The Ideal Gas Law is a fundamental equation in chemistry and physics that describes the behavior of ideal gases. It relates the pressure, volume, temperature, and number of moles of a gas.
Formula
The Ideal Gas Law is expressed by the equation:
\[ PV = nRT \]
Where:
- \( P \) = pressure of the gas (usually in atmospheres, Pa, or mmHg)
- \( V \) = volume of the gas (usually in liters or cubic meters)
- \( n \) = number of moles of the gas
- \( R \) = ideal gas constant (approximately 0.0821 L·atm/(K·mol) or 8.314 J/(K·mol))
- \( T \) = absolute temperature of the gas (measured in Kelvin)
Relationships
-
Pressure and Volume: At a constant temperature (isothermal condition), if the volume of the gas decreases, the pressure increases, and vice versa (Boyle's Law).
\[ P_1 V_1 = P_2 V_2 \]
-
Volume and Temperature: At a constant pressure (isobaric condition), if the temperature of the gas increases, the volume increases, and vice versa (Charles's Law).
\[ \frac{V_1}{T_1} = \frac{V_2}{T_2} \]
-
Pressure and Temperature: At a constant volume (isochoric condition), if the temperature increases, the pressure increases, and vice versa (Gay-Lussac's Law).
\[ \frac{P_1}{T_1} = \frac{P_2}{T_2} \]
-
Moles and Volume: Under constant temperature and pressure, the number of moles of gas is directly proportional to the volume (Avogadro's Law).
\[ \frac{n_1}{V_1} = \frac{n_2}{V_2} \]
Notes
- The Ideal Gas Law assumes ideal behavior of gases; real gases deviate from this behavior at high pressures and low temperatures.
- The law applies generally well to many gases under standard conditions but may not accurately predict the behavior of gases in extreme conditions.
- Remember to convert all units appropriately when applying the Ideal Gas Law. For example, convert degrees Celsius to Kelvin by adding 273.15.