J.R. S. answered 04/17/20
Ph.D. University Professor with 10+ years Tutoring Experience
NaNO3 ==> Na+ + NO3-
0.893 L x 0.509 mol/L x 1 mol NO3/mole NaNO3 = 0.455 moles NO3-
Ca(NO3)2 ==> Ca2+ + 2NO3-
0.793 L x 0.695 mol/L x 2 mol NO3/mol CaNO3 = 1.10 moles NO3-
Total moles NO3- = 0.455 + 1.10 = 1.56 moles NO3-
Total volume in liters = 0.893 + 0.793 = 1.69 liters
[NO3-] = 1.56 moles/1.69 L = 0.923 M