Question

Identify the property of a gas that is measured in each of the following: a. \(425 \mathrm{~K}\) b. \(1.0 \mathrm{~atm}\) c. \(10.0 \mathrm{~L}\) d. \(0.50\) mole of He

Short answer

a. Temperature, b. Pressure, c. Volume, d. Amount of substance

Step-by-step solution

Determine the property measured by 425 K

The unit 'K' stands for Kelvin, which is used to measure temperature. Therefore, 425 K refers to the temperature of the gas.

Determine the property measured by 1.0 atm

The unit 'atm' stands for atmosphere and is used to measure pressure. Hence, 1.0 atm refers to the pressure of the gas.

Determine the property measured by 10.0 L

The unit 'L' stands for liters, which is used to measure volume. Therefore, 10.0 L refers to the volume of the gas.

Determine the property measured by 0.50 mole of He

The term 'mole' (abbreviated as mol) is used to measure the amount of substance. Hence, 0.50 mole of He refers to the amount of helium gas.

Key concepts

Temperature Measurement

Temperature is a critical property of gases that indicates how hot or cold a gas is. In scientific measurements, temperature is often measured in Kelvin (K). The Kelvin scale starts at absolute zero, which is the lowest possible temperature where molecular motion comes to a complete stop. Unlike Celsius or Fahrenheit, Kelvin does not have negative values, making it ideal for scientific calculations. For example, when we say 425 K, it means the gas has a temperature of 425 Kelvins, which is quite high. Understanding temperature helps in studying the energy and motion of gas molecules. It is closely linked to the pressure and volume of gases as described by the gas laws.

Pressure Measurement

Pressure is another essential property of gases. It is the force that the gas exerts on the walls of its container per unit area. The unit 'atm' stands for atmosphere and is a common unit for measuring pressure. One atmosphere is equivalent to the standard atmospheric pressure at sea level. When we say 1.0 atm, it means the gas exerts a pressure equal to the average atmospheric pressure at sea level. Pressure plays a crucial role in understanding how gases behave under different conditions. Boyle's Law, for instance, states that the pressure of a gas is inversely proportional to its volume when temperature is held constant. So, when we know the pressure, we can predict how a gas will respond to changes in volume or temperature.

Volume Measurement

Volume refers to the amount of space a gas occupies. It is typically measured in liters (L) which is a metric unit of volume. When we say 10.0 L, we mean that the gas occupies a volume of 10 liters. The volume of a gas is highly flexible and can change dramatically under different conditions of temperature and pressure. This flexibility is described by Charles's Law, which states that the volume of a gas is directly proportional to its temperature when pressure is held constant. Understanding the volume is crucial for applications ranging from breathing in human physiology to industrial processes requiring precise gas measurements. The volume helps determine the capacity of gas containers and systems.

Amount of Substance

The amount of substance in a gas is measured in moles (mol). A mole represents a specific quantity of molecules or atoms, making it a fundamental unit in chemistry. For example, 0.50 mole of helium (He) indicates that we have half a mole of helium atoms. This measurement is crucial for chemical reactions and equations where knowing the exact quantity of reactants and products is necessary. Avogadro’s Law states that equal volumes of gases, at the same temperature and pressure, contain the same number of molecules. Therefore, understanding the amount of substance allows for precise calculations and predictions about how gases will react and interact with each other. The concept of moles also helps in converting between mass and volume for gases.