Answer:
c
Explanation:
when red litmus gets dropped into acid, it will turn blue, and when blue litmus gets dropped into acid, it turns red
A.
I believe it would be 2, if CaCO3 is your molecule you will have two because of the number in front :)
18 L
boyles law
P1V1 = P2V2
V2 = P1V1/P2
V2 = (.9 * 4)/.2
V2 = 18