General information about the hydrolysis of copper (II) chloride
DEFINITION
Copper(II) chloride- an average salt formed by a weak base - copper (II) hydroxide (Cu (OH) 2) and a strong acid - hydrochloric (hydrochloric) (HCl). Formula - CuCl 2.
Represents crystals of yellow-brown (dark brown) color; in the form of crystalline hydrates - green. Molar mass - 134 g / mol.
Rice. 1. Copper (II) chloride. Appearance.
Hydrolysis of copper(II) chloride
Hydrolyzed at the cation. The nature of the medium is acidic. Theoretically, a second step is possible. The hydrolysis equation has the following form:
First stage:
CuCl 2 ↔ Cu 2+ + 2Cl - (salt dissociation);
Cu 2+ + HOH ↔ CuOH + + H + (cation hydrolysis);
Cu 2+ + 2Cl - + HOH ↔ CuOH + + 2Cl - + H + (ionic equation);
CuCl 2 + H 2 O ↔ Cu(OH)Cl + HCl (molecular equation).
Second step:
Cu(OH)Cl ↔ CuOH + + Cl - (salt dissociation);
CuOH + + HOH ↔ Cu(OH) 2 ↓ + H + (cation hydrolysis);
CuOH + + Cl - + HOH ↔ Cu(OH) 2 ↓ + Cl - + H + (ionic equation);
Cu(OH)Cl + H 2 O ↔ Cu(OH) 2 ↓ + HCl (molecular equation).
Examples of problem solving
EXAMPLE 1
EXAMPLE 2
| Exercise | Write down the electrolysis equation for copper (II) chloride solution. What mass of substance will be released on the cathode if 5 g of copper (II) chloride is subjected to electrolysis? |
| Solution | We write the dissociation equation for copper (II) chloride in an aqueous solution: CuCl 2 ↔ Cu 2+ + 2Cl -. We conditionally write the electrolysis scheme: (-) Cathode: Cu 2+ , H 2 O. (+) Anode: Cl -, H 2 O. Cu 2+ +2e → Cu o ; 2Cl - -2e → Cl 2. Then, the electrolysis equation for an aqueous solution of copper (II) chloride will look like this: CuCl 2 \u003d Cu + Cl 2. Calculate the amount of copper (II) chloride substance using the data specified in the problem condition (molar mass - 134 g / mol): υ (CuCl 2) \u003d m (CuCl 2) / M (CuCl 2) \u003d 5/134 \u003d 0.04 mol. According to the reaction equation υ (CuCl 2) \u003d υ (Cu) \u003d 0.04 mol. Then we calculate the mass of copper released at the cathode (molar mass - 64 g / mol): m (Cu) \u003d υ (Cu) × M (Cu) \u003d 0.04 × 64 \u003d 2.56 g. |
| Answer | The mass of copper released at the cathode is 2.56 g. |
The binary substance copper chloride (monochloride), the formula of which is CuCl, is a salt of hydrochloric acid. It is a powder, usually white or green in color, very poorly soluble in water. The greenish hue of monochloride crystals is due to the presence of impurities of a divalent substance called copper ii chloride.
For the first time this compound was obtained by the great chemist Robert Boyle. This event happened a long time ago, and to obtain the scientist used simple metallic copper and divalent. Then, in 1799, Joseph Proust isolated dichloride crystals from monochloride. This reaction was a process of gradual heating of the solution, as a result of which copper (II) chloride lost part of the chlorine, about half of its presence. The separation of the dichloride from the monochloride was carried out by conventional washing.
Copper monochloride is a white crystalline substance that changes the shape of the crystal lattice at a temperature of 408 °C. Since this compound both melts and boils with little or no decomposition, its chemical formula is sometimes written as Cu2Cl2. Monochloride, however, like other copper compounds, is toxic.
The compound copper chloride, whose formula is written as CuCl2, outwardly represents dark brown wedge-shaped single crystals. When interacting with even a very small amount of water, the crystals of the compound change color: from dark brown, it successively turns into greenish, and then blue. Interestingly, if quite a bit is added to such an aqueous solution, the crystals will return to one of the intermediate states - they will become greenish.
