What physical property and reaction type are used by extraction as useful techniques to separate and purify mixtures of compounds

Why are the trends and exceptions to the trends in ionization energy observed?

Mary is conducting an experiment on how pollution affects plant growth. how can she ensure that her data are reliable?

Alidded glass container is filled with a colored gas. after a period of time, it is observed that the gas is uniformly spread throughout the box and that the movement has slowed considerably. next, a warm iron plate is carefully placed under the box. why is there resumed movement of the gas in the container?