Summary: Ionization Constant Of A Weak Acid

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The name of the lab that was performed within Chemistry II 153L is titled “Ionization Constant of a Weak Acid, Ka” This lab is very important because it incorporates a great amount of theories that we have learned throughout our Chemistry course. By the word ‘theory’ this can be defined as a well-established explanation for scientific data. Theories typically cannot be proven, but they can be established if several different scientific investigators test them. These theories are named, Arrhenius acids and bases, Bronsted – Lowry acids and bases, Strong versus weak acids and bases, Chemical equilibria, Ka, pH, Equivalence and half equivalence points, and lastly Le Chatelier’s principle. All these theories tie this particular lab together and …show more content…
An equivalence point can be defined as the point at which chemically equivalent quantities of acid and base have been mixed. Whereas a half equivalence point can be defined as the mill moles of base added are only half the mill moles of acid originally present, leaving the concentrations of the conjugate base and the remaining weak acid to the be same. Another way of saying this is that at half-equivalence, pH is equal to the pKa, which is what we learned throughout the previous theory. This theory is mainly seen on a titration curve, but is known as the neutralization/half neutralization point within our lab. On a titration curve the equivalence point is also known to be the point where the volume of base is split in half, allowing you to determine the dependent, pH variable. The equivalence can also have different pH’s, a neutral salt can be 7, an acidic salt can be less than 7, and an basic salt can have a pH of greater than 7. With regards to our lab experiment, since the weak acid was fully converted to NaOH, this allowed us to have a greater pH, which is exactly what should have happened. The equivalence point and half equivalent point are both very unique in their own way and this is how we used it when putting our whole titration curve