School Science Lessons
2024-11-09
Copper, Cu
Contents
Copper properties: 12.1.0
Copper compounds: 12.2.0
Copper experiments: 12.3.0
Tests for copper: 12.4.0
Prepare copper compounds: 12.5.0
Reactions of copper: 12.6.0
12.1.0 Copper propertes
Copper, Cu (Latin cuprum copper), copper (I) ion Cu + , copper (II) ion Cu 2+, Aqueous copper ion, Cu 2+ is blue.
Copper, RSC
Copper, Table of the Elements
Copper, natural copper, (Geology)
Copper is an electrical and thermal conductor, corrosion resistant, diamagnetic, and an abundant free element.
Copper, element (cuprum), copper (I) Cu + , copper (II) Cu 2+ is red, lustrous, but brown-green if weathered.
Copper, essential element for human body for red blood cells and bone growth, folk medicine, (copper bracelet for arthritis?)
Copper sheeting, 900 mm width × 600 mm depth × 0.7 mm height, sheet
Copper, std (10.00 g Cu), ICP Solution, LR tablets, AAS Solution, precipitated
Copper, metal foil (0.13 mm), bronze powder (electrolytic), turnings, nails, filings, wire, sheet, malleable
Copper toxicity: 4.7
Copper wire, 18 SWG, bare, 1.22 mm diameter, 0.0418 Ohm / m
Copper wire connecting is PVC-covered
Copper is a metallic element used for coin alloys, electrical wiring, heating vessels, jewellery, roofing material, conducting electricity and lightning conductors.
Copper, Cu (cuprum) is a bright red-orange, ductile, malleable and ductile transition metal, with high electrical and thermal conductivity.
Copper deficiency may occur in infants fed only on cow's milk.
Copper bracelets may alleviate, but not cure, arthritis.
Copper bowls may be preferable for beating cream.
Copper poisoning may occur from water standing for a long time in copper pipes or copper hot water service.
It becomes dull when exposed to air, and in moist air becomes coated with verdis blue or green, basic copper carbonate.
It can be attacked by mineral acids, e.g. hydrochloric and sulfuric acids and organic acids, e.g. acetic acid.
It competes with zinc for entry from the intestines, so an increase in dietary zinc may result in copper deficiency.
It has reaction with dilute HCl or H2SO4 or with water.
It is a cofactor for many enzymes and proteins, and is used in the development of nerve, bone, blood and connective tissue.
It is an excellent conductor of heat.
It is extracted from cuprite Cu2S, and malachite (basic copper (II) carbonate, Cu2CO3(OH)2.
It is available as ingots, filings, foil, powder, turnings, nails, wire, turnings.
It is soluble in dilute ammonia.
It is incompatible with alkali solutions, sodium azide and acetylene.
It is the only red or red-brown metal.
It reacts with concentrated oxidizing acids, HNO3 or H2SO4 to produce high oxidation number ions, and sulfur dioxide SO2 or nitrogen dioxide, NO2.
It reacts with strong oxidants, e.g. chlorates, bromates and iodates, to cause an explosion hazard.
Most Cu + compounds are white, but copper (I) oxide is brick red.
The heated powder forms an oxide.
The recommended daily allowance, RDA, is 1.5 to 3.0 mg.
Atomic number: 29, Relative atomic mass: 63.546, RD. 8.92, MP = 1083 o C, BP = 2595 o C.
Specific heat capacity: 385 J kg -1 K -1 .
