ion in 0.2M acetate buffer at pH 5. The pKa of acetic acid is 4.76.
3.) You are working in a high powered clinical biochemistry lab. The chief scientist rushes in and announces, "I need 500ml of 0.2M acetate, pH 5.0 STAT!" You have solid anhydrous sodium acetate (MW = 82g mol-1) and a solution of 1M acetic acid. Describe how you would make the buffer.
4.) Following a bout of intense exercise, the pH of the exerciser's blood was found to be 7.1. If the HCO3 concentration is 8mM, and the pKa for HCO3 is 6.1, what is the concentration of CO2 in the blood?
5.) If a patient has a blood pH of 7.03 and CO2 of 1.2mM, what is the HCO3 in the patients blood? The pKa of HCO3 is 6.1. Please answer all of the following:
1.) An acid with a pKa of 8.0 is present in a solution with a pH of 6.0. What is the ratio of the protonated to the deprotonated form of the acid?
2.) Calculate the concentration of acetic acid and acetate ion in 0.2M acetate buffer at pH 5. The pKa of acetic acid is 4.76.
3.) You are working in a high powered clinical biochemistry lab. The chief scientist rushes in and announces, "I need 500ml of 0.2M acetate, pH 5.0 STAT!" You have solid anhydrous sodium acetate (MW = 82g mol-1) and a solution of 1M acetic acid. Describe how you would make the buffer.
4.) Following a bout of intense exercise, the pH of the exerciser's blood was found to be 7.1. If the HCO3 concentration is 8mM, and the pKa for HCO3 is 6.1, what is the concentration of CO2 in the blood?
5.) If a patient has a blood pH of 7.03 and CO2 of 1.2mM, what is the HCO3 in the patients blood? The pKa of HCO3 is 6.1. Please answer all of the following:

2.) Calculate the concentration of acetic acid and acetate ion in 0.2M acetate buffer at pH 5. The pKa of acetic acid is 4.76.
3.) You are working in a high powered clinical biochemistry lab. The chief scientist rushes in and announces, "I need 500ml of 0.2M acetate, pH 5.0 STAT!" You have solid anhydrous sodium acetate (MW = 82g mol-1) and a solution of 1M acetic acid. Describe how you would make the buffer.
4.) Following a bout of intense exercise, the pH of the exerciser's blood was found to be 7.1. If the HCO3 concentration is 8mM, and the pKa for HCO3 is 6.1, what is the concentration of CO2 in the blood?
5.) If a patient has a blood pH of 7.03 and CO2 of 1.2mM, what is the HCO3 in the patients blood? The pKa of HCO3 is 6.1.

Explanation / Answer

1. Since pH= pKa+log {[Protonated]/ [Unprotonated]}

6= 8 + log {[Protonated]/ [Unprotonated]}

[Protonated]/ [Unprotonated] = 10(-2)= 0.01

2. pH= pKa + log { [Acetate]/ [Acetic acid]}

5= 4.76 + log {[0.2]/[Acetic acid] ( since aceitc acid is weak acid its extent of ionization is considered negligible)

log (0.2/[acetic acid] = 0.24

0.2/ [Acetic acid] = 10(0.24) =1.74

[Acetic acid ] =0.2/1.74 =0.1149

3. Pka of acetic acid =4.76

pH= Pka + log [ acetate ion/ acetic/acid]

5= 4.76 + log {[acetate]/ [1]}

0.24= log [acetate]

concentration of acetate = 10(0.24)= 1.74 moles/L

but required concentration is 500ml of 0.2

from M1V1= M2V2

1.74*V1= 500*0.2

V1= 500*0.2/1.74=57.47 ml

take 57.47 ml of 1.74 mol/L of sodium acetate and dilute to 500ml

4. H2CO3<---> HCO3- +H+

pH= Pka + log [HCO3-]/[H2CO3]

7.1= 6.1 + log [HCO3-]/[H2CO3]

[HCO3-]/[H2CO3] =10

[H2CO3] =8/10 =0.8 mM

H2CO3----> H2O+CO2

Concentration of H2CO3 is same as that of H2CO3= 0.8mM

5. 7.03= 6.1 +log{[HCO3-]/[1.2]}

[HCO3-]/1.2 = 10(0.93)= 8.51

[HCO3-] =8.51*1.2 =10.212 mM

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