High School Lab Report

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Title: Effect of Temperature on Reaction Rate

Submitted by: [Your Name]
Instructor: [Instructor's Name]
Date: [Submission Date]

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Abstract

This lab report examines the effect of temperature on the reaction rate between sodium thiosulfate and hydrochloric acid. The aim was to determine how varying temperatures influence the speed of this chemical reaction. By conducting experiments at different temperatures, we observed changes in reaction time and analyzed how temperature affects the rate of reaction. Results indicated a direct relationship between temperature and reaction rate, confirming the hypothesis that higher temperatures increase reaction rates.

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Introduction

The rate of a chemical reaction is influenced by several factors, including temperature, concentration, and the presence of catalysts. In this experiment, we focus on temperature as a variable affecting reaction rates. Sodium thiosulfate reacts with hydrochloric acid to form sulfur dioxide, water, and sodium chloride, and the rate at which this reaction occurs can be measured by the time taken for the reaction mixture to turn opaque due to the formation of sulfur.

Objective

To investigate the effect of temperature on the rate of reaction between sodium thiosulfate and hydrochloric acid.

Hypothesis

It is hypothesized that increasing the temperature will increase the rate of reaction. This is based on the principle that higher temperatures provide reactant molecules with more energy, leading to more frequent and energetic collisions.

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Materials and Methods

Materials

• Sodium thiosulfate solution (0.1 M)

• Hydrochloric acid solution (0.1 M)

• Distilled water

• Thermometer

• Beakers (100 mL)

• Measuring cylinders

• Stopwatch

• Conical flasks

• Ice bath

• Hot plate

Methods

1. Preparation: Prepare sodium thiosulfate and hydrochloric acid solutions at the desired concentrations. Ensure that all glassware is clean and dry.

2. Temperature Setting: Set up four different temperature conditions:

   • 10°C (Ice bath)

   • 20°C (Room temperature)

   • 30°C (Warm water bath)

   • 40°C (Hot plate)

3. Procedure:

   • Measure 50 mL of sodium thiosulfate solution into a conical flask.

   • Add 10 mL of hydrochloric acid to the flask and start the stopwatch immediately.

   • Observe the reaction and stop the stopwatch when the solution turns opaque.

   • Record the time taken for the solution to turn opaque.

   • Repeat the experiment three times for each temperature to ensure accuracy.

4. Data Collection: Record the time taken for each trial in a table.

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Results

Data Table

Temperature (°C)	Trial 1 (s)	Trial 2 (s)	Trial 3 (s)	Average Time (s)
10	98	101	95	98
20	53	56	55	54.7
30	32	30	31	31
40	22	21	23	22

Graphical Representation

A line graph is plotted to show the relationship between temperature and the average reaction time. The graph illustrates that as the temperature increases, the average reaction time decreases, indicating an increase in reaction rate.

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Discussion

The results confirm that temperature has a significant effect on the reaction rate between sodium thiosulfate and hydrochloric acid. As hypothesized, higher temperatures resulted in shorter reaction times. This can be explained by the increased kinetic energy of the reactant molecules at higher temperatures, leading to more frequent and effective collisions.

Analysis

• At 10°C, the reaction was the slowest, with an average time of 98 seconds. This suggests that the molecules had lower kinetic energy and fewer successful collisions.

• At 20°C, the reaction rate increased, with an average time of 54.7 seconds. This shows a noticeable improvement in reaction speed compared to the lower temperature.

• At 30°C, the average time further decreased to 31 seconds, indicating a faster reaction rate.

• At 40°C, the reaction was the fastest, with an average time of 22 seconds. This supports the hypothesis that higher temperatures significantly enhance reaction rates.

Sources of Error

Possible sources of error include:

• Variability in initial temperature settings.

• Inaccurate measurement of reactants.

• Inconsistent timing of the reaction endpoint.

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Conclusion

The experiment successfully demonstrated that temperature affects the rate of reaction between sodium thiosulfate and hydrochloric acid. Higher temperatures result in faster reactions, as evidenced by the decreasing reaction times with increasing temperature. This experiment reinforces the importance of temperature in chemical kinetics and provides a clear example of how temperature influences reaction rates.

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References

• "Chemistry: Principles and Reactions" by William L. Masterton and Cecile N. Hurley.

• "The Science of Chemistry: An Introduction" by Gary L. McLoud.

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