OL Lab 7: Ideal Gas Law

Learning Objectives

The objectives of this lab are designed to help students integrate theoretical and practical knowledge of gases, acids, and bases. The specific goals are to:

• Explain the physical principles of temperature and the concept of absolute zero.

• Explore the relationship between pressure, volume, and temperature through gas thermometry.

• Apply the Ideal Gas Law in scientific and real-world scenarios.

• Identify acids and bases commonly encountered in daily life.

• Define pH, classify acids and bases according to the pH scale, and connect these concepts to biological and chemical systems.

• Apply the Brønsted-Lowry definition of acids and bases to chemical reactions.

• Describe the amphoteric nature and self-ionization ability of water.

• Calculate the pH of strong acids and bases in aqueous solutions.

• Determine the likelihood of a neutralization reaction occurring.

• Evaluate the outcomes of simple acid–base interactions.

Introduction

The Ideal Gas Law plays a critical role in understanding how gases behave under varying conditions. This lab simulation introduced the concepts of temperature, absolute zero, and their significance in the field of thermodynamics. Students were able to manipulate variables such as temperature and pressure in order to observe how gases respond to different conditions. By doing so, they defined absolute zero and gained practical experience with the Ideal Gas Law.

The relevance of these experiments extends beyond chemistry classrooms. For instance, medical professionals rely on gas law principles to safely manage compressed gases in hospitals and to maintain proper conditions for organ transportation. This illustrates how chemistry integrates into life-saving practices.

The second part of the lab centered on acids and bases. Students explored how acidic and alkaline substances influence pH levels, applied the Brønsted-Lowry definitions, and examined neutralization reactions. These concepts are highly applicable to both healthcare and industrial practices, where maintaining balanced pH is critical to stability and safety.

Part 1: Complete Labster Lab – Ideal Gas Law: Apply to Save a Life

Purpose

The purpose of this experiment was to investigate the Ideal Gas Law and examine the interrelationship among pressure, volume, and temperature. In addition, the lab highlighted the importance of establishing an absolute temperature scale and identifying absolute zero as a constant reference point in thermodynamics.

Observations

The following observations were recorded during the simulation:

Question 3

If the pressure of a fixed volume of gas decreased in a sealed container, what variable would you think changed? Did this variable increase or decrease?

When the pressure in a sealed container decreases, the temperature must have decreased. This is because, according to the Ideal Gas Law, pressure is directly proportional to temperature when volume is held constant.

Question 4

Why is it important to convert into units of Kelvin before using the Ideal Gas Law?

It is important to convert temperatures to the Kelvin scale because Kelvin is an absolute scale without negative values. The scale begins at absolute zero, ensuring calculations are accurate and proportional when applying the Ideal Gas Law. Using Celsius or Fahrenheit could result in miscalculations due to arbitrary zero points.

Question 5

Using what you learned in this simulation, explain why compressed gas cylinders, such as those found in the hospital, typically contain a warning to not leave in sunlight or expose to heat.

Compressed gas cylinders are highly sensitive to heat. When exposed to high temperatures, the gas molecules inside gain kinetic energy, which increases the internal pressure. Elevated pressure can lead to safety hazards, including cylinder rupture or explosions. This is why hospitals and laboratories enforce strict storage guidelines for gas cylinders, emphasizing the need to keep them in cool and controlled environments.

Part 2: Complete Labster Lab – Acids and Bases

Question 1

In your own words, describe how to determine which substance acts as an acid and which substance acts as a base in the forward direction of the following reaction: H₂S + H₂O ⇌ H₃O⁺ + HS⁻

In this reaction, the substance donating a proton (H⁺) is the acid, while the substance accepting a proton is the base. Here, H₂S donates a proton and becomes HS⁻, making it the acid. Water (H₂O) accepts the proton to form H₃O⁺, making it the base. This aligns with the Brønsted-Lowry definition.

Question 2

Predict the two products of the following neutralization reaction and label each product using acid/base terminology: HCl + RbOH → ?

The reaction produces RbCl (a salt) and H₂O (water). Neutralization reactions typically follow the rule:

Acid + Base → Salt + Water

In this case:

• HCl is the acid.

• RbOH is the base.

• RbCl is the resulting salt.

• H₂O is the neutralizing product.

Question 3

In your own words, describe the relationship between proton (H⁺) concentration and pH.

The concentration of hydrogen ions (H⁺) in solution is inversely related to pH. As the H⁺ concentration increases, the pH decreases, indicating a more acidic solution. Conversely, as the H⁺ concentration decreases, the pH rises, making the solution more basic. This logarithmic relationship means small changes in H⁺ concentration significantly affect pH levels.

Question 4 – Reflection

Consider what you learned from this simulation. Reflect on three to four key concepts that you learned in this lab exercise. How could the lessons learned in this virtual lab relate to a real-world situation in the community/world or your future career? Be specific in your answer (this should require 5–10 sentences).

This lab reinforced the significance of both gas laws and acid–base chemistry in practical contexts. One key takeaway was the critical role of pH balance in maintaining biological systems. For example, human blood requires a tightly regulated pH of approximately 7.35–7.45, and any deviation can lead to severe health consequences. Understanding this principle is essential in medical careers, especially when preparing IV fluids or monitoring patient conditions.

Another key insight was the importance of neutralization reactions in both industrial and healthcare practices. These reactions are widely used in wastewater treatment and in neutralizing stomach acid with antacids.

Finally, the Ideal Gas Law demonstrated how temperature and pressure management is crucial for safety. For instance, compressed gas cylinders in hospitals must be handled carefully to prevent dangerous pressure buildup. As a future healthcare professional, I will apply these lessons to ensure patient safety, proper medication preparation, and adherence to hospital safety protocols.

Grading Rubric

References

Atkins, P., & de Paula, J. (2017). Atkins’ physical chemistry (11th ed.). Oxford University Press.

Labster. (n.d.). Acids and Bases. Labster Virtual Lab Simulation.

Labster. (n.d.). Ideal Gas Law: Apply to save a life. Labster Virtual Lab Simulation.

CHEM 120 Week 4 Lab: Ideal Gas Law and Acids and Bases

Zumdahl, S. S., & Zumdahl, S. A. (2020). Chemistry: An Atoms First Approach (3rd ed.). Cengage Learning.