PV = nRT
P = nRT/V
Calculate pressure
V = nRT/P
Calculate volume
T = PV/nR
Calculate temperature
n = PV/RT
Calculate moles
Disclaimer
Results assume ideal gas behavior and may deviate at high pressures or low temperatures where real gas effects become significant.
The Ideal Gas Law is a fundamental equation in chemistry and physics that describes the behavior of ideal gases. It combines several gas laws (Boyle's Law, Charles's Law, and Avogadro's Law) into a single equation: PV = nRT. This equation relates the pressure (P), volume (V), temperature (T), and amount of gas (n) through the universal gas constant (R).
An "ideal gas" is a theoretical gas composed of randomly moving point particles that interact only through elastic collisions. While no real gas behaves exactly as an ideal gas, many gases approximate ideal behavior under normal conditions of temperature and pressure, making this equation incredibly useful for practical calculations.
Pressure (P)
The force exerted by gas molecules colliding with the container walls. Measured in atmospheres (atm), pascals (Pa), kilopascals (kPa), or bar.
Volume (V)
The space occupied by the gas. Typically measured in liters (L), milliliters (mL), or cubic meters (m³).
Temperature (T)
Must be in absolute scale (Kelvin) for calculations. Convert from Celsius by adding 273.15. Note that temperature must be above absolute zero.
Amount (n)
The quantity of gas in moles. One mole contains Avogadro's number (6.022 × 10²³) of particles.
Standard Temperature and Pressure (STP) is a reference condition used in chemistry calculations. At STP (0°C or 273.15 K and 1 atm), one mole of an ideal gas occupies exactly 22.414 liters. This is known as the molar volume of an ideal gas at STP.
At STP (0°C, 1 atm):
- 1 mole of ideal gas = 22.414 L
- Temperature = 273.15 K = 0°C
- Pressure = 1 atm = 101.325 kPa
The Ideal Gas Law has numerous practical applications across various fields:
- Chemistry Labs:Calculating the amount of gas produced or consumed in chemical reactions, determining molecular weights of gases.
- Engineering:Designing gas storage tanks, pneumatic systems, and HVAC systems.
- Meteorology:Understanding atmospheric pressure changes and weather patterns.
- Scuba Diving:Calculating air consumption rates and decompression requirements.
- Medical:Respiratory therapy calculations and anesthesia delivery.