Rates Of Reaction - GCSE Science Required Practical

Summary

This video demonstrates an experiment measuring the reaction rate between sodium thiosulfate and hydrochloric acid. By observing the time it takes for a cloudy yellow precipitate to form, viewers learn how varying concentrations of sodium thiosulfate affect the reaction time. The experiment highlights the relationship between concentration and reaction rates, illustrating that higher concentrations lead to faster reactions. The clear, step-by-step procedure emphasizes safety and accuracy in measurements, while the results suggest a curve that indicates a decreasing reaction time with increased concentration. This engaging exploration provides valuable insights into the fundamentals of chemical kinetics.

Takeaways

• 😀 The video demonstrates how to measure the rate of a chemical reaction using sodium thiosulfate and hydrochloric acid.
• 🧪 When sodium thiosulfate reacts with hydrochloric acid, it produces an insoluble precipitate of sulfur, changing the solution's color.
• ⏱️ The experiment times how long it takes for the yellow cloudy color to obscure a marked cross beneath the reaction vessel.
• 📏 The initial concentration of sodium thiosulfate used is 40 grams per decimeter cubed, measured accurately at 50 cm³.
• 💧 Diluting sodium thiosulfate with distilled water allows for varying concentrations while maintaining a constant total volume.
• ⚡ A higher concentration of sodium thiosulfate increases the likelihood of particle collisions, speeding up the reaction rate.
• 🔬 Safety precautions are highlighted, including avoiding inhalation of sulfur dioxide fumes produced during the reaction.
• 📊 Multiple trials for different concentrations provide data to analyze the relationship between concentration and reaction time.
• 📉 As the concentration of sodium thiosulfate increases, the time taken for the precipitate to form decreases, indicating a faster reaction rate.
• 📈 A graph of concentration against reaction time reveals a curved line, demonstrating the inverse relationship between concentration and time.

Q & A

What is the purpose of the experiment described in the video?

The purpose of the experiment is to measure the rate of a chemical reaction between sodium thiosulfate and hydrochloric acid, observing how varying the concentration of sodium thiosulfate affects the reaction time.

What observable change indicates that the reaction has occurred?

The reaction produces an insoluble precipitate of sulfur, causing the solution to turn from clear and colorless to a yellow, cloudy appearance, which obscures a cross drawn on paper beneath the reaction vessel.

How is the concentration of sodium thiosulfate manipulated in the experiment?

The concentration of sodium thiosulfate is varied by diluting it with distilled water while keeping the total volume constant at 50 centimeters cubed.

What measurements are taken during the experiment?

Measurements include the volume of sodium thiosulfate (50 centimeters cubed) and hydrochloric acid (10 centimeters cubed), as well as the time taken for the precipitate to form and obscure the cross.

What initial concentration of sodium thiosulfate is used, and what is the recorded reaction time?

The initial concentration of sodium thiosulfate used is 40 grams per decimeter cubed, with a recorded reaction time of 27.44 seconds for the first trial.

What is the significance of reducing the concentration of sodium thiosulfate?

Reducing the concentration decreases the number of sodium thiosulfate particles in the solution, leading to fewer collisions and, theoretically, a slower reaction rate.

What precautions are mentioned regarding safety during the experiment?

It is advised to avoid inhaling sulfur dioxide fumes produced during the reaction, as they can cause coughing.

What kind of graph is plotted to analyze the results of the experiment?

A graph is plotted with the concentration of sodium thiosulfate on the x-axis and the reaction time on the y-axis, showing a curve rather than a straight line.

What conclusion can be drawn from the experiment regarding the relationship between concentration and reaction time?

The experiment concludes that as the concentration of sodium thiosulfate increases, the reaction time decreases, indicating a non-linear relationship.

How many trials are suggested to ensure reliable results?

It is suggested to repeat the experiment multiple times to obtain average times for each concentration, ensuring the results are reliable.