Answer:
Substances with high boiling points condense at the bottom and substances with lower boiling points condense on the way to the top. The crude oil is evaporated and its vapours condense at different temperatures in the fractionating column.
Explanation:
answer above
Mendleev arranged his periodic table in order of Atomic Mass...
Explanation: <em>The hypothesis is a prediction, but it involves more than a guess. Most of the time, the hypothesis begins with a question which is then explored through background research. It is only at this point that researchers begin to develop a testable hypothesis.</em>
(Unless you are creating an exploratory study, your hypothesis should always explain what you expect to happen)