Understanding Equal Number of Molecules
To determine when three flasks containing CH4, CO2, and Cl2 gases will have equal numbers of molecules, we must consider the Ideal Gas Law and the concept of molar volume.
Ideal Gas Law
- The Ideal Gas Law states that PV = nRT, where:
- P = Pressure
- V = Volume
- n = Number of moles
- R = Ideal gas constant
- T = Temperature
Molar Volume
- At standard temperature and pressure (STP), one mole of any ideal gas occupies approximately 22.4 liters.
- Therefore, the number of molecules in a gas is directly proportional to the number of moles.
Equal Conditions for Gases
For the three gases to contain equal numbers of molecules, the following conditions must be met:
- Same Volume: Each flask must contain the same volume of gas.
- Same Temperature and Pressure: All flasks must be at the same temperature and pressure to ensure that the gases behave ideally.
Calculating Moles
- Given that the volume is the same and the conditions are identical, the number of moles of gas in each flask can be expressed as:
- n = PV/RT
- If P, V, R, and T are constant across all flasks, then the number of moles—and therefore the number of molecules—will be equal.
Conclusion
- To achieve equal numbers of molecules in the flasks containing CH4, CO2, and Cl2, ensure they are at the same volume, temperature, and pressure. This guarantees that the Ideal Gas Law applies uniformly across all three gases, leading to an equal number of molecules in each flask.

if temperature and pressure is same of all flask.