Physical Science (Gases, Liquids)

– The difference between liquid and gas (please explain clearly and deeply)

– Explain the experiment:
There are people sit in a line on the left corner of the room, a person stay behind them and spray the perfume in his right direction (so not toward the people are sitting), why the people in front smell the perfume first but not the people near him (the people he stays behind to)? (in condition that other problems are limited)