We recently did the baking soda vinegar reaction to determine how much acetic acid was in 15 mL of vinegar. What is the minimum amount of baking soda that you could do to inure an accurate result? Thank you so much for your help!
The question is far to general. How much accuracy do you want? What size buret are you using? Assuming you are using a 50 mL buret and you dilute the raw acetic acid by a factor of 100, it will take about 3.1 g NaHCO3 for an accuracy of better than 1 part per thousand variation (which doesn't count the error made in the dilution). That dilution probably can't be done with better than 1 part per thousand. So the molarity of the final determination should be no worse than 2 ppt (parts per thousand) error. When I taught quant I gave students a grade of 100 for a determination that close.
DrBob222
We were given 15 mL of white vinegar and baking soda and we were told to find how much acetic acid was in those 15 mL of vinegar- which we did by performing the reaction, calculating the mass of CO2 that escaped, and then using the ratio to determine how much acetic acid was in the vinegar. A follow up question was "what is the minimum amount of baking soda that can be used and still provide and accurate result."
I understand. I know you don't think I answered your question but I did the best I could without enough information. You must define accuracy. How accurate is "an accurate result"? Is that 1 ppt, 1%, 10% 50%, just what. From your response I assume you weighed the CO2. What kind of a balance did you use? More specifically, does the balance weigh to the nearest 0.01 gram or is it better than that? I'm sorry for being so picky but good analytical chemists are picky.
To determine the minimum amount of baking soda required for an accurate result in the baking soda vinegar reaction, we need to understand the stoichiometry of the reaction.
The balanced chemical equation for the reaction between baking soda (sodium bicarbonate, NaHCO3) and vinegar (dilute acetic acid, CH3COOH) is:
NaHCO3 + CH3COOH -> CO2 + H2O + CH3COONa
From the balanced equation, we can see that one mole of baking soda reacts with one mole of acetic acid to produce one mole of carbon dioxide, one mole of water, and one mole of sodium acetate.
Now, let's calculate the molar amount of acetic acid in 15 mL of vinegar.
To do this, we need to know the concentration of acetic acid in the vinegar solution. Typically, vinegar has a concentration of around 5% acetic acid by volume. Since 5% means 5 mL of acetic acid in 100 mL of vinegar, we can calculate the molar amount of acetic acid:
(5 mL / 100 mL) x (1 mole / 60 mL) = 0.00833 moles of acetic acid
According to the stoichiometry of the reaction, we need the same number of moles of baking soda to react with the acetic acid. Therefore, we need a minimum of 0.00833 moles of baking soda.
To convert moles to grams, we need to know the molar mass of baking soda, which is:
NaHCO3 = 22.99 g/mol (sodium) + 1.01 g/mol (hydrogen) + 12.01 g/mol (carbon) + 16.00 g/mol (oxygen) = 84.00 g/mol
Now, let's calculate the minimum amount of baking soda in grams:
0.00833 moles x 84.00 g/mol = 0.6999 grams (rounded to 0.7 grams)
Therefore, the minimum amount of baking soda required to ensure an accurate result in this experiment would be approximately 0.7 grams.