Question

please show all steps

3. Calculate the mass in grams, of KNO3(s) needed to make 750 mL of a 1.65 M solution.

Answer 1

Molar mass of KNO₃=Molar mass of K+Molar mass of N+3xMolar mass of O=39 g/mol+14 g/mol+3x16 g/mol

=39 g/mol+14 g/mol+48 g/mol

=101 g/mol

Molarity=number of moles/volume of solution (L)

=(Mass of KNO₃/Molar mass of KNO₃)/(Volume of solution(mL)/1000 mL/L) (1 L=1000 mL)

1.65 M=(Mass of KNO₃/101 g/mol)/(750 mL/1000 mL/L)

1.65 M x (750 mL/1000 mL/L)x101 g/mol=Mass of KNO₃

So mass of KNO₃ required=125 g