温度依存性

Measure 50.5 g of iron nitrate nonahydrate and place it in a 250-mL Erlenmeyer flask using a powder funnel. Add 175 mL of deionized water and stir until homogeneous. Add another 75 mL of deionized water and continue stirring until the solution appears homogeneous again. Transfer the final solution into a labeled polyethylene bottle and store it capped at the back of the instructor's hood.

Wear a lab coat, chemical splash goggles, and gloves before handling iron (III) nitrate nonahydrate. These items protect against chemical exposure and splashes during the preparation of the 0.5 M solution. Always ensure appropriate safety equipment is in place before beginning any chemical preparation work.

Each workstation requires a hotplate, support rod with medium 3-prong clamp and thermometer clamp, gas pressure sensor device, 20-mL volumetric pipette, pipette controller, beaker assortment (50-mL, 100-mL, three 400-mL, and one 600-mL), Büchner flask, thermometer, rubber stopper, syringe, and stopcock. A 125-mL wash bottle filled with deionized water should also be available at each station.

Stirring ensures the iron nitrate nonahydrate powder dissolves completely and the solution becomes homogeneous. The mixture is stirred after adding the initial 175 mL of water, and again after adding the final 75 mL of water. Continuous stirring on a stir plate promotes uniform distribution of solute throughout the solvent.

Fill an insulated cooler with crushed or chipped ice and place it centrally. Set up a labeled waste container for aqueous iron solutions in the hood. Place a 1-L bottle of 3 wt% hydrogen peroxide in the central hood. Ensure gas pressure sensor devices are charged and working before distribution. Confirm all vacuum sources have silicone tubing attached.

Transfer the homogeneous solution into a labeled 250-mL polyethylene bottle and cap it tightly. Store the capped bottle at the back of the instructor's hood until just before the lab begins. This storage method protects the solution from contamination and maintains its stability until use.

Use a top-loading balance to measure 50.5 g of iron nitrate nonahydrate, a graduated cylinder to measure deionized water volumes, a 250-mL Erlenmeyer flask for mixing, and a powder funnel for transferring the solid. A stir bar and stir plate facilitate homogenization. A 250-mL polyethylene bottle stores the final solution.