The answer above is correct:)
Answer:

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

Answer:
5.46% is the percent by mass concentration of the solution.
Explanation:
Mass of LiBr= 8.2 g(Solute)
Mass of solution = 150 g (Solution)
Mass of solution = Mass of solute + Mass of solvent
Mass of solute < Mass of solvent (Always)
Mass of water = 150 g - 8.2 g = 141.8 g (solvent)
Mass percentage is given as:


5.46% is the percent by mass concentration of the solution.
Answer: B. High precision
Explanation: