Question

Which of the following statement(s) describes the pressure of a gas? a. the force of the gas particles on the walls of the container b. the number of gas particles in a container c. the volume of the container d. \(3.00 \mathrm{~atm}\) e. 750 torr

Short answer

Statements 'a', 'd', and 'e' describe the pressure of a gas.

Step-by-step solution

Understand the Definitions

Review the definition of pressure. Pressure is defined as the force exerted by gas particles colliding with the walls of the container per unit area. It is often measured in units such as atmospheres (atm) or torr.

Analyze Each Statement

Go through each of the given statements to determine whether they meet the definition of pressure.

Step 2a: Analyze Statement 'a'

Statement 'a' mentions 'the force of the gas particles on the walls of the container'. This aligns with the definition of pressure, so it describes pressure of a gas.

Step 2b: Analyze Statement 'b'

Statement 'b' refers to 'the number of gas particles in a container'. This represents the quantity of gas molecules, not pressure.

Step 2c: Analyze Statement 'c'

Statement 'c' refers to 'the volume of the container'. Volume is the space the gas occupies and is not a direct measure of pressure.

Step 2d: Analyze Statement 'd'

Statement 'd' gives a specific pressure value '3.00 atm'. This is a clear expression of the gas pressure.

Step 2e: Analyze Statement 'e'

Statement 'e' gives a specific pressure value '750 torr'. This also directly describes the pressure.

Conclusion

Identify which statements describe the pressure based on the analysis: statements 'a', 'd', and 'e'.

Key concepts

Definition of Gas Pressure

Gas pressure is a fundamental concept in chemistry and physics. It refers to the force gas particles exert when they collide with the walls of their container. These collisions happen continuously and randomly. As a result, the concept of gas pressure emerges.

The formula for pressure is given by: \[ P = \frac{F}{A} \] where - P represents the pressure, - F is the force exerted by the gas particles, - A is the area of the container walls the force is acting upon.

This definition helps to understand why increasing the number of particles or their kinetic energy increases the pressure inside the container.

Units of Pressure

Pressure can be measured using various units, and understanding these units is crucial. The most common units include:

• Atmosphere (atm): A standard unit for measuring pressure, often used in meteorology and scuba diving.
• Torr: Named after Evangelista Torricelli, this unit is equal to 1/760 of an atmosphere.
• Pascals (Pa): The SI unit of pressure where 1 Pa is equal to one newton per square meter.
• Bar: Another unit of pressure, with 1 bar being very close to the atmospheric pressure at sea level.

Knowing these units and how to convert between them is essential for solving problems related to gas pressure.

Gas Particles Collisions

Understanding the behavior of gas particles is key to grasping gas pressure. Gas particles move constantly and collide with each other and with the walls of their container.

These collisions are elastic, meaning that there is no loss of kinetic energy. The force exerted by these collisions on the container walls contributes to the pressure of the gas. Important points include:

• Higher temperature increases the kinetic energy of particles, leading to more frequent and forceful collisions.
• More particles in the same volume lead to more collisions, increasing the pressure.
• Reducing the volume of the container while keeping the number of particles the same also increases collision frequency, and thus pressure.

This dynamic behavior of gas particles underlies the concept of gas pressure.

Force on Container Walls

The force exerted by gas particles on the container’s walls is a direct manifestation of gas pressure. Each collision imparts a tiny force on the wall. When many particles collide, these small forces add up to create a measurable pressure.

Some key aspects to remember are:

• Pressure is directly proportional to the number of particles and their average kinetic energy.
• The force per unit area increases if either the number of particles, the energy of collisions, or the temperature increases.

This relationship explains phenomena like why a balloon inflates more when you add more air or when it is exposed to higher temperatures.

Measuring Pressure in atm and torr

Measuring gas pressure accurately is essential for many applications ranging from scientific research to everyday cooking. Two main units often used are atmospheres (atm) and torr.

• Atmospheres (atm): One atmosphere is defined as the pressure exerted by 1 kilogram of force per square centimeter. It is the average pressure at sea level on Earth.
• Torr: Named after Torricelli, the inventor of the barometer, this unit is widely used in scientific laboratories. One atmosphere is equivalent to 760 torr.

Understanding these units allows one to measure and express gas pressure accurately in different contexts, aiding in consistency and clarity in scientific communication. For instance, 1 atm equals 760 torr, providing an easy conversion between these two units.