11. Nitrogen dioxide (a brown gas) is prepared in a glass cylinder Althe onset
by dripping concentrated nitric acid onto a piece of copper at the
bottom of the glass cylinder. A second glass cylinder is placed
on top of the first one. The appearance of the apparatus at the
beginning and after a while is shown in the figures on the right.
11.1 Which gas is initially in the top cylinder?
11.2 What is in the top glass cylinder after a while?
11.3 What caused the brown colour to spread throughout the apparatus?
11.4 What happened to the air that was in the glass cylinders?
11.5 What does this experiment illustrate about the nature of matter?