The melting point of the substance is 537 ° C, and at a temperature equal to 954 - 1032 ° C, it boils. The compound is soluble in substances such as water, alcohol, ammonia. Its density is 3.054 g/cm3. With constant dilution of the solution and maintaining the temperature at 25 ° C, the molar electrical conductivity of the substance is 265.9 cm2 / mol.
Copper chloride is obtained by the action of chlorine on copper, as well as by carrying out the interaction reaction (II) with Industrial production is based on the roasting of mixtures of copper sulfides with sodium chloride. In this case, during the reaction, a temperature of 550-600 ° C should be provided, as a result of which, in addition to the substance under consideration, the presence in the gaseous state of such components as HCl, sulfur gases and arsenic compounds is detected. Production is known where the production of copper chloride is carried out by initiating an exchange reaction between copper sulphate and BaCl2.
At a temperature of 993 °C, the substance decomposes into CuCl and Cl2, its solubility in aqueous solutions is characterized by:
When dissolved in an aqueous solution of 25-degree temperature, 77.4 grams of copper chloride is completely dissolved in 100 grams of water;
When the temperature of the solution reaches 100 ° C, already 120 grams of the substance dissolves in it. In both cases, it is assumed that the density of CuCl2 was the same.
Copper chloride is widely used as a chemical catalyst, a component of pyrotechnic mixtures, and in the production of various mineral dyes. As used as a flue gas analyzer, it facilitates the calculation of flue gas concentrations and carbon dioxide levels. Dichloride is also used as an oxygen carrier at various stages of chemical production, such a technology, for example, is common in the production of organic dyes.
Copper chloride salt, for all its insolubility, is capable of forming a number of crystalline hydrates. At the same time, a concentrated solution of a substance has the ability to add nitric oxide, which is also widely used in the manufacture of medicines and in the chemical industry.
Copper chloride 2
Chemical properties
The tool is a binary inorganic substance, belongs to the class salts And halides . It can be considered as a salt formed hydrochloric acid And copper .
Racemic formula of Copper Chloride: CuCl2.
The molecular weight of this compound is 134.5 grams per mole. The substance melts at 498 degrees Celsius. The agent forms crystalline hydrates of the type CuCl2 nH2O .
Used in medicine copper chloride dihydrate.
The product in solid form is yellow-brown crystals. Compound crystalline hydrates depends on the temperature at which crystallization occurs. The substance is highly soluble in ethyl alcohol, water, acetone And methanol .
Reactions of copper chloride
The substance interacts with alkali , thus, as a rule, an insoluble base and a soluble salt are formed. Copper chloride reacts with metals that are located to the left of the metal in the electrochemical series Cu . Also, the compound is characterized by reactions ion exchange with other salts, as a result, an insoluble substance is formed and gas is released.
On an industrial scale, the agent is obtained by the reaction copper oxide 2 with hydrochloric acid or by exchange reaction barium chloride With copper sulphate .
There is also a connection Copper chloride 1 , in which copper is monovalent. Monochloride this metal is a rather toxic compound.
pharmachologic effect
Metabolic.
Pharmacodynamics and pharmacokinetics
Copper is essential for the body. For example, it takes part in a number of chemical reactions occurring in the liver tissues. After entering the body, the substance is almost completely metabolized.
Indications for use
Copper chloride solution is part of the solutions used in parenteral nutrition and satisfies the body's need for trace elements .
Contraindications
Preparations containing a solution cannot be used if the patient has substances in the composition, children under 10 years of age. Caution should be observed in renal or hepatic insufficiency.
Side effects
The drug is usually well tolerated by patients. Rarely, nausea and pain at the injection site occur during infusion.
Copper chloride, instructions for use (Method and dosage)
The agent is administered intravenously.
If the drug is initially in the form of a powder, it is diluted in solutions glucose or .
The resulting solution must be used within a day.
The dosage regimen and treatment regimen depend on the drug and the disease.
Overdose
An overdose of the drug occurs rarely. Most often it is used under the supervision of honey. staff and in the hospital.
If the drug is administered too quickly, it may develop: vomiting, sweating, hyperemia skin covers. Reactions disappear after a decrease in the rate of administration of the drug.
