Question

question 2: analyze and extend
part a
explain whether changing the ratio of baking soda and vinegar changes the amount of carbon dioxide produced. include the evidence you used to reach your conclusion.

Explanation:

Baking soda (sodium bicarbonate, $\ce{NaHCO_{3}}$) reacts with vinegar (acetic acid, $\ce{CH_{3}COOH}$) to produce carbon dioxide ($\ce{CO_{2}}$) via the reaction $\ce{NaHCO_{3} + CH_{3}COOH
ightarrow CH_{3}COONa + H_{2}O + CO_{2}\uparrow}$. The amount of $\ce{CO_{2}}$ depends on the limiting reactant. If the ratio of baking soda to vinegar is changed:

• Case 1: Vinegar is in excess initially (e.g., more vinegar than needed to react with all baking soda). Increasing baking soda (while vinegar remains excess) increases the moles of $\ce{NaHCO_{3}}$, so more $\ce{CO_{2}}$ is produced (since $\ce{NaHCO_{3}}$ is now the limiting reactant for the added amount). Decreasing baking soda (with excess vinegar) decreases $\ce{CO_{2}}$ production.
• Case 2: Baking soda is in excess initially (more baking soda than vinegar can react with). Increasing vinegar (while baking soda remains excess) increases $\ce{CO_{2}}$ (vinegar becomes the limiting reactant for the added amount). Decreasing vinegar (with excess baking soda) decreases $\ce{CO_{2}}$ production.
• Case 3: Stoichiometric ratio (exact amounts to react completely). Changing the ratio will make one reactant limiting, and the amount of $\ce{CO_{2}}$ will be determined by the limiting reactant (less than the maximum possible if one reactant is reduced).

Evidence: Experimental trials with different ratios (e.g., 1:1, 1:2, 2:1 of baking soda to vinegar by mass/volume) show that the volume of $\ce{CO_{2}}$ (measured via gas collection or balloon inflation) changes with the ratio. For example, adding more baking soda to a fixed amount of vinegar (until vinegar is used up) causes increasing $\ce{CO_{2}}$ until vinegar is limiting, after which $\ce{CO_{2}}$ production stops increasing.

In summary, changing the ratio changes the amount of $\ce{CO_{2}}$ because the reaction depends on the amount of each reactant, and the limiting reactant dictates the yield.

Answer:

Changing the ratio of baking soda and vinegar does change the amount of carbon dioxide ($\ce{CO_{2}}$) produced. This is because the reaction $\boldsymbol{\ce{NaHCO_{3} + CH_{3}COOH
ightarrow CH_{3}COONa + H_{2}O + CO_{2}\uparrow}}$ depends on the amount of each reactant (baking soda, $\ce{NaHCO_{3}}$; vinegar, $\ce{CH_{3}COOH}$). The amount of $\ce{CO_{2}}$ is determined by the limiting reactant (the reactant used up first).

• If one reactant is in excess (e.g., more vinegar than baking soda can react with), increasing the limited reactant (baking soda) increases $\ce{CO_{2}}$ production (and vice versa).
• If the ratio shifts to make a different reactant limiting (e.g., excess baking soda and limited vinegar), changing the ratio of the limiting reactant (vinegar) changes $\ce{CO_{2}}$ yield.

Evidence: Experimental trials with different ratios (e.g., varying the mass/volume of baking soda to vinegar) show that the volume of $\ce{CO_{2}}$ (measured via gas collection or balloon inflation) increases/decreases with the amount of the non - limiting reactant (until the limiting reactant switches). For example, adding more baking soda to a fixed volume of vinegar produces more $\ce{CO_{2}}$ until the vinegar is completely reacted (after which $\ce{CO_{2}}$ production stops increasing).

Thus, the ratio of baking soda to vinegar directly impacts $\ce{CO_{2}}$ production by altering which reactant is limiting and how much of the reactants are available to react.