Question

I was studying real gases and found that H2 and He have Z>1, that means they cannot be compressed even at high pressure as their graph is always upwards meaning Z>1 always. Then how come the balloon seller have compressed helium in his cylinder?

Answer 1

H2 and He can be compressed, even though they have a Z factor greater than 1. The balloon seller is able to compress helium by cooling it down to very low temperatures, which increases its compressibility. Other factors such as temperature and pressure can also affect the compressibility of H2 and He.

Step-by-step explanation:

In the case of H2 and He, they have Z>1, which means they deviate from ideal gas behavior. The Z factor, also known as the compressibility factor, is a measure of how much a real gas deviates from ideal gas behavior. Z>1 indicates that the gas is less compressible than an ideal gas. However, this does not mean that H2 and He cannot be compressed at all.

The balloon seller can compress helium in cylinders by cooling it down to very low temperatures. At low temperatures, the compressibility of gases increases, and even gases like helium can be compressed to some extent. By reducing the temperature of helium, the balloon seller is able to increase its compressibility and store it in cylinders.

It is important to note that while H2 and He have Z>1 at normal conditions, other factors such as temperature and pressure can affect their compressibility and make it possible to store them in compressed form.