(105) Limiting Reactant Lab: Aluminum + Copper(II) Chloride

Lab Overview

  • Focus on limiting reactants in chemical reactions.

  • Objective: To compare theoretical yield with actual yield and calculate percent yield.

Materials Used

  • Balance: To measure the mass of reactants and products.

  • Beaker: Where the reaction between aluminum foil and copper(II) chloride occurs.

  • Copper(II) Chloride (CuCl2): The reaction partner with aluminum, has a formula weight of 170.49 g/mol.

  • Filter Paper: Used to separate solid product from the solution.

  • Hydrochloric Acid (HCl): Added as a catalyst to enhance the reaction by overcoming aluminum's protective coating.

Procedure

Step 1: Preparing Reactants

  • Weighing Filter Paper: 1.49 grams.

  • Aluminum Foil: 0.60 grams is used for the reaction.

  • Copper(II) Chloride: Added carefully; total weight is measured at 6.35 grams.

Step 2: Reaction Setup

  • Add water to copper(II) chloride in the beaker to help it dissolve. Stir until dissolved.

  • Add 2 drops of hydrochloric acid to facilitate the reaction.

  • Crumple aluminum foil slightly and add it to the solution to initiate the reaction.

Step 3: Observations During Reaction

  • Chemical change is observed: heating occurs, and noticeable reactions are noted (e.g., gas evolution, color change).

Step 4: Separation of Solid Product

  • After the reaction, allow the mixture to settle.

  • Set up filtration apparatus with filter paper to collect solid product left after reaction.

  • Rinse out any remaining solid with deionized water to ensure complete collection.

Final Steps

  • Remove the filter paper with solid product after drainage.

  • Allow the solid to dry overnight.

  • Record the final mass to complete the data table for analysis.

Important Concepts

  • Limiting Reactant: The component in a reaction that will be completely consumed first, determined by molar ratios.

  • Theoretical Yield: The amount of product expected based on stoichiometric calculations.

  • Percent Yield:

    [ ext{Percent Yield} = \left( \frac{\text{Actual Yield}}{\text{Theoretical Yield}} \right) \times 100 ]This measures the efficiency of a reaction.

Questions for Lab Reflection

  • Write and balance the chemical equation for the reaction between aluminum and copper(II) chloride.

  • Discuss the observed signs of a chemical reaction during the experiment.

  • Calculate the percent yield based on collected data.

The limiting reactant in the reaction between aluminum and copper(II) chloride is determined by the reactant that will be completely consumed first based on their molar ratios. In this specific experiment, aluminum (0.60 grams) is likely to be the limiting reactant if it is used in a smaller molar quantity compared to the copper(II) chloride (6.35 grams). This means that once the aluminum is consumed, the reaction will stop even if there is excess copper(II) chloride remaining.