KI + Cu(NO3)2 = I2 + KNO3 + CuI

KI (potassium iodide) + Cu(NO_3)_2 (copper(II) nitrate) ⟶ I_2 (iodine) + KNO_3 (potassium nitrate) + CuI (cuprous iodide)

Balance the chemical equation algebraically: KI + Cu(NO_3)_2 ⟶ I_2 + KNO_3 + CuI Add stoichiometric coefficients, c_i, to the reactants and products: c_1 KI + c_2 Cu(NO_3)_2 ⟶ c_3 I_2 + c_4 KNO_3 + c_5 CuI Set the number of atoms in the reactants equal to the number of atoms in the products for I, K, Cu, N and O: I: | c_1 = 2 c_3 + c_5 K: | c_1 = c_4 Cu: | c_2 = c_5 N: | 2 c_2 = c_4 O: | 6 c_2 = 3 c_4 Since the coefficients are relative quantities and underdetermined, choose a coefficient to set arbitrarily. To keep the coefficients small, the arbitrary value is ordinarily one. For instance, set c_3 = 1 and solve the system of equations for the remaining coefficients: c_1 = 4 c_2 = 2 c_3 = 1 c_4 = 4 c_5 = 2 Substitute the coefficients into the chemical reaction to obtain the balanced equation: Answer: | | 4 KI + 2 Cu(NO_3)_2 ⟶ I_2 + 4 KNO_3 + 2 CuI