Question

Which rigid cylinder contains the same number of gas molecules at STP as a 2.0-liter rigid cylinder containing H2(g) at STP?
(1) 1.0-L cylinder of O2(g)
(2) 2.0-L cylinder of CH4(g)
(3) 1.5-L cylinder of NH3(g)
(4) 4.0-L cylinder of He(g)

Answer 1

When we say STP that means the system is at its standard temperature and pressure. Both systems is having the same condition hence temperature and pressure is constant. We then set the amount of gas in both cases to be equal. Hence from the ideal gas law, 
PV=nRT we can say that with everything constant, volume must also be constant. 

The answer is (2) 2 L of methane gas. 

Answer 2

2.0-L cylinder of CH₄ (g) contains the same number of gas molecules at STP as a 2.0-liter rigid cylinder containing H₂(g) at STP.

What is ideal gas equation?

It is a hypothetical approximation of the behavior of many gases under many condition, and expressed as PV = nRT.

As in the question it is given that rigid cylinder have the same temperature and pressure i.e. have a standard temperature and pressure. According to the Avogadro's Law, under the same temperature and pressure if equal amount of gas is taken then no. of moles of gases are same.

Ideal gas equation PV = nRT justifies the above statement.

So, from the given 2.0-L cylinder of CH₄ (g) contains the same number of gas molecules at STP.

Hence, option (2) is correct i.e. 2.0-L cylinder of CH₄ (g) contains the same number of gas molecules.

To learn more about ideal gas, visit below link:

https://brainly.com/question/25290815