Answer:
[NO₃⁻ ] = 2.596 M
Explanation:
Ca(NO₃)₂ dissolves in water according to the following equation:
Ca(NO₃)₂ ⇒ Ca²⁺ + 2NO₃⁻
The moles of Ca(NO₃)₂ that dissolve is found as followed:
(21.3 g) / (164.10 g/mol) = 0.1298... mol
The number of NO₃⁻ ions are related to the above quantity by the molar ratio:
(0.1298 mol Ca(NO₃)₂) (2NO₃⁻/Ca(NO₃)₂) = 0.2596...mol NO₃⁻
The concentration of the nitrate ions is then calculated:
[NO₃⁻ ] = (0.2596...mol) / (100.0ml) x (1000mL/L) = 2.596 M
