Investigate the range of complexes formed by transition elements

[dagg3r]

We mixed 3 ml of 1M copper solfate solution and 3ml of sodium chloride solution.

This main copper ions are presented as Cu(h20)6 2+

We heated the test tube to produce cucl42- ions.

This is part a)

We placed 1M of copper2 sulfate solution in anoter test about 2 cm depth and slowly added 1 M sodium hydroxide solution and a thick precipitate formed.

We added 2M ammonia solution to this mixture and cy(Nh3)4 2+ ions are formed.

This is part b)

Is it possible to use stoichiometry to calculate the respective concentration, num of moles of them all

Ie


Initaially

Reaction

Equilibrium.

 

[chem_tr]

Yes, it is possible, for all reactions, that you may calculate the stoichiometry of almost all reactions, providing that you know molarity and volume of reactants.

Aqueous copper sulfate exists as [Cu(H₂O)₆]SO₄. You know molarity and volume, so just multiply them with each other to obtain the mole amount. You'll get 3 mmol.

[Cu(H₂O)₆]SO₄ + 4 NaCl ---> Na₂[CuCl₄] + Na₂SO₄ + 6 H₂O

This reaction is only possible in the presence of high chloride concentrations; water is a stronger ligand and it is not very easy to remove complexed water from the complex.

You formed a copper hydroxide precipitate (light blue) by adding sodium hydroxide; and then added ammonia to convert this into tetraminecopper hydroxide:

CuSO₄ + 2NaOH --> Cu(OH)₂ + Na₂SO₄

Cu(OH)₂ + 4NH₃ --> [Cu(NH₃)₄](OH)₂

You'll need to know the final volume of the reaction medium; then you can calculate the concentrations as inorganic reactions have yields as much as about 95-100%

Regards, chem_tr

 

[ravenprp]

The transition elements are known for their ability to form a wide range of complexes with different ligands. These ligands can be simple molecules such as water or more complex molecules such as ammonia. In this experiment, we mixed 3 ml of 1M copper sulfate solution with 3 ml of sodium chloride solution. The main copper ions present in this solution are Cu(H2O)6 2+, which is a complex formed with six water molecules as ligands.

Next, we heated the test tube to produce CuCl42- ions, which is a complex formed with four chloride ions as ligands. This complex is formed due to the displacement of water molecules by chloride ions in the solution.

In the second part of the experiment, we added 1M sodium hydroxide solution to 1M copper sulfate solution. This resulted in the formation of a thick precipitate, which is likely copper hydroxide (Cu(OH)2). This reaction can be represented as follows:

CuSO4 + 2NaOH → Cu(OH)2 + Na2SO4

The formation of copper hydroxide can be explained by the displacement of sulfate ions by hydroxide ions.

Further, we added 2M ammonia solution to this mixture, which resulted in the formation of cy(NH3)4 2+ ions. This complex is formed due to the coordination of four ammonia molecules as ligands with the central copper ion.

To answer the question of whether we can use stoichiometry to calculate the respective concentrations and number of moles of all the species involved, the answer is yes. Stoichiometry is a branch of chemistry that deals with the quantitative relationships between reactants and products in a chemical reaction. By using the balanced chemical equations for the reactions involved in this experiment, we can calculate the respective concentrations and number of moles of all the species present at equilibrium. However, it is important to note that the concentrations of the species may change as the reaction proceeds towards equilibrium. Thus, it is essential to take into account the equilibrium constant of the reaction, which is a measure of the extent to which the reactants are converted into products at equilibrium.