A piston was expanded from 275.2 mL to 519.9 mL, after which it contained 0.07995 mol of gas. How many moles of gas were intially in the system?

Plz choose one of the compounds from the table and explain how you know the numbers of atoms in your formula. is it possible for two different compounds to be made from the exact same two elements? why or why not? with a limited number of elements (less than 120 are known), does this mean we also have a small number of compounds or do we have a large number of compounds in this world?

The empirical formula of a compound is ch2o and its mass is 120 amu/molecule, what is its formula?

The velocity of any object depends upon a) the location of the object. b) the location of the observer. c) which measurement tools are used. d) the relative motion of the observer.