B.
This method of expressing concentration is employed with solutions where both the solute and solvent are liquid. This is because it is easy to measure the volume of a liquid compared to that of a solid. Usually weight/weight is used in concentrations involving only solids.
You would use it in both atoms and molecules if it’s in are large quantity
It would be 23.46, since the next number is a 5 so we can round up.
Significant figures are:
ANY number that is not 0
Any 0 between two nonzero digits
Any 0 following a decimal (i.e 1.50)
D. the can from the car because there are fewer solute-solvent collisions.