The temperature change you observe when adding vinegar to a mixture of water, dish soap, and baking soda primarily results from the chemical reaction that occurs between the baking soda (sodium bicarbonate) and the vinegar (acetic acid). When vinegar is added to baking soda, a reaction takes place producing carbon dioxide gas, water, and sodium acetate. This reaction can be represented by the following chemical equation:
\[ \text{NaHCO}_3 (s) + \text{CH}_3\text{COOH} (aq) \rightarrow \text{CO}_2 (g) + \text{H}_2\text{O} (l) + \text{CH}_3\text{COONa} (aq) \]
Why More Vinegar Causes Greater Temperature Change:
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Increased Reaction Rate: When more vinegar is added, there is a greater concentration of acetic acid that can react with the baking soda. This results in more vigorous bubbling and the release of more carbon dioxide gas.
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Exothermic Process: The reaction between baking soda and vinegar is slightly exothermic, meaning it releases a small amount of heat as a byproduct. When you add more vinegar, more baking soda is able to react, producing more heat overall.
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Heat Capacity: The specific heat capacity of water means that the temperature of the entire mixture will change based on the energy released in the reaction. More reactants (vinegar and baking soda) lead to a greater overall release of energy, which can be observed as a larger temperature increase in the mixture.
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Concentration and Volume Effects: As you increase the volume of vinegar, the total amount of reactants increases, resulting in more vigorous and complete reactions, which contribute to a greater temperature change.
Conclusion:
In summary, adding more vinegar to the mixture increases the amount of reactants involved in the chemical reaction, leading to a more vigorous reaction that releases more heat. This results in a greater temperature change in the mixture.
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