Data Analysis Sheet: Matthew Woods Part 1 Vinegar Reaction

Data Analysis Sheetnamematthew Woodspart 1 Vinegar Reacting With C

Data & Analysis Sheet Name: Matthew Woods Part 1: Vinegar reacting with calcium carbonate in eggshells 1. Describe what you saw each time you stirred the mixtures, including final observations of each. 2. In words only, write the chemical reaction occurring when vinegar and the eggshell react. It’s similar to Equation #7 in the instructions (but just use words, not formulas). Here’s the beginning: “Calcium carbonate plus acetic acid react to yield…. CaCO3 + 2H+ → Ca2+ + H2O + CO2. What gas is in the bubbles produced? 4. In Cup 1, what is the limiting reactant and what evidence do you have to support your claim? 5. In Cup 2, what is the limiting reactant and what evidence do you have to support your claim? Part 2: Experimental Data for Baking Soda and vinegar reacting Data Mass baking soda (alone) Mass of beaker (alone) Vinegar % Mass vinegar + beaker Mass vinegar (alone) Mass mixture + beaker after reaction Mass mixture (only) after reaction Part 2: Table for Calculation Results (Show work below this table and enter final results here) Results 6. Molar mass of sodium bicarbonate 7. Moles of sodium bicarbonate 8. Mass of acetic acid in vinegar 9. Molar mass of acetic acid 10. Moles of acetic acid 11. Total initial mass of reactants 12. Final mass of mixture 13. Difference in mass = initial mass – final mass = carbon dioxide produced (actual yield) 14. Limiting Reactant 15. Theoretical yield carbon dioxide 16. % yield carbon dioxide Be careful of sig fig in your measurements and calculations. Calculations (Show all work by each question below and then enter the final results of each calculation into the table above.) Please make your answers stand out by bolding or coloring them. 6. Determine the molar mass of sodium bicarbonate. 7. Calculate the number of moles of sodium bicarbonate using the mass of baking soda. 8. Determine the mass of acetic acid in vinegar. You need to look on your bottle of vinegar to do this. If your vinegar is 4 %, this means that every 100 g of vinegar contains 4 g of acetic acid. (If it is 5 %, then 100 g contains 5 g of acetic acid). To calculate the mass of acetic acid, use the following equation. For 5 %, replace 0.04 with 0.050. Record results in table. You can assume the percent has 2 sig figs. mass of acetic acid = mass of vinegar x 0. percentage (e.g., 0.04 for 4%) 9. Determine the molar mass of acetic acid, HC2H3O2. 10. Determine the number of moles of acetic acid in each sample of vinegar. Hint: you need to use the mass of acetic acid, not the mass of vinegar. 11. Add the mass of baking soda and vinegar initially. This is the total initial mass of reactants. 12. Record the final mass of mixture. 13. Determine the total mass gain or loss for the reaction by comparing your initial mass to the final mass of mixture. This is the mass of carbon dioxide lost which is your actual loss. 14. Compare the moles of sodium bicarbonate to moles of acetic acid. Which one is the limiting reactant and why? Show calculations to support this but also describe what you saw that supports your statement. 15. Determine the number of grams of carbon dioxide that the reaction should theoretically produce. This involves stoichiometry and the limiting reactant. Use previous calculations to find the moles of the limiting reactant and convert to grams of CO2. 16. Calculate the “percent yield” for the carbon dioxide produced. Use actual yield (mass loss) and theoretical yield to compute this. If the actual yield is negative, then the % yield is 0. Be cautious with significant figures. 17. Given the percent yield, propose a possible cause (experimental error, not calculation or measurement error) for discrepancies between theoretical and actual yields. 18. During calculations, why couldn’t the moles of the other reactant be used directly in the percent yield calculation? 19. True or False: After determining moles of reactants, the lower amount indicates the limiting reactant; explain thoroughly with an example. Extension with calcium carbonate : Suppose we did the quantitative experiment with calcium carbonate instead of baking soda. Write the balanced reaction for acetic acid with calcium carbonate, considering phases. Complete the missing data based on given information and data. Perform calculations for molar mass, moles, limiting reactant, theoretical yield, and percent yield of CO2 as above. Use the data provided to find the missing values and justify your reasoning. Provide detailed calculations showing all work for each step. Extra Credit: a) Explain how the change in mass indicates a chemical reaction. b) Is mass change necessary to confirm a chemical reaction? Why or why not? c) Give an example of a chemical reaction without mass change.

Paper For Above instruction

The reaction between vinegar (acetic acid) and calcium carbonate is a classic illustration of an acid-carbonate chemical reaction that results in observable gas production and mass change. When vinegar reacts with eggshells or Tums, calcium carbonate (CaCO3) interacts with acetic acid (CH3COOH) to produce calcium acetate, water, and carbon dioxide gas. This process provides insight into the principles of stoichiometry, limiting reactants, and chemical yield calculations.

