Determine the resulting nitrate ion concentration when 900 m

Determine the resulting nitrate ion concentration when 90.0 mL of 0.542 M potassiu nitrate and 165.5 mL of 1.570M calcium nitrate are combined.

Solution

moles = molarity x volume (L)

so

moles of KNO3 = 0.542 M x 0.09 L = 0.04878 mol

moles of Ca(NO3)2 = 1.57 M x 0.1655 L = 0.259835 mol

now

moles of NO3 from KNO3 = 0.04878 mol x 1 mol NO3 / 1 mol KNO3 = 0.04878 mol

moles of NO3 from Ca(NO3)2 = 0.259835 mol x 2 mol NO3 / 1 mol Ca(NO3)2 = 0.51967 mol

now

total moles of NO3- = 0.04878 mol + 0.51967 mol = 0.56845 mol

total volume = 90 ml + 165.5 ml = 255.5 ml

now

concentration = moles of NO3- / volume (L)

concentration = 0.56845 mol / 0.2555 L

concentration of NO3- = 2.22485 M