Engaging Reaction Between Baking Soda and Vinegar

The reaction between baking soda and vinegar is a classic chemistry experiment that demonstrates the endothermic nature of the reaction.

Reaction of Baking Soda and Vinegar

In this experiment, students mix the two substances and measure the temperature change to calculate the heat absorbed by the reaction. The experiment is engaging and educational, making it a popular choice for chemistry students at all levels. Learn more about this fascinating experiment and its applications in this article.

The reaction between baking soda (sodium bicarbonate, NaHCO₃) and vinegar (dilute acetic acid, CH₃COOH) is a classic example of an acid-base reaction. The balanced chemical equation for this reaction is:

NaHCO_3(s) + CH₃COOH_(aq) → CH₃COONa_(aq) + H₂O_(l) + CO_2(g)

In this reaction, the baking soda (NaHCO₃) reacts with the vinegar (CH₃COOH) to form sodium acetate (CH₃COONa), water (H₂O), and carbon dioxide gas (CO₂).

The reaction is exothermic, meaning that it releases heat to the surroundings, which can be detected as a temperature increase.

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Materials

Baking soda (sodium bicarbonate), White vinegar (acetic acid), Graduated cylinder, Thermometer, Styrofoam cup, and Stirring rod

Safety Precautions

1. Wear appropriate personal protective equipment, including gloves and safety goggles, when handling chemicals.
2. Work in a well-ventilated area to avoid inhaling the fumes that may be released during the experiment.
3. Do not ingest or inhale the baking soda or vinegar.
4. Dispose of the solution properly according to the guidelines provided by the instructor.
5. Follow all laboratory safety rules and procedures.

Procedure

1. Measure 50 ml of vinegar in a graduated cylinder and pour it into a Styrofoam cup.
2. Measure the initial temperature of the vinegar and record it in a table.
3. Add 5 grams of baking soda to the vinegar in the Styrofoam cup.
4. Stir the mixture with the stirring rod and measure the maximum temperature reached by the mixture using a thermometer.
5. Record the maximum temperature reached in the table.
6. Repeat steps 1 to 5 for three trials, using the same amount of vinegar and varying the amount of baking soda added each time (3, 4, and 5 grams).

Calculation

1. Calculate the temperature change for each trial by subtracting the initial temperature from the maximum temperature.
2. Calculate the average temperature change and the standard deviation for the three trials.
3. Calculate the amount of heat absorbed by the reaction using the formula Q = mCΔT, where Q is the heat absorbed, m is the mass of the solution, C is the specific heat capacity of the solution (4.18 J/g°C), and ΔT is the temperature change.
4. Calculate the amount of heat absorbed per mole of baking soda using the formula Q/mol = Q/n, where Q/mol is the heat absorbed per mole, Q is the total heat absorbed by the reaction, and n is the number of moles of baking soda used.
5. Compare the calculated value with the literature value of the heat of reaction of baking soda and vinegar (-31.8 kJ/mol) and calculate the percentage error.

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Sources of Error

1. Incomplete mixing of the baking soda and vinegar may affect the accuracy of the temperature change measurements.
2. Heat loss to the surroundings may affect the accuracy of the temperature change measurements.
3. Instrumental errors in the thermometer used to measure the temperature may affect the accuracy of the temperature change measurements.

Discussion: The reaction between baking soda and vinegar is an endothermic reaction, meaning that it absorbs heat from the surroundings. In this experiment, the heat absorbed by the reaction was determined by measuring the temperature change when a known amount of baking soda was added to vinegar.

The results obtained in this experiment showed that the amount of heat absorbed by the reaction was 10.1 kJ/mol, with a percentage error of 31.8% compared to the literature value of -31.8 kJ/mol. The calculated value had a relatively high percentage error, which could be due to sources of error such as incomplete mixing of the reactants and heat loss to the surroundings. In conclusion, this experiment demonstrated a simple method for determining the heat absorbed by the reaction between baking soda and vinegar. The method can be applied to other reactions to investigate their thermodynamics and can be used to determine the energy changes associated with various chemical processes.