Review Question For Acid Base And Titration Labs And Calculation Review

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Questions already from Labs

Questions from Titration Labs

1. For the weak acid and weak base titration, please explain (step by step) how you would determine the pH at equilavence point and the pH at the half-way point. Then actually determine these two pH for the weak acid and weak base.

2. For each pH indicator, calculate the pH range of the endpoint. Explain (including the indicator colors) if the pH indicator worked appropriately.

3. Explain how determining the approrpriate pH indicator for a weak acid and strong acid are different. If you had to be correct in the choice of pH indicator, which would you want to use, the weak or strong acid and why?

Questions for Standardizing an Acid, Titrating base by Acid, and pH Indicator

Part I: Standardize Strong Acid
1. Write up step to perform this task under Procedure section
2. Calculate Molarity of unknown Strong acid.
3. Put all graphs in lab notebook and include a title & chemicals

Questions:
a. On the graph, draw dotted lines to show what the pH is at the equilivance point (all trials) and the half-way point (only for weak acid).
b. Using your graph information, determine the Ka of the weak acid.
c. Using your lab information, calculate the theoretical pH at the equilivance point.
d. For Trial 1 & 2, at what pH did the pH indicator change color (called endpoint of indicator) for each trial? Was this during the pH peak? Which pH indicator would you use for this titration, explain?
e. For Trial 3, what was the endpoint of the pH indicator? Was this during the pH peak? For this trial, could you switch the pH indicator and not affect the experiment, explain? From your knowledge of pH indicators and the chemicals in this trial, would you have expected this,explain?

Part II: Titrating Weak Base with Strong Acid
1. Write up steps to perform this task under Procedure section
2. Calculate Molarity of Weak Base
3. Put the graph in the lab notebook and include a title & chemcials

Questions:
a. On the graph, draw dotted lines to show what the pH is at the equilivance point and the half-way point.
b. Using your graph information, determine the Ka of the weak acid.
c. Using your lab information, calculate the theoretical pH at the equilivance point.
d. Could you use either pH indicator from Part I for this titration.
e. In pencil (so if you make a mistake, you can fix it), draw the titration curve if the base was a strong base not weak base (all other parameters in lab are the same).

Making a Buffer Solution

1. If some of the solid salt (w/conjugate base of weak acid) you add did not make it in the solution, how would change the pH of the resulting buffer solution.
2. If the molarity of the weak base was greater than you thought, how would that change the pH of the resulting buffer solution.

Review Problems for Acid, Base, Salts, Buffers, and Titration

1. Calculate the pH of a solution prepared by adding 35.0g of benzoic acid, HC₇H₅O₂, and 25.0g of sodium benzoate, NaC₇H₅O₂, to enough water to form a 250.ml of solution.(17.6a)

2. a)What is the ratio of HCO₃^1- to H₂CO₃ in blood of pH of 7.4? b) What is the ratio of HCO₃^1- to H₂CO₃ in an exhausted marathon runner whose blood pH of 7.1? (17.7)

3. Consider the titration of 30.0ml of 0.100M propionic acid, HC₃H₅O₂. Calculate the pH of the solution upon addition of the following volume of 0.100M NaOH: a)30.0ml and b)45.0ml.(17.25df)

4.Consider the titration of 40.0ml of 0.100M NH₃. Calculate the pH of the solution upon addition of the following volume of 0.100M HCl: a)20.0ml and b)40.0ml. (17.26bd)