Answer:
it'll halve
Explanation:
the gas is compressed with twice the pressure. The volume will be halved.
im certain
Nitrogen is expressed with this formula:

which means that every nitrogen molecules is composed of two atoms.
Hope it helped,
Happy homework/ study/ exam!
Answer:
A. Gases;nonreactive
Explanation:
No ur not stupid, lol hope this helps!
What substance?.... I don't get it sorry.
Answer:
Comet
Explanation:
Comets are the astronomical bodies of variable sizes which are dominant in space and are often considered as the giant dirty snowball. It is comprised of a mixture of substances such as ice, dust, and gases such as carbon dioxide (CO₂), ammonia (NH₃) and methane (CH₄). These comets usually have an average size of about 750 meters to about 20 kilometers in terms of diameter. These comets can sometimes enter into the earth's atmosphere due to the gravitational pull of the earth and can cause massive destruction on earth like the mass extinction event or the meteoric impacts. When they move in the earth's atmosphere, it forms a long tail.