Question

Identify the property of a gas that is measured in each of the following: a. \(350 \mathrm{~K}\) b. \(125 \mathrm{~mL}\) c. \(2.00 \mathrm{~g}\) of \(\mathrm{O}_{2}\) d. \(755 \mathrm{mmHg}\)

Short answer

a. Temperature; b. Volume; c. Mass; d. Pressure

Step-by-step solution

Title - Understand the Question

Identify the property of a gas measured in each given unit. Analyze each unit provided and match it to the respective property (temperature, volume, mass, or pressure).

Title - Analyze the First Unit

For part (a): The unit is Kelvin (K). Temperature is measured in Kelvins. Therefore, the property for part (a) is the temperature of the gas.

Title - Analyze the Second Unit

For part (b): The unit is milliliters (mL). Volume is measured in milliliters. Therefore, the property for part (b) is the volume of the gas.

Title - Analyze the Third Unit

For part (c): The unit is grams (g). Mass is measured in grams. Therefore, the property for part (c) is the mass of the gas.

Title - Analyze the Fourth Unit

For part (d): The unit is millimeters of mercury (mmHg). Pressure is measured in millimeters of mercury. Therefore, the property for part (d) is the pressure of the gas.

Key concepts

temperature measurement

Temperature is a fundamental property of a gas that indicates its thermal state. It is usually measured in Kelvin (K). This unit is a part of the International System of Units (SI). Kelvin starts from absolute zero, the theoretically lowest temperature where all molecular motion ceases. This makes it beneficial for scientific calculations.

To measure temperature, we use thermometers. Thermometers can be based on various principles:

• Liquid Expansion - e.g., mercury or alcohol thermometers
• Electrical Resistance - e.g., thermistors and resistance temperature detectors (RTDs)
• Thermal Radiation - e.g., infrared thermometers

In gas studies, temperature directly affects kinetic energy, causing changes in pressure and volume.

volume measurement

Volume measurement refers to the amount of three-dimensional space a gas occupies. It is often measured in milliliters (mL), liters (L), or cubic meters (m³). For gases, volume is elastic and varies depending on the container and external conditions like temperature and pressure.

Several instruments measure gas volume:

• Graduated cylinders – Commonly used for liquids but can measure gases under controlled conditions.
• Gas syringes - Used in laboratories to measure gas during reactions.
• Gas meters - Measure the amount of gas passing through a chamber.

Volume is linked to pressure and temperature through the Ideal Gas Law: \[ PV = nRT \] where P is pressure, V is volume, n is the amount of substance, R is the gas constant, and T is temperature.

mass measurement

Mass indicates the amount of matter in a gas and is measured in grams (g) or kilograms (kg). The mass of a gas is crucial in calculating its density and molecular weight, which are key in various scientific and industrial applications.

Common tools to measure mass include:

• Balances and scales - Provide precise readings for substance mass.
• Gas analyzers - Sometimes used in complex systems to measure gas mass based on flow and density.

Remember that the mass of a gas remains constant despite changes in volume and pressure, making it a consistent property for scientific studies.

pressure measurement

Pressure is the force a gas exerts on the walls of its container and is typically measured in millimeters of mercury (mmHg), atmospheres (atm), or pascals (Pa). Pressure is influenced by the amount of gas, its temperature, and the container’s volume.

Common tools for measuring pressure are:

• Barometers - Measure atmospheric pressure.
• Manometers - Measure pressure in a closed system.
• Pressure gauges - Used in various applications to measure the pressure of gas or liquid.

Pressure connects to volume and temperature through Boyles' Law and Charles' Law, but the Ideal Gas Law ties it all together: \[ PV = nRT \].