Criteria B PG - 23 Chemistry Lab Procedure PDF
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This document describes a chemistry lab procedure for investigating the effect of changing temperature and concentration on the equilibrium of a cobalt chloride solution. The experiment details the materials, procedure, and safety precautions to follow. The lab work would likely involve observation of color changes as temperature and concentration are manipulated. The document does not appear to be a past paper.
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## CRITERIA B: PG - 23 ### Independent Variable: Temperature - I will change the temperature because it directly affects the equilibrium position. ### Dependent Variable: Color of the solution - I will measure the color of the solution because it indicates shifts in equilibrium, allowing us to o...
## CRITERIA B: PG - 23 ### Independent Variable: Temperature - I will change the temperature because it directly affects the equilibrium position. ### Dependent Variable: Color of the solution - I will measure the color of the solution because it indicates shifts in equilibrium, allowing us to observe whether the reaction favors reactants (pink) or products (blue). ### Controlled Variable: Volume of solution - I will control the volume of the solution because it will ensure fair & accurate results on the impact of temperature. ### Independent Variable: Concentration - I will change the concentration by adding HCl or water to see how the equilibrium shifts. ### Dependent Variable: Color of the solution - I will measure the color of the solution because it will help understand how chloride concentration affects the equilibrium. ### Controlled Variable: Volume of solution - I will control the volume of the solution because it will ensure fair & accurate results on the impact of concentration. ### Safety Measures: 1. Wear safety goggles and gloves when handling chemicals. 2. Use the hot plate cautiously to avoid burns. 3. Handle hydrochloric acid with care, as it is corrosive. ### Materials: 1. Cobalt(II) chloride hexahydrate powder 2. Distilled water 3. Beakers 4. 2 mol dm⁻³ hydrochloric acid 5. Test Tubes 6. Dropper 7. Hot water bath 8. Ice bath 9. A glass rod ## Procedure ### 1. Establishing Initial Equilibrium: - Gather all the materials - Add 1 mass of Cobalt chloride in a beaker - Add 50 cm³ of Distilled water - Observe and record the color of the solution - Add 10 cm³ of hydrochloric acid - Allow the solution to equilibrate at room temperature for a few minutes. - Observe and record the color of the solution ### 2. Altering the Equilibrium - Method 1: Temperature - Divide the equilibrated solution into three test tubes. - Place one test tube in a hot water bath, the other in a room temperature beaker and the last one in an ice water bath. - Wait for a few minutes - Observe and record the color changes in both test tubes after a few minutes ### 3. Altering the Equilibrium - Method 2: Concentration - In the test tube containing the room temperature solution, gradually add more 2 mol dm⁻³ hydrochloric acid using a dropper, increasing the concentration - Observe the color change as the chloride concentration increases, shifting the equilibrium towards blue - Next, dilute the same solution by adding distilled water dropwise, reducing the concentration. The color should shift back towards pink as the equilibrium favors the reactants.
