Giving brainliest please answer asap

Which formula can be used to calculate the molar mass of hydrogen peroxide

As air becomes more dense, (select all that apply) o. air weighs less o. gas molecules are closer together o. air is colder o. air weighs more o. gas molecules are further apart o. air is hotter

If anyone would be able to me out with these three questions it would be these are from the chem 2202 course.