Objectives
- to observe the reaction between solutions of NaCO₃and CaCl₂
- to determine which of the reactants is the limiting reactant and which is the excess reactant
- to determine the theoretical mass of precipitate that should form
- to compare the actual mass with the theoretical mass of precipitate and calculate the percent yield
Supplies
- Equipment: centigram balance, 2 graduated cylinders(25ml), beaker(250ml), wash bottle, filtering apparatus(ring with stand, Erlinmeyer flask(250ml)+funnel), filter paper, lab apron, safety goggles
- Chemical Reagents: 0.70M NaCO₃solution, 0.50 CaCl₂solution
Procedure
Part Ⅰ= the Precipitation Reaction(Day 1)
- lab apron + safety goggles
- obtain 2 clean, dry 25ml graduated cylinder and one 250ml beaker.
- 25ml of NaCO₃(aq) in one cylinder & 25ml of CaCl₂(aq) in the other. Record volumes.
- Pour contents of both cylinders into the beaker. Observe. Record. Allow the contents of the beaker to sit undisturbed for 5 min to see what happens to the suspended soild particles. Meanwhile, do step 5.
- Get a piece of filter paper and put names on it with a pencil. Weigh and record the mass of it. Set up a filtering apparatus.
- Lightly wet the filter paper the funnel to keep it in place(using the wash bottle). Swirt the beaker to suspend the precipitate. Pour it carefully & slowly into the filter funnel. Use wash bottle to raise the remaining precipitate from the beaker.
- Rise the precipitate in the filter paper with wash bottle(to remove NaCl)
- Remove the wet filter paper and place it on a folded paper towel. Put filter paper(with CaCO₃) in the assigned location to dry.
- Clean up.
- Wash hands.
Part Ⅱ= Weighing the dried precipitate(Day 2)
- Weighing and recording the mass of dry filter paper + CaCO₃precipitate.
Reagent Disposal
Rinse all solutions down the smile with sufficient water. Solid go into the designed containers.