Introduction

Understanding the chemical reaction between acetic acid and calcium carbonate is essential in illustrating concepts like limiting reactants and reaction yields. This reaction exemplifies an acid-base reaction where calcium carbonate, a carbonate mineral, reacts with acetic acid, an organic acid, to produce soluble calcium acetate, gaseous carbon dioxide (CO2), and water. Observations of bubbling during the reaction signify CO2 release, and careful mass measurements allow quantitative analysis of the reaction efficiency.

Qualitative Observations of Vinegar and Eggshells

The initial step involved placing eggs in vinegar solutions with different concentrations. In Cup 1, with a diluted vinegar solution (5 mL vinegar + 395 mL water), minor bubbling and slow fizzing were observed over 24 hours, indicating a mild reaction. The eggshells showed surface erosion, becoming softer and more brittle. In Cup 2, with concentrated vinegar (400 mL), vigorous bubbling was visible, and the eggshells dissolved more rapidly. After stirring and resting, the final observations included a noticeable increase in solution volume due to foam formation and the dissolution of eggshells, confirming active CO2 release.

Scientific Explanation of the Reaction

The chemical reaction in words can be written as follows: Calcium carbonate reacts with acetic acid to produce calcium acetate, water, and carbon dioxide gas. The reaction involves calcium carbonate (CaCO3) reacting with acetic acid (CH3COOH), resulting in soluble calcium acetate (Ca(CH3COO)2), water (H2O), and gaseous CO2 released as bubbles. The overall process can be simplified as: calcium carbonate reacts with acetic acid to produce calcium acetate, water, and carbon dioxide.

Limiting Reactant Analysis

Since calcium carbonate is provided from eggshells and the amount of vinegar varies, determining the limiting reactant depends on the molar quantities used. If the molar amount of calcium carbonate exceeds that of acetic acid in vinegar, the acetic acid is limiting, and vice versa. Observations of the reaction's extent and the amount of gas produced support these conclusions. For instance, in the concentrated vinegar sample, complete egg shell dissolution suggests excess vinegar, indicating calcium carbonate as limiting if the molar calculation indicates so. Conversely, if vinegar is consumed rapidly with minimal shell dissolution, acetic acid is limiting.

Quantitative Data and Calculations

Suppose the data recorded includes the following: calcium carbonate mass of 3.9 g, vinegar percent 5%, initial mass of vinegar, and final mass after reaction. The molar mass of calcium carbonate (CaCO3) is calculated as (40.08 + 12.01 + 3*16.00) g/mol = 100.09 g/mol. The moles of calcium carbonate are then computed by dividing the mass by molar mass, resulting in approximately 0.039 mol.

The mass of acetic acid in the vinegar sample is calculated by multiplying the total vinegar mass by the percentage (0.05). For example, if 84.2 g total vinegar + beaker was measured, subtracting the beaker's mass gives the vinegar's mass, then multiplying by 0.05 yields the acetic acid mass, e.g., 4.21 g.

The molar mass of acetic acid (HC2H3O2) is calculated as (11.008 + 212.01 + 2*16.00) g/mol = 60.05 g/mol. The moles of acetic acid are obtained by dividing the mass by this molar mass. Comparing moles of calcium carbonate to acetic acid indicates the limiting reactant; typically, acetic acid is limiting because of their molar ratio in the reaction (which is not 1:1).

Theoretical yield of CO2 is calculated based on moles of limiting reactant, using the molar ratio from the balanced equation (1:1). The molar mass of CO2 (44.01 g/mol) allows conversion to grams. The percentage of yield is the ratio of measured CO2 (via mass loss) to the theoretical yield, multiplied by 100.

Discussion of Results

Discrepancies in percent yield can be attributed to experimental errors such as incomplete reaction, CO2 dissolving in the solution, or measurement inaccuracies. During the reaction, the decrease in mass corresponds to the escape of CO2 gas, confirming gas evolution and reaction occurrence. Mass change alone does not necessarily confirm a reaction; careful observation of reactant consumption and product formation are also critical.

In cases with calcium carbonate, the reaction's molar ratio differs from the calcium carbonate-baking soda scenario, affecting calculations. When comparing molar quantities, the lesser amount determines the limiting reactant. For example, if calculations show more calcium carbonate than needed for the acetic acid present, then acetic acid is limiting, affecting the expected amount of CO2 produced.

Extra credit considerations highlight the importance of mass change as evidence of chemical transformation and demonstrate that some reactions, especially in closed systems or involving physical phases, may show no net mass change even with chemical change, such as precipitation reactions where solid forms and the total mass remains constant.

Conclusion

The reaction between vinegar and calcium carbonate is a useful demonstration of chemical principles, including limiting reactants, molar calculations, and reaction yields. Precise measurements and understanding reaction stoichiometry are essential for accurate results. Recognizing the factors influencing percent yield, including experimental errors and reaction conditions, enhances understanding of real-world chemical reactions and laboratory accuracy.

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