How many moles of kno3 are required to make 0.50 liters of a 2.0 m solution of kno3?

Molarity is defined as the number of moles of solute dissolved in 1 L of solution.

KNO₃ - 2.0 M this means that 2.0 moles of KNO₃ are in 1 L of solution.

If 1 L contains - 2.0 moles

then 0.50 L contains - 2 mol/L x 0.50 L = 1 mol

Therefore 1 mol of KNO₃ is in 0.50 L solution.