Chemistry Regent Exam August 2022
21. Compared to a 1.0-L sample of CO2 (g) in a sealed, rigid container at STP, a 1.0-L sample of CH4(g) in a sealed, rigid container at STP has the same (1) density (2) molar mass (3) chemical properties
(4) number of molecules
Explanation: STP stands for standard temperature and pressure. Thus, both gases have the same temperature, pressure and volume (1L). According to PV=nRT, two gases with the same temperature, pressure and volume must have the same number of moles of gas. The same amount of moles of gas means the same number of molecules.