What is the relative rate of diffusion of NO2 and CH4

Which sample at stp has the same number of atoms as 18 liters of ne at stp

Equal numbers of moles of he(g), ar(g), and ne(g) are placed in a glass vessel at room temperature. if the vessel has a pinhole-sized leak, which of the following will be true regarding the relative values of the partial pressures of the gases remaining in the vessel after some of the gas mixture has effused?

What does it mean for something to be dissolved in watera- it is submerged in water moleculesb-it is stirred in the water moleculesc- it is surrounded by water molecules d-it has water molecules added to it