MOДУЛЬ 3-5 РУССКИЙ

 

Module III. Solutions.

1.       Formulate the concept of "solution". Types of dispersed systems. The hydration theory of D.I. Mendeleev.

2.       Solubility. Solubility product.

3.       Methods for expressing the concentration of solutions: mass fraction of a substance in a solution, molar concentration, molar concentration equivalent (normal), molar concentration, titer.

4.       Raoult's first and second laws. Ebullioscopic and cryoscopic methods for determining the molar masses of substances.

5.       The theory of electrolytic dissociation. Electrolytes and non-electrolytes.

6.       How does the dissociation of ionic and covalent compounds occur?

7.       What is the degree of electrolytic dissociation? What does it depend on?

8.       What substances are strong, weak electrolytes?

9.       What is the dissociation constant? What factors does it depend on?

10.   When do ionic reactions go to the end?

11.   What value characterizes the ability of a poorly soluble electrolyte to dissolve?

12.   What solutions are called neutral? Sour? Alkaline?

13.   What is the pH of the medium?

14.   Salt hydrolysis. What salts can be hydrolyzed? What is the degree of hydrolysis? What factors does it depend on? What is the final (complete) hydrolysis?

 

       2. Solve the problems.

 

1.       Calculate the molar and equivalent concentration of a 20% calcium chloride solution with a density of 1.178 g / cm³.

2.       Calculate the equivalent concentration of a 20.8% HNO₃ solution with a density of 1.12 g / cm³. How many grams of acid is contained in 4 liters of this solution?

3.       Calculate the molar and equivalent concentration of a 16% solution of aluminum chloride with a density of 1.149 g / cm³.

4.       Calculate the normal and molar concentration of the solution with a mass fraction of aluminum sulfate of 20%. The density of the solution is 1.23 g/cm³.

5.       Calculate the titer and normal concentration of a solution with a mass fraction of H₂SO₄ 20% (pl. 1.15 g / cm³).

6.       50 g of sodium hydroxide was dissolved in 450 ml water. The density of the solution is 1.05 g / cm³. Calculate the mass fraction (in%) and the titer of the resulting solution.

7.       The density of a solution with a mass fraction of NaOH of 10% is 1.1 g / cm³. How many grams of sodium hydroxide will it take to prepare this 40 ml solution? What is its molar concentration?

8.       How many milliliters of 2M H₂SO₄ is required to prepare 500ml of 0.05M H₂SO₄? Calculate the titer and normal concentration of 0.05M H₂SO₄ solution.

9.       The density of a solution with a mass fraction of potassium hydroxide of 40% is 1.4 g / cm³. How many grams of KOH is required to prepare a 500 ml solution with a mass fraction of 40%? What is the normal concentration of this solution?

10.   How many grams of sodium sulfate should be taken to prepare a solution of Na₂SO₄ with a mass fraction of 8% (pl. 1.075 g / cm³) with a volume of 10 liters? Calculate the molar concentration of this solution.

11.   How many milliliters of sulfuric acid solution with a mass fraction of H₂SO₄ 96% (pl. 1.84 g / cm³) should be taken to prepare 250ml 0.5M H₂SO₄? What is the normal concentration of this solution?

12.   How much ammonium chloride is needed to prepare a 0.2M NH₄Cl solution with a volume of 500 ml? Calculate the normal concentration and titer of this solution.

13.   How many milliliters of sulfuric acid solution with a mass fraction of H₂SO₄ 30% (pl. 1.22 g / cm³) should be taken to prepare 0.1N. a solution of H₂SO₄ with a volume of 600 ml? Determine the molar concentration of this solution.

14.   14. 100 ml of solution contains 1 g of sodium chloride. Calculate the molar concentration and titer of this solution.

Calculate the molar concentration of 0.6N. Al (NO₃) ₃. Calculate the molar concentration of the solution containing 1 liter. 0.6 mol silver nitrate equivalents

      3. Solve the problems.

 

1.       A solution containing 11.04 g of glycerin in 800 g of water crystallizes at -0.279⁰C. Calculate the molar mass of glycerin.

2.       Calculate the percentage concentration of an aqueous solution of urea (NH₂)₂CO knowing that the crystallization temperature of this solution is -0.465⁰C. Cryoscopic constant water 1.86 ⁰.

3.       A solution containing 0.512 g of nonelectrolyte in 100 g of benzene crystallizes at 5.296⁰C. The crystallization temperature of benzene is 5.5⁰C. Cryoscopic constant 5.10. Calculate the molar mass of a solute.

4.       Calculate the crystallization temperature of a urea (NH₂)₂CO solution containing 5 g of urea in 150 g of water. Cryoscopic constant water 1.86⁰.