Interaction
It is possible to mix the substance in one syringe or package only with r-mi glucose or amino acids , whose concentration does not exceed 50%.
During pregnancy and lactation
The drug can be prescribed to pregnant women.
There is insufficient data on the use of this component during lactation.
Preparations containing (Analogues)
Coincidence in the ATX code of the 4th level:Copper chloride is included in the form of a dihydrate in the composition of the concentrate for the preparation of solutions for infusions Addamel N.
Basic information:
| Protective, inhibiting fungal spores and pathogens from entering leading tissues |
| Corona yellow body (anhydrous) to blue-green crystals (dihydrate) |
Release:
copper chloride: behavior in the environment
| Index | Meaning | Explanation | ||
| Solubility in water at 20 o C (mg/l) | 757000 Q4 High||||
| Solubility in organic solvents at 20 o C (mg/l) | 680000 Q4 - Methanol -||||
| Melting point (o C) | - - -||||
| Boiling point (o C) | - - -||||
| Decomposition temperature (o C) | - - -||||
| Flash point (o C) | - - -||||
| Partition coefficient in octanol/water at pH 7, 20 o C | P: - - -||||
| Specific Gravity (g/ml) / Specific Gravity | 3.39Q3-||||
| Dissociation constant (pKa) at 25 o C | - - -||||
| Note: | ||||
| Vapor pressure at 25 o C (MPa) | 1.00 X 10 -10 Q1 Not volatile||||
| Henry's law constant at 25 o C (Pa * m 3 / mol) | - - -||||
| Henry's law constant at 20 o C (dimensionless) | 7.29 X 10 -21 Calculated Not volatile||||
| Decay period in soil (days) | DT50 (typical) - - -||||
| - | ||||
| Aqueous photolysis DT50 (days) at pH 7 | Meaning: - - -||||
| - | ||||
| Aqueous hydrolysis of DT50 (days) at 20 o C and pH 7 | Meaning: - - -||||
| - | ||||
| Water precipitation DT50 (days) | - - -||||
| Water phase only DT50 (days) | - - -||||
| GUS washout potential index | - - -||||
| Concentration growth index in groundwater SCI (µg/l) at an application rate of 1 kg/ha (l/ha) | Meaning: - - -||||
| - | ||||
| Potential for particle bound transport index | - - -||||
| Koc - organic carbon partition coefficient (ml/g) | - - -||||
| pH resistance: | ||||
| Note: | ||||
| Freundlich adsorption isotherm | kf:-- | -|||
| - | ||||
| Maximum UV absorbance (l/(mol*cm)) | - - -||||
copper chloride: ecotoxicity
| Index | Meaning | Source / Qualitative indicators / Other information | Explanation | |
| Bioconcentration factor | BCF:-- | -|||
| Bioaccumulative potential | - - -||||
| LD50 (mg/kg) | 140 V3 Rat Moderately||||
| Mammals - Short term food NOEL | (mg/kg): -- | -|||
| Poultry - Acute LD50 (mg/kg) | - - -||||
| Birds - Acute toxicity (CK50 / LD50) | - - -||||
| Fish - Acute 96 hour CK50 (mg/l) | 0.24 F4 Rainbow trout Moderately||||
| Fish - Chronic 21 day NOEC (mg/l) | - - -||||
| Aquatic Invertebrates - Acute 48 hour EC50 (mg/L) | - - -||||
| Aquatic Invertebrates - Chronic 21 day NOEC (mg/l) | - - -||||
| Aquatic crustaceans - Acute 96 hour CK50 (mg/l) | 0.134F3 mysida shrimp Moderately||||
| Bottom microorganisms - Acute 96 hour CK50 (mg/l) | 0.043 F4 Chironomus mosquito High||||
| NOEC , static, Water (mg/l) | - - -||||
| Bottom Microorganisms - Chronic 28 day NOEC , Sedimentary rock (mg/kg) | - - -||||
| Aquatic plants - Acute 7 day EC50 , biomass (mg/l) | - - -||||
| Algae - Acute 72 hour EC50 growth (mg/l) | 0.55 H1 Unknown species Moderate||||
| Algae - Chronic 96 hour NOEC , growth (mg/l) | - - -||||
| Bees - Acute 48 hour LD50 (mcg/individual) | - - -||||
| Earthworms - Acute 14-day CK50 (mg/kg) | - - -||||
| Soil Worms - Chronic 14-Day Maximum Inactive Concentration, Reproduction (mg/kg) | 15 A4 Earthworm, as Cu, 8 week Moderate||||
| Other Arthropods (1) | LR50 (g/ha): - - -||||
| Other Arthropods (2) | LR50 (g/ha): - - -||||
| Soil microorganisms | - - -||||
| Available data on the mesoworld (mesocosm) | NOEAEC mg/l: - - -||||
copper chloride: human health
Basic indicators:
| Index | Meaning | Source / Qualitative indicators / Other information | Explanation | |
