Which unit can be used to express the concentration of a solution?

(1) L/s (3) ppm

(2) J/g (4) kPa

(3) ppm or parts per million and it is used to express the concentration of very dilute solutions

ppm = grams of solute/grams of solution x 10^6

Also to clarify further, L/s is a unit of flow rate, J/g is a unit of energy per unit mass, and kPa is a unit of pressure known as kilo pascals which is equivalent to 1000 pascals