Answer:
0.371
Explanation:
number of moles = mass / Ar
= 23.8g / 32.1 + (16.0 × 2)
= 0.37129485179 = 0.371 (3 s.f).
hope it helps :)
The given compound is 
Each formula unit of
has 2 mol Potassium (K) atoms, 2 mol Chromium (Cr) atoms and 7 mol Oxygen (O) atoms.
Atomic weight of potassium is 39.0983 amu
Atomic weight of Chromium is 51.9961 amu
Atomic weight of Oxygen is 15.9994 amu.
Therefore the formula weight of 

= 294.1846 amu
The Kinetic Molecular Theory has 5 main tenets, and they basically explain that the gas molecules are in constant motion. It is random and it causes constant collisions between the particles and also with the container's walls.
So, the answer is B. Kinetic Molecular Theory.
White tern catches fish including crustaceans, flying fish, squid, and others. Prior of plunging into water, it hovers initially over the water surface and then either dives or dips in the surface, without getting entirely submerged into water, and catches its target.
The food or fish is captivated in its small, however, sharp black beak that is specific as it bent upwards and tapers to a sharp point. It also possesses a long slender body with tapering, long wings, all of which encourage its diving or dipping activity into the surface of the water.