| Mammals - Acute oral LD50 (mg/kg) | 140 V3 Rat Moderately||||
| Mammals - Dermal LD50 (mg/kg body weight) | - - -||||
| Mammals - Inhalation | ||||
COPPER AND ITS COMPOUNDS
LESSON IN THE 11th NATURAL SCIENCE CLASS
To increase the cognitive activity and independence of students, we use the lessons of the collective study of the material. At such lessons, each student (or a pair of students) receives a task, the completion of which he must report on in the same lesson, and his report is recorded by the rest of the class in notebooks and is an element of the content of the lesson's educational material. Each student contributes to the study of the topic by the class.
During the lesson, the mode of work of students changes from intraactive (a mode in which information flows are closed within the students, typical for independent work) to interactive (a mode in which information flows are two-way, i.e. information goes both from the student and to the student, information is exchanged). At the same time, the teacher acts as the organizer of the process, corrects and supplements the information provided by the students.
The lessons of collective study of the material consist of the following stages:
1st stage - installation, in which the teacher explains the goals and program of work in the lesson (up to 7 minutes);
Stage 2 - independent work of students according to the instructions (up to 15 minutes);
Stage 3 - exchange of information and summing up the lesson (takes all the remaining time).
The lesson "Copper and its compounds" is designed for classes with an in-depth study of chemistry (4 hours of chemistry per week), is held for two academic hours, the lesson updates students' knowledge on the following topics: "General properties of metals", "Attitude towards metals with concentrated sulfuric acid, nitric acid", "Qualitative reactions to aldehydes and polyhydric alcohols", "Oxidation of saturated monohydric alcohols with copper (II) oxide", "Complex compounds".
Before the lesson, students receive homework: to review the topics listed. The preliminary preparation of the teacher for the lesson consists in compiling instructional cards for students and preparing sets for laboratory experiments.
DURING THE CLASSES
Installation stage
The teacher puts in front of the students the purpose of the lesson: based on existing knowledge about the properties of substances, predict, confirm in practice, generalize information about copper and its compounds.
Students make up the electronic formula of the copper atom, find out what oxidation states copper can exhibit in compounds, what properties (redox, acid-base) copper compounds will have.
A table appears in the students' notebooks.
Properties of copper and its compounds
| Metal | Cu 2 O - basic oxide | CuO - basic oxide |
| Reducing agent | CuOH is an unstable base | Cu (OH) 2 - insoluble base |
| CuCl - insoluble salt | CuSO 4 - soluble salt | |
| Possess redox duality | Oxidizers |
Stage of independent work
To confirm and supplement the assumptions, students perform laboratory experiments according to the instructions and write down the equations of the reactions performed.
Instructions for independent work in pairs
1. Ignite the copper wire in a flame. Note how its color has changed. Place the hot calcined copper wire in ethyl alcohol. Note the change in its color. Repeat these manipulations 2-3 times. Check if the smell of ethanol has changed.
Write down two reaction equations corresponding to the transformations carried out. What properties of copper and its oxide are confirmed by these reactions?2. Add hydrochloric acid to copper(I) oxide.
What are you watching? Write down the reaction equations, given that copper (I) chloride is an insoluble compound. What properties of copper(I) are confirmed by these reactions?3. a) Place a zinc granule into the copper(II) sulfate solution. If no reaction occurs, heat the solution. b) Add 1 ml of sulfuric acid to copper (II) oxide and heat.
