Final answer:
The concentration of the solution containing 20g of Potassium Nitrate in 100 mL of water is 20 grams per 100 mL, given that all the potassium nitrate is dissolved in the water.
Step-by-step explanation:
The concentration of a solution containing Potassium Nitrate (20g in beaker) and 100 mL of water is calculated by expressing the mass of the solute (potassium nitrate) per volume of solvent (water). Since the given unit of concentration is grams per 100 mL, you simply divide the mass of the solute by the volume of the solvent.
In this case:
Mass of potassium nitrate (solute) = 20g
Volume of water (solvent) = 100 mL
The concentration of potassium nitrate in the solution is 20 grams per 100 mL, as the entire mass of potassium nitrate is dissolved in exactly 100 mL of water.