At STP,which sample contains twice the number of molecules found in 4.00 L of hydrogen gas?

Question

Quizplus · Accepted Answer

According to Avogadro's Law, equal volumes of gases at the same temperature and pressure contain the same number of molecules. Therefore, 4.00 L of H2 gas contains a certain number of molecules, and in order to have twice that number, we need to find a sample with twice the volume. The only option that fits this criteria is 8.00 L of He gas, since He gas has about half the molar mass of H2, meaning that it takes twice the volume to contain the same number of molecules as H2. Thus, 8.00 L of He gas contains twice the number of molecules as 4.00 L of H2 gas at STP.

At STP,which Sample Contains Twice the Number of Molecules Found