What are you watching? Write down the reaction equations. What properties of copper compounds are confirmed by these reactions?4. Place a universal indicator strip into the copper(II) sulfate solution.
Explain the result. Write down the ionic equation of hydrolysis for the first stage.
Add a solution of honey(II) sulfate to a solution of sodium carbonate.
What are you watching? Write the equation for the reaction of joint hydrolysis in molecular and ionic forms.5.
What are you watching?
Add ammonia solution to the resulting precipitate.
What changes have taken place? Write down the reaction equations. What properties of copper compounds are proved by the reactions carried out?6. Add a solution of potassium iodide to copper(II) sulfate.
What are you watching? Write an equation for the reaction. What property of copper(II) does this reaction prove?7. Place a small piece of copper wire into a test tube with 1 ml of concentrated nitric acid. Close the tube with a stopper.
What are you watching? (Take the test tube under draft.) Write down the reaction equation.
Pour hydrochloric acid into another test tube, place a small piece of copper wire in it.
What are you watching? Explain your observations. What properties of copper are confirmed by these reactions?8. Add an excess of sodium hydroxide to copper(II) sulfate.
What are you watching? Heat up the precipitate. What happened? Write down the reaction equations. What properties of copper compounds are confirmed by these reactions?9. Add an excess of sodium hydroxide to copper(II) sulfate.
What are you watching?
Add a solution of glycerin to the resulting precipitate.
What changes have taken place? Write down the reaction equations. What properties of copper compounds prove these reactions?10. Add an excess of sodium hydroxide to copper(II) sulfate.
What are you watching?
Pour the glucose solution to the resulting precipitate and heat.
What happened? Write the reaction equation using the general formula for aldehydes to denote glucoseWhat property of the copper compound does this reaction prove?
11. Add to copper(II) sulfate: a) ammonia solution; b) sodium phosphate solution.
What are you watching? Write down the reaction equations. What properties of copper compounds are proved by the reactions carried out?
Phase of communication and debriefing
The teacher asks a question concerning the properties of a particular substance. The students who performed the corresponding experiments report on the experiment and write down the reaction equations on the blackboard. Then the teacher and students complete the information about the chemical properties of the substance, which could not be confirmed by reactions in the conditions of the school laboratory.
The order of discussion of the chemical properties of copper compounds
1. How does copper react with acids, what other substances can copper react with?
The reactions of copper are written with:
Concentrated and dilute nitric acid:
Cu + 4HNO 3 (conc.) = Cu(NO 3) 2 + 2NO 2 + 2H 2 O,
3Cu + 8HNO 3 (diff.) = 3Cu(NO 3) 2 + 2NO + 4H 2 O;
Concentrated sulfuric acid:
Cu + 2H 2 SO 4 (conc.) = CuSO 4 + SO 2 + 2H 2 O;
Oxygen:
2Cu + O 2 \u003d 2CuO;
Cu + Cl 2 \u003d CuCl 2;
Hydrochloric acid in the presence of oxygen:
2Cu + 4HCl + O 2 = 2CuCl 2 + 2H 2 O;
Iron(III) chloride:
2FeCl 3 + Cu \u003d CuCl 2 + 2FeCl 2.
2. What are the properties of copper(I) oxide and chloride?
Attention is drawn to the main properties, the ability to complex formation, redox duality. The equations of reactions of copper (I) oxide with:
Hydrochloric acid to form CuCl:
Cu 2 O + 2HCl = 2CuCl + H 2 O;
Excess HCl:
CuCl + HCl = H;
Reactions of reduction and oxidation of Cu 2 O:
Cu 2 O + H 2 \u003d 2Cu + H 2 O,
2Cu 2 O + O 2 \u003d 4CuO;
Disproportionation when heated:
Cu 2 O \u003d Cu + CuO,
2CuCl \u003d Cu + CuCl 2.
3. What are the properties of copper(II) oxide?
Attention is drawn to the basic and oxidizing properties. Equations for the reactions of copper(II) oxide with:
Acid:
CuO + 2H + = Cu 2+ + H 2 O;
Ethanol:
C 2 H 5 OH + CuO = CH 3 CHO + Cu + H 2 O;
Hydrogen:
CuO + H 2 \u003d Cu + H 2 O;
Aluminum:
3CuO + 2Al \u003d 3Cu + Al 2 O 3.
