A Sample of helium measuring 6l was kept at a pressure of 1.5atm. If pressure is doubled what would be its new volume?

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?

Which statement is best described as a atom

Amixture with the same composition throughout is!