Gas Adsorption
In this experiment you will learn about gas adsorption to a solid surface.
Experimental Setup
A photograph of the setup that will be used in this experiment is shown in Figure 1.
There are two ways to set the system: as a fixed volume setup (Figure 2a), or as a variable volume setup (Figure 2b). The fixed volume setup will be used to measure the unknown volume of the system, as preparation for the adsorption experiment itself.
a)
b)
Components:
- Rotary vacuum pump
- "Trap"
- Valves 1 and 2: The valves separate the "trap" and the activated carbon tube, respectively, from the rest of the setup.
- Pirani gauge: Used to measure the pressure in the low to medium region.
- Piezo gauge: Used to measure the pressure in the medium to high region
The setup can be separated into three volumes as shown in Figure 3. V1 represents the entire system (pump, tubes, etc.). V2 and V3 are the sample volumes. The temperature of V1 and V2 is equal to the room temperature, and V3 is at liquid nitrogen temperature- 77K. V1 (or Vunknown) may be found by attaching the fixed volume to the setup. V2 and V3 can be found by comparing them to V1. The Experimental Procedure section describes the protocol in detail.
