Sodium Thiosulfate Reaction
eLearning
2009
Publication No. 91860
Rate of Reaction of Sodium Thiosulfate and Hydrochloric Acid
Rate Laws
Introduction
The purpose of this demonstration is to investigate the effect of sodium thiosulfate concentration on the rate of reaction of sodium thiosulfate with hydrochloric acid. The reaction, which produces solid sulfur, will be followed by measuring the time needed for the reaction mixture to become opaque. The results will be analyzed graphically to determine the order of reaction— the mathematical relationship between the reactant concentration and the rate.
Concepts
• Kinetics • Order of reaction • Rate law • Concentration
Materials
Hydrochloric acid solution, HCl, 2 M, 25 mL Sodium thiosulfate solution, Na2S2O3, 0.15 M, 150 mL Distilled or deionized water Beakers, 100-mL, 5 Graduated cylinders, 50- or 100-mL, 2 Graduated cylinders, 10-mL, 5 Overhead projector or light box Permanent marker Stirring rods Stopwatch or timer
Safety Precautions
Hydrochloric acid solution is corrosive to eyes and skin. It is moderately toxic by ingestion and inhalation. Sodium thiosulfate solution is a body tissue irritant. The reaction of sodium thiosulfate and hydrochloric acid generates sulfur dioxide gas, which is a skin and eye irritant. Perform this demonstration in a well-ventilated lab only. Avoid contact of all chemicals with eyes and skin. Wear chemical splash goggles, temperature-resistant gloves, and chemical-resistant apron. Please review current Material Safety Data Sheets for additional safety, handling, and disposal information.
Procedure
1. Label five 100-mL beakers 1–5 and clean the bottom of each beaker. 2. Draw a large “X” across the bottom on the outside of each beaker. Place the beakers on an overhead projector stage or a light box so that students can view the “X.” 3. Using separate graduated cylinders for the solution and water, measure and add the required amounts of 0.15 M sodium thiosulfate and distilled water to each
2009
Publication No. 91860
Rate of Reaction of Sodium Thiosulfate and Hydrochloric Acid
Rate Laws
Introduction
The purpose of this demonstration is to investigate the effect of sodium thiosulfate concentration on the rate of reaction of sodium thiosulfate with hydrochloric acid. The reaction, which produces solid sulfur, will be followed by measuring the time needed for the reaction mixture to become opaque. The results will be analyzed graphically to determine the order of reaction— the mathematical relationship between the reactant concentration and the rate.
Concepts
• Kinetics • Order of reaction • Rate law • Concentration
Materials
Hydrochloric acid solution, HCl, 2 M, 25 mL Sodium thiosulfate solution, Na2S2O3, 0.15 M, 150 mL Distilled or deionized water Beakers, 100-mL, 5 Graduated cylinders, 50- or 100-mL, 2 Graduated cylinders, 10-mL, 5 Overhead projector or light box Permanent marker Stirring rods Stopwatch or timer
Safety Precautions
Hydrochloric acid solution is corrosive to eyes and skin. It is moderately toxic by ingestion and inhalation. Sodium thiosulfate solution is a body tissue irritant. The reaction of sodium thiosulfate and hydrochloric acid generates sulfur dioxide gas, which is a skin and eye irritant. Perform this demonstration in a well-ventilated lab only. Avoid contact of all chemicals with eyes and skin. Wear chemical splash goggles, temperature-resistant gloves, and chemical-resistant apron. Please review current Material Safety Data Sheets for additional safety, handling, and disposal information.
Procedure
1. Label five 100-mL beakers 1–5 and clean the bottom of each beaker. 2. Draw a large “X” across the bottom on the outside of each beaker. Place the beakers on an overhead projector stage or a light box so that students can view the “X.” 3. Using separate graduated cylinders for the solution and water, measure and add the required amounts of 0.15 M sodium thiosulfate and distilled water to each