5.       A solution containing 3.04 g of C₁₀H₁₆O camphor in 100 g of benzene boils at 80.714⁰C. The boiling point of benzene is 80.2⁰C. Calculate the ebullioscopic constant of benzene.

6.       Calculate the molar mass of a non-electrolyte, knowing that a solution containing 2.25 g of this substance in 250 g of water crystallizes at -0.279⁰C. Cryoscopic water constant 1.86⁰.

7.       A solution containing 25.65 g of some non-electrolyte in 300 g of water crystallizes at -0.465⁰C. Calculate the molar mass of the solute. Cryoscopic water constant 1.86⁰.

8.       Calculate the cryoscopic constant of acetic acid, knowing that a solution containing 4.25 g of anthracene C₁₄H₁₀ in 100 g of acetic acid crystallizes at 15.718⁰C. Acetic acid crystallization temperature 16.65⁰C.

9.       The crystallization temperature of a solution containing 66.3 g of some non-electrolyte in 500 g of water is -0.558⁰C. Calculate the molar mass of the solute. Cryoscopic water constant 1.86⁰.

10.   What mass of aniline C₆H₅NH₂ should be dissolved in 50 g of ethyl ether so that the boiling point of the solution is 0.53⁰C higher than the boiling point of ethyl ether. Ebullioscopic Ethyl Ether Constant 2.12⁰.

11.   How many grams of urea (NH₂)₂CO should be dissolved in 75 g of water to lower the crystallization temperature by 0.465⁰C? Cryoscopic water constant 1.86⁰.

12.   How many grams of phenol C₆H₅OH should be dissolved in 125 g of benzene so that the crystallization temperature of the solution is below the crystallization temperature of benzene by 1.7⁰C? Cryoscopic constant of benzene 5.1⁰.

13.   How many grams of urea (NH₂)₂CO should be dissolved in 250 g of water to raise the boiling point by 0.26⁰C. Ebullioscopic water constant 0.52⁰.

14.   When 2.3 g of some non-electrolyte is dissolved in 125 g of water, the crystallization temperature decreases by 0.372⁰C. Calculate the molar mass of the solute. Cryoscopic water constant 1.86⁰.

15.   A solution of camphor weighing 0.552 g in 17 g of ether boils at a temperature of 0.461⁰C higher than pure ether. Ebullioscopic ether constant 2.16⁰. Determine the molecular weight of camphor.

 

4. Module IV. Redox reactions (RR). Fundamentals of Electrochemistry.

 

1.       What is called the oxidation state of an element?

2.       What is the oxidation state of elements in non-polar compounds? Give examples.

3.       Name the elements that always exhibit in compounds a positive oxidation state, a negative oxidation state.

4.       What reactions are called redox reactions? Give examples.

5.       What substances are called oxidizing agents? What are the typical oxidants.

6.       What substances are called reducing agents? What are the typical reducing agents.

7.       What types of RR do you know? Give examples of reactions for each type.

8.       What is called electrode potential?

9.       How is the standard electrode potential determined??

10.   What factors determine the electrode potentials?

11.   What is the stress range of metals? What characterizes the position of the metal in this row?

12.   Write the expression of the Nernst equation. What do the values ​​in this equation mean and in what units are expressed?

13.   How to find the molar mass equivalent of an oxidizing agent and a reducing agent?

14.   How the EMF of a galvanic cell is determined?

15.   Give a diagram of the Daniel-Jacobi element. Write the electronic equations of the processes occurring in this element.

16.   What is electrolysis? Where is it used?

17.   Formulate the laws of Faraday electrolysis. Write their expressions.

18.   What is current output? What is it usually expressed in?

19.   What is electrochemical equivalent? How is it measured?

 

   4. Solve the problems.

 

1. At what concentration of  Zn²⁺ ions the potential of the zinc electrode will be 0.015V less than its standard electrode potential?
2. A manganese electrode in a solution of its salt has a potential of -1.23V. Calculate the concentration of Mn²⁺ ions.
3. The potential of the silver electrode in the AgNO₃ solution was 95% of the value of its standard electrode potential. What is the concentration of Ag⁺ ions?
4. At what concentration of Cu²⁺ ions the value of the potential of the copper electrode becomes equal to the standard potential of the hydrogen electrode?
5. The standard electrode potential of nickel is greater than that of cobalt. Will this ratio change if we measure the potential of nickel in a solution of its ions with a concentration of 0.001 mol / l, and the potential of cobalt in a solution with a concentration of 0.1 mol / l?
6. The magnesium plate was dipped into a solution of its salt. In this case, the potential of magnesium turned out to be equal to -2.41V. Calculate the concentration of magnesium ions.
7. Calculate the redox potential of the system                                           

MnO₄^- + 8H⁺ + 5e^- = Mn²⁺ + 4H₂O, если C_MnO4^- =10^-5, C_Mn²⁺ = 10^-2, C_H⁺ = 0,2 mol / l.             (E˚_MnO4^-_/Mn⁺² = +1.510B).  

