Explanation:
The given data is as follows.
P = 3 atm
=
= 
= 9 L =
(as 1 L = 0.001
),
= 15 L = 
Heat energy = 800 J
As relation between work, pressure and change in volume is as follows.
W = 
or, W = 
Therefore, putting the given values into the above formula as follows.
W = 
= 
= 1823.85 Nm
or, = 1823.85 J
As internal energy of the gas
is as follows.
= Q - W
= 800 J - 1823.85 J
= -1023.85 J
Thus, we can conclude that the internal energy change of the given gas is -1023.85 J.
3 elements are present in HCOOH - hydrogen, oxygen, and carbon.
The answer is (4) Ag(s)
Solid Silver has a Face Centered Cubic crystal structure.
The remaining choices are gases (H2 & Ar) and liquid (Br). Liquids and gases do not form crystal structures as their atoms are loose.
Atomic number is less than 11