Saturday, November 19, 2011

Chemistry: How to Solve Titration Questions

Strong Acid + Strong Base Titration
1. Convert concentrations to number of moles
2. Subtract the smaller n from the larger n
3. Calculate -log (difference÷total volume)
4. If the larger n is of the acid, the result is the pH. Otherwise, it's the pOH.

Weak Acid+ Strong Base Tritation

If there's more weak acid than strong base:
1. Subtract the two n's.
• conjugate base = n strong base ÷ total volume
• weak acid = difference ÷ total volume
2. Using the ICE table and the ka, calculate the new concentration of H+
3. pH=-log (H+)
If there's an equal amount of acid and base
1. conjugate base= n strong base ÷ total volume
2. kb = kw ÷ ka
3. [OH-] = square root of (kb* Cconjugate base)
4. pH = 14 + log [OH-]
If there's more strong base than weak acid
1. Find the difference between the two n's
2. Divide the difference by the total volume
3. pH = 14 + log [quotient]

Weak base+ Strong Acid Tritation
The steps are the same as those of Weak Acid+ Strong Base Tritation.