Dalton’s Law of Partial Pressures Dalton’s Law of Partial Pressures, named after its discoverer John Dalton, describes the behavior of gas mixtures. It states that the total pressure of the gas, Ptot, is the sum of the partial pressures of each gas. The partial pressure of a gas is the pressure it would exert if it were alone in the container. In this assignment you will become more familiar with Dalton’s law. 1.Start Virtual ChemLab, select Gas Properties,and then select Dalton’s Law of Partial Pressuresfrom the list of assignments. The lab will open in the Gases laboratory. You will see a gas experiment with eight gas cylinders on the right. Make certain that the switch on the lower right of the lab bench is set to Ideal Gases. Note that the Ideal Gases each have a different molecular weight. 2.Select one of the Ideal Gas cylinders (to the right of the apparatus) by clicking on its white label. Click the red arrow on the brass cylinder valve until the meter reads 400. Add this Ideal Gas to the balloon by clicking the green Open Valveswitch once to add gas and again to stop. Add an amount of your choice but do not fill the balloon too full since you will be adding two additional gases. Click Return Tank.