Answer:
There are multiple ways to check mass but I'll tell you one. Look below
Explanation:
One easy way of checking atomic mass is by adding protons and neutrons.
For example:
We have 5 protons and 4 neutrons.
5+4=9
I hope this helps (:
It would be F only because I wouldn’t make sense CI doesn’t exhibit crystalline neither does BR so F
Answer : The original volume of gas was, 3.0 L
Explanation :
Charles' Law : It is defined as the volume is directly proportional to the temperature of the gas at constant pressure and number of moles.

or,

where,
are the initial volume and temperature of the gas.
are the final volume and temperature of the gas.
We are given:

Now put all the given values in above equation, we get:

Thus, the original volume of gas was, 3.0 L