Measurement of Egg Quality
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Titration of Egg White

Introduction

This experiment is intended to illustrate the part played by C02 and the bicarbonate ion in the pH change of egg white during storage of shell eggs.


Questions to Consider

  1. How is the buffering effect going to be demonstrated?
  2. How many eggs are required by each group for this part of the experiment? Which part of the egg is required?
  3. How many titrations will you need to carry out?
  4. What is a buffer?
  5. Give a definition of buffering systems?
  6. What component of egg white gives it its buffering ability? 
  7. Would you expect the concentration of this component to increase or decrease during storage?
  8. How would you anticipate the influence of storage on buffering capacity of egg white?
  9. How might this be reflected in your titration curves? Would more or less acid be required to reach a specified pH when buffering effect is efficient?
  10. How does carbonic acid act as a buffer?
  11. What are the two steps in the dissociation of carbonic acid?
  12. Each dissociation step has buffering potential. At what stage of each dissociation step is buffering capacity at its maximum?  
  13. What is the corresponding pH of maximum buffering for each dissociation step?
  14. What are these pH values known as?
  15. How is this maximum buffering reflected in the titration curves?
  16. For any given pH on the titration curve the extent of dissociation can be calculated. How is this calculation carried out?
  17. What will determine which pka you use in your calculation?
  18. Every buffering system has a conjugate base and acid. When using the Henderson-Hasslebach equation what is a equivalent to, the base or acid?
  19. For the first step (pka = 6.4) in the dissociation of carbonic acid, define the base and acid.  
  20. For the second step (pka = 10.3) in the dissociation of carbonic acid, define the base and acid.
  21. What is the value of the buffering effect of egg white?

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