Back Titration
- Page ID
- 282813
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Preparation for Lab – A Guided Back Titration Calculation
Learning Objective:
Calculate analyte concentrations given experimental data from a back titration.
You are asked to determine the mass of calcium carbonate in a 0.125 g stick of chalk. You begin by dissolving the chalk in 50.00 mL of 0.200 M HCl. Then, you titrate any excess HCl with a standardized solution of KOH. You need 32.12 mL of 0.250 M KOH to reach the endpoint. What is the percent by mass of calcium carbonate in the chalk?
Let’s break it down!
- Draw a rough sketch of the steps in the experiment.
- Write chemical equations for…
- the complete reaction of calcium carbonate with HCl
- the reaction of HCl with KOH.
- the complete reaction of calcium carbonate with HCl
- How many moles of KOH did you use in the back titration?
- How many moles of HCl were present in solution after the chalk dissolved?
- How many moles of HCl did you add to the solution?
- How many moles of HCl reacted with the calcium carbonate?
- How many moles of calcium carbonate were present?
- What is the wt% of calcium carbonate in the 0.125 g stick of chalk?
Contributors and Attributions
- Jennifer Faust, Wooster College (jfaust@wooster.edu)
- Sourced from the Analytical Sciences Digital Library