4. What are the properties of copper(II) hydroxide?
Attention is drawn to the oxidizing, basic properties, the ability to complex with organic and inorganic compounds. The reaction equations are written with:
Aldehyde:
RCHO + 2Cu(OH) 2 = RCOOH + Cu 2 O + 2H 2 O;
Acid:
Cu(OH) 2 + 2H + = Cu 2+ + 2H 2 O;
Ammonia:
Cu (OH) 2 + 4NH 3 \u003d (OH) 2;
Glycerin:
Decomposition reaction equation:
Cu (OH) 2 \u003d CuO + H 2 O.
5. What are the properties of copper(II) salts?
Attention is drawn to the reactions of ion exchange, hydrolysis, oxidizing properties, complexation. The equations for the reactions of copper sulfate are written with:
Sodium hydroxide:
Cu 2+ + 2OH - \u003d Cu (OH) 2;
Sodium Phosphate:
3Cu 2+ + 2= Cu 3 (PO 4) 2;
Cu 2+ + Zn \u003d Cu + Zn 2+;
Potassium iodide:
2CuSO 4 + 4KI = 2CuI + I 2 + 2K 2 SO 4 ;
Ammonia:
Cu 2+ + 4NH 3 \u003d 2+;
and reaction equations:
Hydrolysis:
Cu 2+ + HOH = CuOH + + H + ;
Co-hydrolysis with sodium carbonate to form malachite:
2Cu 2+ + 2 + H 2 O \u003d (CuOH) 2 CO 3 + CO 2.
In addition, you can tell students about the interaction of copper(II) oxide and hydroxide with alkalis, which proves their amphotericity:
Cu (OH) 2 + 2NaOH (conc.) \u003d Na 2,
Cu + Cl 2 \u003d CuCl 2,
Cu + HgCl 2 \u003d CuCl 2 + Hg,
2Cu + 4HCl + O 2 = 2CuCl 2 + 2H 2 O,
CuO + 2HCl \u003d CuCl 2 + H 2 O,
Cu(OH) 2 + 2HCl = CuCl 2 + 2H 2 O,
CuBr 2 + Cl 2 \u003d CuCl 2 + Br 2,
(CuOH) 2 CO 3 + 4HCl \u003d 2CuCl 2 + 3H 2 O + CO 2,
2CuCl + Cl 2 \u003d 2CuCl 2,
2CuCl \u003d CuCl 2 + Cu,
CuSO 4 + BaCl 2 \u003d CuCl 2 + BaSO 4.)
Exercise 3 Make chains of transformations corresponding to the following schemes and carry them out:
Task 1.
An alloy of copper and aluminum was treated first with an excess of alkali and then with an excess of dilute nitric acid. Calculate the mass fractions of metals in the alloy, if it is known that the volumes of gases released in both reactions (under the same conditions) are equal to each other
.
(Answer . Mass fraction of copper - 84%.)
Task 2. On calcination of 6.05 g of hydrated copper(II) nitrate, 2 g of residue was obtained. Determine the formula of the original salt.
(Answer. Cu(NO 3) 2 3H 2 O.)
Task 3. A copper plate weighing 13.2 g was lowered into 300 g of an iron (III) nitrate solution with a mass fraction of salt of 0.112. When it was taken out, it turned out that the mass fraction of iron(III) nitrate became equal to the mass fraction of the formed copper(II) salt. Determine the mass of the plate after it has been removed from the solution.
(Answer. 10 y.)
Homework. Learn the material written in the notebook. Compose a chain of transformations for copper compounds, containing at least ten reactions, and carry it out.
LITERATURE
1. Puzakov S.A., Popkov V.A. A manual on chemistry for university students. Programs. Questions, exercises, tasks. Samples of exam papers. Moscow: Higher school, 1999, 575 p.
2. Kuzmenko N.E., Eremin V.V. 2000 tasks and exercises in chemistry. For schoolchildren and entrants. M.: 1st Federal Book Trade Company, 1998, 512 p.
