The percentages of neutral and protonated forms present in a solution of 0.0010M pyrimidine at pH = 7.3 are to be calculated if the pKa of pyrimidinium ion is 1.3. Concept introduction: pH And pKa are related by Henderson-Hasselbalch equation as Knowing pH and pKa values, the ratio between the two forms and from which their percentages can be determined. To calculate: The percentages of neutral and protonated forms present in a solution of 0.0010M pyrimidine at pH = 7.3, if the pKa of pyrimidinium ion is 1.3. Answer: At pH = 7.3, almost 100% pyrimidine molecules exist in the neutral form. Explanation: Deprotonation of the ammonium ion of a base can be represented as, The Henderson-Hasselbalch can be written as Substituting the values of pH and pKa, we get Thus the concentration of neutral form is 10 6 times more than the protonated form. Hence almost 100% pyrimidine molecules exist in the neutral form. Conclusion: At pH = 7.3, almost 100% pyrimidine molecules exist in the neutral form.

Question

5. Calculate the total amount of heat transferred as 50 g of wat Specific heat H₂O (g) 2.00 J/g°C -10 °C. Specific heat H₂O (1) Specific heat H₂O (s) 4.18 J/g°C 2.11 J/g°C Heat of vaporization 2260 J/g Heat of fusion 334 J/g Melting point 0°C 6. Calculate the total amount of heat transferred as 25 g of water is heated from 50 °C to 100 °C as a gas. Boiling point 100 °C

Answer 1

Question

Chapter 24.5, Problem 7P

Interpretation Introduction

Interpretation:

The percentages of neutral and protonated forms present in a solution of 0.0010M pyrimidine at pH = 7.3 are to be calculated if the pKa of pyrimidinium ion is 1.3.

Concept introduction:

pH And pKa are related by Henderson-Hasselbalch equation as

Knowing pH and pKa values, the ratio between the two forms and from which their percentages can be determined.

To calculate:

The percentages of neutral and protonated forms present in a solution of 0.0010M pyrimidine at pH = 7.3, if the pKa of pyrimidinium ion is 1.3.

Answer:

At pH = 7.3, almost 100% pyrimidine molecules exist in the neutral form.

Explanation:

Deprotonation of the ammonium ion of a base can be represented as,

The Henderson-Hasselbalch can be written as

Substituting the values of pH and pKa, we get

Thus the concentration of neutral form is 10⁶ times more than the protonated form. Hence almost 100% pyrimidine molecules exist in the neutral form.

Conclusion:

At pH = 7.3, almost 100% pyrimidine molecules exist in the neutral form.

Expert Solution & Answer

Trending nowThis is a popular solution!

See solution

Check out sample textbook solution

Students have asked these similar questions

5. Calculate the total amount of heat transferred as 50 g of wat Specific heat H₂O (g) 2.00 J/g°C -10 °C. Specific heat H₂O (1) Specific heat H₂O (s) 4.18 J/g°C 2.11 J/g°C Heat of vaporization 2260 J/g Heat of fusion 334 J/g Melting point 0°C 6. Calculate the total amount of heat transferred as 25 g of water is heated from 50 °C to 100 °C as a gas. Boiling point 100 °C

Calculate the total amount of heat transferred as 50 g of Water -10°C. Calculate the total amount of heat transferred as 25 g of water is heated from 50°C to 100°C as a gas. \table[[Specific heat H₂O(g), 2.00°C Η 2 g 5. Calculate the total amount of heat transferred as 50 g of wat Specific heat H₂O (g) 2.00 J/g°C -10 °C. 4.18 J/g°C 2.11 J/g°C 2260 J/g 334 J/g Specific heat H₂O (1) Specific heat H₂O (s) Heat of vaporization Heat of fusion Melting point 6. Calculate the total amount of heat transferred as 25 g of water is heated from 50 °C to 100 °C as a gas. Boiling point 100 °C 0°C

Write formulas for ionic compounds composed of the following ions. Use units as a guide to your solutions. 24. sodium and nitrate 25. calcium and chlorate 26. aluminum and carbonate 27. CHALLENGE Write the formula for an ionic compound formed by ions from a group 2 element and polyatomic ions composed of only carbon and oxygen.show work step by step