How do I do these chemistry gas equations?

What is the volume of the fluid in the graduated cylinder with accuracy and measured to the correct degree of precision? 41.2 ml 42.0 ml 41.23 ml 41.89 ml

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

Agas has an empirical formula ch4. 0.16g of the gas occupies a volume of 240cm^3 what is the molecular formula of the me anyone who !