In one or two sentences, explain why the combined weight of several liquids mixed in an open flask can be less than but never more than the sum of all weights of the ingredients.
The combined weight of several liquids mixed in an open flask can be less than the sum of all weights of the ingredients because some of the liquids may be less dense and create a layer on top. However, the weight can never be more than the sum of all weights because no new matter is being added, only being rearranged.
