Gay-Lussacs Law Definition (Chemistry)

Gay-Lussacs law is an ideal gas law which states that at constant volume, the pressure of an ideal gas is directly proportional to its absolute temperature  (in Kelvin). The formula for the law may be stated as: Pwhere PGay-Lussacs law is also known as the pressure law. French chemist Joseph Louis Gay-Lussac formulated it around 1808. Other ways of writing Gay-Lussacs law make it easy to solve for the pressure or temperature of a gas: PPTWhat Gay-Lussac's Law Means The importance of this gas law is that it shows that increasing the temperature of a gas causes its pressure to rise proportionally (assuming the volume doesnt change). Similarly, decreasing the temperature causes the pressure to fall proportionally. Gay-Lussac's Law Example If 10.0 L of oxygen exerts 97.0 kPa at 25 degrees Celsius, what temperature (in Celsius) is needed to change its pressure to standard pressure? To solve this, you first need to know (or look up) standard pressure. Its 101.325 kPa. Next, remember that gas laws apply to absolute temperature, which means Celsius (or Fahrenheit) must be converted to Kelvin. The formula to convert Celsius to Kelvin is: K degrees Celsius 273.15 K 25.0 273.15 K 298.15 Now you can plug the values into the formula to solve for the temperature: TTTAll thats left is to convert the temperature back to Celsius: C K - 273.15 C 311.44 - 273.15 C 38.29 degrees Celsius Using the correct number of significant figures, the temperature is 38.3 degrees Celsius. Gay-Lussac's Other Gas Laws Many scholars consider Gay-Lussac to be the first to formulate Amontons law of pressure-temperature. Amontons law states that the pressure of a certain mass and volume of a gas is directly proportional to its absolute temperature. In other words, if the temperature of a gas increases, so does the gass pressure, providing its mass and volume remain constant. Gay-Lussac is also credited for other gas laws, which are sometimes called Gay-Lussacs law.  For instance, Gay-Lussac stated that all gases have the same mean thermal expansivity at constant pressure and temperature. Basically, this law states that many gases behave predictably when heated. Gay-Lussac is sometimes credited as being the first to state Daltons law, which says that the total pressure of a gas is the sum of the partial pressures of individual gases.