8. What is the concentration of  H⁺ ions in solution if the redox potential of the Cr₂O₇^2- + 14H⁺ + 6e^- = 2Cr³⁺ + 7H₂O  system is 1.61V, and the concentrations of  Cr₂O₇^-2  and  Cr³⁺  ions are 1 and 10^-6 mol / l, respectively?
9. Calculate the equilibrium potential of the electrode on which the reaction proceeds according to the equation PbO₂ + 4H⁺ + 2e^- = Pb2⁺ + 2H₂O. The standard potential is 1.45V. The concentration of the Pb2⁺ ion is 0.1; pH = 10, T = 298K.
10. Calculate the equilibrium potential of the electrode on which the reaction takes place
11. ClO₃^-+6H⁺+6e^- = Cl^- +3H₂O. The standard potential of the electrode is + 1.45V, the concentration of ClO₃^- and Cl^- ions is 0.1; pH = 5, T = 298K.
12. Determine the equilibrium potential of the electrode on which the reaction MnO₄^- + 8H⁺ + 5e^- = Mn²⁺ + 4H₂Oproceeds. The standard potential of the system is + 1.51V, the concentration of Mn²⁺ and MnO^4-  -1 ions, pH = 10, T = 298K.
13. Calculate the potential of the system MnO₄^- + 8H⁺ + 5e^- = Mn²⁺ + 4H₂O. E˚_MnO4^-_/Mn⁺² = +1.51B, concentrations of Mn²⁺ and Mn^O4-  -1 ions, pH = 5, Т = 298К.
14. Calculate the potential of the system ClO₃^-+6H⁺+6e^- = Cl^- +3H₂O. The standard potential is 1.45V, the concentration of ClO₃^- and Cl^-  ions is 1; pH = 10, T = 298K.
15. Determine the equilibrium potential of the electrode on which the reaction is taking place
16. Cr₂O₇^2- + 14H⁺ + 6e^- = 2Cr³⁺ + 7H₂O. Standard potential is + 1.33V, concentration of Cr³⁺  and Cr₂O₇^2- -1 ions; pH = 5, T = 298K.

 

      5. Solve the problems.

 

1. Make a diagram of a galvanic cell, in which the electrodes are magnesium and zinc plates, immersed in solutions of their ions with an active concentration of 1 mol / l. Calculate the EMF of the element.
2. Make a diagram, write the electronic equations of electrode processes and calculate the EMF of a galvanic cell consisting of lead and magnesium plates immersed in solutions of their salts with a concentration of  [Pb²⁺] = [Mg²⁺]= 0.01 mol / l.
3. Make a diagram, write the electronic equations of electrode processes and calculate the EMF of a galvanic cell consisting of plates of cadmium and magnesium immersed in solutions of their salts with a concentration of  [Mg²⁺] = [Cd²⁺] = 1 mol / l.
4. Make a diagram of a galvanic cell consisting of zinc and iron plates immersed in solutions of their salts. Write the electronic equations of the processes at the anode and cathode. What concentration should be taken of iron ions (mol / l) so that the EMF of the element becomes equal to zero, if  [Zn²⁺] = 1·10^-3mol / l.
5. Draw a diagram of a galvanic cell based on the reaction proceeding according to the equation      +Pb(NO₃)₂ = Ni(NO₃)₂ + Pb. Write the electronic equations of the processes at the anode and cathode. Calculate the EMF of an element if [Ni²⁺] = 0.01 mol / l, [Pb²⁺] = 0.0001 mol / l.
6. Draw diagrams of two galvanic cells, in one of which nickel is the cathode, and in the other the anode. Write for each of the elements the electronic equations of the processes at the cathode and anode. Calculate the EMF of each element.
7. Calculate the EMF of the element in which the equilibrium is established Zn + 2Ag⁺ = Zn²⁺ + 2Ag, [Zn²⁺] = 0.01 mol / l, [Ag⁺] = 10^-3 mol / l. Write the equations of electrode reactions.
8. Make diagrams of two galvanic cells, in one of which cadmium is the anode, in the other - the cathode. Write the equations of electrode processes and calculate the standard EMF of each element.
9. Make a diagram, write down the equations for the electrode processes of an element consisting of copper and cadmium plates immersed in a solution containing ions with [Cd²⁺] = [Cu²⁺] = 0.1 mol / l. Calculate the EMF of the element.
10. Make a diagram, write down the equations for the electrode processes of an element consisting of silver and lead plates dipped in a solution containing ions with [Ag⁺] = [Pb²⁺] = 1.0 mol / L. Calculate the EMF of this element.
11. Calculate the EMF of an element consisting of zinc and tin plates immersed in solutions of their salts with a concentration of [Zn²⁺] = 10^-4mol / l, [Sn²⁺] = 10^-2 mol / l. Write the equations of the electrode processes and make a diagram of the element.
12. Draw a diagram of an element consisting of copper and cadmium plates immersed in solutions with concentrations [Cd²⁺] = 10^-2 mol / l, [Cu²⁺] = 10^-3mol / l. Write the equations of electrode processes, calculate the EMF of the element.
13. Draw a diagram of an element consisting of iron and silver plates immersed in solutions with concentrations [Fe²⁺]= 10^-2 mol / l , [Ag⁺] = 10^-3 mol / l.Write the equations of electrode processes, calculate the EMF of the element.
14. Draw a diagram of an element consisting of zinc and copper plates immersed in solutions with concentrations [Zn²⁺] = 10^-2mol / l, [Cu²⁺] = 1mol / l. Write the equations of electrode processes, calculate the EMF of the element.

