Answer:
Air & Water
Explanation:
Air and water is the common mixtures in the book of the book called "Science & Land"
The molecule with same molecular formula but different arrangement of atoms is said to be an isomer.
When 2,2-dimethylbutane reacts with chlorine in the presence of light gives three isomers that is 
(3-chloro-2,2-dimethylbutane), 
(1-chloro-2,2-dimethylbutane) and 
(1-chloro-3,3-dimethylbutane).
In above case, the molecular formula of all isomers are same i.e.
but chlorine is arranged in different positions of carbon. Thus, results isomers.
The reaction is shown in the image.
Answer:
their weight should be equal.
WAIT a pound of bricks is heavier?
Explanation:
A. Oxygen and nitrogen. ( Just think NO nitrogen oxygen )
It means is where something is removed or erased completely or something unwanted or unpleasant.
Hope this helps and the right meaning of expunge.
