Two sealed vials each contain 10.0 g of a pure gas
CHEMISTRY · Single correct · A Level · Chemistry · Amount of substance · Amount of substance
Problem
Two sealed vials each contain 10.0 g of a pure gas, one ammonia (NH3) and the other sulfur hexafluoride (SF6). Which statement correctly compares the number of gas molecules present in the two vials?
(a) Both vials contain the same number of molecules because their masses are equal, so the particle count must also be equal.
(b) The SF6 sample contains more molecules because each molecule has six fluorine atoms, giving more particles per molecule.
(c) The NH3 sample contains more molecules because its lower molar mass means that 10.0g corresponds to more moles.
(d) The SF6 sample contains more molecules because dividing 10.0g by its larger molar mass yields a greater number of moles.