 

      6. Solve the problems.

 

1. What mass of copper will be released at the cathode during electrolysis of a CuSO₄ solution for 1 hour at a current of 4A?
2. Calculate the equivalent mass of the metal, knowing that during the electrolysis of a chloride solution of this metal, 3880 C of electricity were consumed and 11.742 g of metal will be released at the cathode.
3. What mass of potassium hydroxide was formed at the cathode during the electrolysis of the K₂SO₄ solution, if 11.2 liters of oxygen were released at the anode?
4. During the electrolysis of a salt of a certain metal for 1.5 hours at a current of 1.8 A, 1.75 g of this metal was released at the cathode. Calculate the equivalent mass of metal.
5. The electrolysis of a silver nitrate solution was carried out at a current strength of 2 A for 4 h. Make the electronic equations of the processes occurring on the electrodes. What is the mass of silver released at the cathode?
6. Electrolysis of a CuSO₄ solution was carried out with a copper anode for 4 h at a current strength of 50 A. At the same time, 224 g of copper were released. Calculate the current efficiency (%).
7. The electrolysis of a solution of a certain metal sulfate was carried out at a current of 6A for 45 min, as a result of which 5.49 g of metal was released at the cathode. Calculate the equivalent mass of metal.
8. Electrolysis of the CuSO₄ solution was carried out for 15 min at a current of 2.5 A. Allocated 0.72 g of copper. Calculate the current efficiency (%).
9. During the electrolysis of a salt of a trivalent metal at a current of 1.5 A for 30 min, 1.071 g of metal was released at the cathode. Calculate the atomic mass of a metal.
10. During the electrolysis of a cadmium salt solution, 3434Kl of electricity was consumed. 2g of cadmium was released. What is the equivalent mass of cadmium.
11. Determine the mass of zinc that will be released at the cathode during the electrolysis of a zinc sulfate solution for 1 hour at a current of 26.8A, if the current output of zinc is 50%.
12. When a current of 2A is passed for 1 h 14 min 24 s through an aqueous solution of metal (II) chloride, a metal with a mass of 2.94 g will be released on one of the graphite electrodes. What is the atomic mass of a metal if the current efficiency is 100% and what kind of metal it is?
13. 25Ah of electricity was passed through the cadmium sulfate solution. In this case, cadmium with a mass of 42.5 g was released at the cathode. Write the equations for the reactions occurring on the electrodes, calculate the current efficiency of cadmium.
14. A current of 13.4A was passed through the iron (II) sulfate solution for 1 hour. Determine the mass of iron that was released at the cathode if the current efficiency was equal to 70%. Write the equations for the reactions occurring on the electrodes.

 

5. Модуль V. Комплексные соединения.

 

1.       What is a complexing agent? Give examples.

2.       What is a ligand? What particles can be ligands?

3.       What is the coordination number of a complexing agent? What values ​​can it take?

4.       What complexes can there be (in terms of charge)? Give examples.

5.       What is the complex instability constant?

6.       What is called the coordination capacity of a ligand? Give examples of mono- and bidentate ligands.

7.       What complexes are called cyclic?

8.       What complexes are called multicore?

9.       What are complex compounds? Give examples.

10.   How the method of valence bonds explains the formation of bonds in complexes?

11.   What determines the spatial structure of the complex? Give examples.

12.   What determines the coordination number of a complexing agent?

13.   What particles are donors and acceptors in complex compounds? Give examples.

14.   What are the spatial structures of the complexes upon sp3-, sp3d2-hybridization of the atomic orbitals of the complexing agent? Give examples.

15.   As ligand field theory explains bond formation in complexes?

16.   How does the splitting of the d-orbitals of the complexing agent occur in the tetrahedral and octahedral fields of the ligands?

17.   On what basis are ligands divided into strong and weak?

18.   What is the spectrochemical range of ligands?

19.   What are high-spin and low-spin complexes?