Acid-Base Titration
A titration is a chemical analysis
involving the progressive addition of a solution of known solute concentration,
called the titrant, into a solution
of unknown concentration, called the sample.
The
purpose is to determine the quantity of a specified chemical in the sample,
from which the concentration and/or the molar mass of the chemical may be
determined. This is possible because the
titrant and the sample contain substances that react according to known
stoichiometry.
Generally,
the sample is placed in a flask and the titrant is placed in a burette.
In
an acid-base titration, we are interested in the point at which the number of
moles of acid is equal to the number of moles of base; this is referred to as
the equivalence point. An indicator is chosen so that the endpoint occurs precisely at the
equivalence point.
na = nb
caVa = cbVb
ca(25.0 mL) = (0.10
mol/L)(34.6 mL)
ca = 0.14 mol/L
Here is a video, showing how a titration is performed.
Homework:
Practice Problems p. 466 # 1-3 (hint: write out the balanced equation between the acid and the base first as stoichiometric ratios matter.)
Answers:
Success Criteria:
- know the Arrhenius and Bronsted-Lowry definitions of acid and base
- be able to define and explain the use of an indicator
- be familiar with the hydronium ion and what it represents
- know and apply the definition for ionization, dissociation, autoionization
- know the difference between a strong and weak electrolyte
- know the difference between a dilute and concentrated electrolyte solution
- be familiar with examples of strong, weak, mono-/di-/tri-/polyprotic acids
- be familiar with examples of strong, weak bases
- be able create an acid/base reaction and then label acid-conjugate base and base-conjugate acid pairs
- know the properties of acids and bases (taste, colour with litmus, etc)
- be able to draw the pH scale and label the regions
- be able to do acid-base calculations: pH, [H+], [OH-], titration (caVa = cbVb)
- know the info in the Acid Rain reading
- be able to create a balanced equation for an acid-base neutralization reaction
- know the definitions and theory associated with titration
Acid-Base Review - do not do #6, 9, 13, 17
Answers:
