A two-step laboratory procedure is used to analyze a carbonate sample
CHEMISTRY · Multi-part · AP · Chemistry · Chemical Reactions · Chemical Reactions
Problem
A two-step laboratory procedure is used to analyze a carbonate sample.
Step 1: An aqueous solution of 0.100 M Na₂CO₃ is mixed with an equal volume of 0.100 M CaCl₂. The particulate diagram after mixing shows many compact aggregates made of alternating large black spheres (Ca²⁺) and pairs of smaller white spheres bonded together (CO₃²⁻) that settle out of solution. The remaining solution contains Na⁺ and Cl⁻ ions.
Step 2: After the solid from Step 1 is washed and transferred to a separate beaker, 0.500 M HCl(aq) is added slowly. A second particulate diagram shows the solid disappearing while numerous linear clusters of two red spheres (CO₂) rise through the liquid and escape. The solution now contains Ca²⁺ and Cl⁻ ions along with excess H₃O⁺.
Use this information to answer the questions below.
(a) Write the balanced net ionic equation for the reaction occurring in Step 1.
(b) Write the balanced net ionic equation for the reaction occurring in Step 2.
(c) Classify the reaction type for each step and explain how the particulate evidence supports your classifications.
(d) Calculate the minimum volume (in mL) of 0.500 M HCl required in Step 2 to completely react with 0.0500 mol of the precipitate formed in Step 1. Show all work.
(e) Discuss qualitatively how the electrical conductivity of the liquid phase changes from the start of Step 1 through the end of Step 2, relating your answer to the ionic species present at each stage.