Record your lab results in the table below. mass of Erlenmeyer flask (g) 88.000

Question

Record your lab results in the table below.

mass of Erlenmeyer flask (g) 88.000 g

mass of flask 20 mL water (g) 108.155 g

mass of flask water Alka Seltzer right after mixing (g) 110.155 g

mass of flask water Alka Seltzer after the reaction (g) 110.155 g

mass of flask water Alka Seltzer after releasing gas (g) 109.545 g

pressure inside the closed flask after the reaction (atm) 2.94 atm

pressure inside the open flask (atm) 1.00 atm

Data Analysis

Calculate the combined mass of the reactants, water and Alka Seltzer, before the reaction. 22.155 g

Calculate the mass of the contents of the flask after the reaction. 22.155 g

Compare the before and after-the-reaction masses.

Calculate the percent deviation between the initial mass and the mass measured after the reaction. The masses stayed the same both before and after the chemical reaction. 0% deviation

Calculate the mass of the gas formed in the reaction between water and Alka Seltzer. ***** Need help with this question.

According to the Law of Conservation of Mass, matter cannot be created nor destroyed. Do your results from this experiment agree with this law? Yes they do.

Conclusions

What is the gas formed in the water and Alka Seltzer reaction? bicarbonate and citric acid, which reacted to the water to form carbon dioxide bubbles.

Why does the flask have to be closed during the water and Alka Seltzer reaction? the pressure could escape and we would not be able to see a pressure change.

Acid–base reactions are hard to observe because they usually do not provide any visual cues. In this lab, you used a thermometer to determine that a reaction occurred between vinegar and sodium hydroxide. How could you detect the changes caused by this reaction in a classroom laboratory if you did not have access to a thermometer? The presence of bubbles indicating a gas forming, and also by touching the flask to feel how warm it may be.

Suppose a student performed a precipitation reaction and isolated his precipitate. Given the data in the table below, what was the mass of the reactants before the reaction? Assume no mass loss during the isolation of the precipitate.

mass of empty flask 54.275 g

mass of precipitate 1.240 g

mass of flask and contents after isolating precipitate 122.488 g

Mass of reactants before reaction: 69.433 g

The Law of Conservation of Mass states that matter is neither created nor destroyed in a chemical reaction. How do you explain iron nails getting heavier as they rust?

**** Need help with this question

Explanation / Answer

*Since, you already answered the other parts, I am answering only the questions you needed help with*

1) Calculate the mass of the gas formed in the reaction between water and Alka Seltzer.

Answer: The reaction does not create mass. It creates pressure. The mass did not change.

2)The Law of Conservation of Mass states that matter is neither created nor destroyed in a chemical reaction. How do you explain iron nails getting heavier as they rust?

Answer: The nail getting heavier when rust is present is due to the bond created when water molecules bonds to the surface creating rust. There is no growth of mass, yet a gain in mass due to the bond. If no water were present, the nail would not have an opportunity to corrode.

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