Dalton's Law of Partial Pressures states that the total pressure of a gas mixture is equal to the sum of the partial pressures of the individual gases in the mixture. The partial pressure of a gas is the pressure that gas would exert if it alone occupied the total volume. For example, in a mixture of O2, N2, and CO2 gases with pressures of 37 kPa, 41 kPa and 57 kPa respectively, the total pressure is equal to the sum of the partial pressures, which is 37 + 41 + 57 = 135 kPa. This law can be used to calculate the pressure of a gas collected by water displacement, where the total pressure equals the pressure of the collected gas plus the vapor pressure of

1. Dalton’s Law of Partial Pressures

4. Pressure is directly proportional to the number of molecules present regardless of the kind of gas molecule P 1 + P 2 = P total