Astudent mixes in a test tube 3.00ml of 0.050m cuso4with 7.00ml of 0.20m nh3/nh41 . the solution becomes a deep blue color. assuming all the cu2 is complexed with nh3to form the [cu(nh3)4]2 ion, determine the concentration of the complex in the solution.

Explanation:

We are given the volumes and concentrations of two reactants, so this is a limiting reactant problem.

We know that we will need moles, so, lets assemble all the data in one place.

                   Cu²⁺ + 4NH₃ ⟶ Cu(NH₃)₄²⁺

    V/mL:   3.00      7.00

c/mol·L⁻¹:  0.050   0.20

1. Identify the limiting reactant

(a) Calculate the moles of each reactant  

(b) Calculate the moles of Cu(NH₃)₄²⁺ that can be formed from each reactant

(i) From Cu²⁺

(ii) From NH₃

NH₃ is the limiting reactant, because it forms fewer moles of the complex ion.

(c) Concentration of the complex ion