Constant-volume gas thermometer
Definition
A constant-volume gas thermometer measures temperature by observing the pressure of a gas held at constant volume. The relationship between pressure and temperature is governed by the ideal gas law.
5 Must Know Facts For Your Next Test
- The constant-volume gas thermometer operates on the principle that the pressure of a gas is directly proportional to its temperature when the volume is kept constant.
- It provides highly accurate temperature measurements and is often used as a standard for calibrating other thermometers.
- The thermometer typically uses an inert gas like helium or nitrogen to minimize chemical reactions that could affect readings.
- The ideal gas law, $PV = nRT$, where $P$ is pressure, $V$ is volume, $n$ is the number of moles of gas, $R$ is the universal gas constant, and $T$ is temperature in Kelvin, underpins its operation.
- To measure temperature changes accurately, it’s crucial that the volume remains constant throughout the process.
Review Questions
- What principle does a constant-volume gas thermometer operate on?
- Why are inert gases like helium or nitrogen typically used in constant-volume gas thermometers?
- How does the ideal gas law relate to the operation of a constant-volume gas thermometer?
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Related terms
Ideal Gas Law: An equation of state for a hypothetical ideal gas. It states that $PV = nRT$, where $P$ represents pressure, $V$ represents volume, $n$ represents moles of gas, $R$ represents the universal gas constant, and $T$ represents temperature in Kelvin.
Kelvin Scale: A thermodynamic temperature scale where absolute zero (0 K) is defined as the point at which all thermal motion ceases. It is used as the standard unit for measuring thermodynamic temperature.
Thermal Equilibrium: A condition in which two systems in thermal contact with each other cease to exchange energy by heat. At thermal equilibrium, both systems have reached the same temperature.