12.2.0 Copper compounds
Prepare copper compounds: 12.5.0
Azurite: 35.2.10, (Geology)
Bornite: 35.2.15 (Geology)
Brass
Bronze
Chalcocite: 35.2.21, (Geology)
Chalcopyrite: 35.2.22, (Geology)
Coins, (Copper coins), Chemistry
Contantan wire
Copper (I) oxide
Copper (I) sulfide, Cu2S, copper monosulfide, copper-glance mineral, chalcocite, grey to black, metallic lustre, (Geology)
Copper (I) sulfide, Cu2S, indigo copper. (in luminous paints, catalyst), Harmful if ingested
Copper (II) acetate, copper (II) ethanoate, copper acetate, cupric acetate, copper (II) acetate monohydrate, Cu(CO2CH3)2.H2O
Copper (II) acetate, prepare low cost: copper (II) carbonate with distilled white vinegar
Copper (II) carbonate
Copper (II) chloride
Copper coins, Chemistry
Copper ferrocyanide, semipermeable membrane: 9.1.2
Copper (II) acetoarsenite, (II) arsenate, arsenite, Toxic
Copper (II) hydroxide, Cu(OH)2, cupric hydroxide, blue pigment
Copper (II) nitrate
Copper (II) oxide
Copper (II) sulfate
Copper (II) sulfide, CuS, coins, electrical wiring, copper (II) sulfide 6, chalcocite, copper glance, redruthite, Harmful if ingested
Copper (II) sulfide, in electrical wiring, copper glance, redruthite, Harmful if ingested
Copper 5.1.11, brass and bronze alloys
Copper, natural copper: 35.2.25 (Geology)
Copper alloys, CZ copper-zinc brass, PB phosphor bronze, LG leaded gunmetal, CT copper-tin bronze
Copper deficiency in soils: 6.13.4
Copper ferrocyanide, Cu2Fe(CN)6, semipermeable membrane
Copper oxychloride, ClCu2H3O3: 4.6.4
Copper phosphide, copper (I) phosphide, insoluble in water, in phosphor bronze, fluorescent in UV light, Harmful if ingested
Copper plating (electroplating): 15.1.2
Copper pyrite, chalcopyrite: 35.2.22, (Geology)
Copper-aluminium alloys, bronze: 5.1.6
Copper-nickel alloys: 5.1.8
Copper-tin alloys, bronze: 5.1.9
Copper-zinc alloys, brass: 5.1.10
Covellite: 35.2.25, copper sulfide mineral, CuS, (Geology)
Malachite, copper (II) carbonate: 35.2.44, (Geology)
Tetraamminecopper (II) sulfate monohydrate, Cu(NH3)4SO4.H2O
12.3.0 Copper experiments
Bunsen burner flame can melt copper wire: 22.1.3
Burn copper in chlorine: 12.4.8.2
Concentrated acids with metals, sulfuric acid with copper: 12.3.10
Copper coil candle snuffer: 23.7.6 (Physics)
Copper cycle reactions: 11.1.3
Copper ions, movement of copper and chromate ions: 33.89
Copper ions, movement of copper ions in ammonium nitrate solution: 11.2.3
Copper ions, Movement of ions, between microscope slides: 33.90
Copper residues: 3.5.2 (disposal)
Cupaloy, Copper-chromium alloys: 5.5.14
Dilute nitric acid with copper: 12.3.11
13.3.8 Dilute nitric acid with copper
Effect of copper on the growth of algae: 9.3.1
Electrical energy from the displacement of copper by zinc: 3.84
Coin cells, Electricity from two coins: 33.4.51
Electroforming using copper: 15.1.7
Electroplating copper, copper flashing of iron: 15.1.10
Electroplating, Zinc plating of copper: 15.1.6
Etchants: 7.9.20.1 (3.)
Faraday's first law: 15.1.1
Group 2 tests for Bi 3+ , Cd 2+ , Cu 2+ , Sn 2+ : 12.11.4.2
Heat copper foil to form copper (II) oxide: 8.2.12
Heat copper with iodine crystals (synthesis reaction): 12.2.2.2
Magnesium displaces copper from solution of copper ions: 12.4.13
Heat copper wire with iodine crystals (synthesis reaction): 12.2.2.2
Heat copper with sulfur: 12.2.2.8
Movement of copper ions and chromate ions: 33.89
Movement of copper ions in ammonium nitrate solution: 11.2.3
Movement of ions, between microscope slides: 33.90
Nitric acid with copper, (Dilute nitric acid): 13.3.8
Nitric acid with copper. (Concentrated nitric acid): 13.3.9
Oxidation of acetone vapour, copper catalyst: 17.3.10
Oxidize copper foil or a copper coin : 12.7.9.0
Prepare copper from brass: 12.7.10
Prepare copper from copper oxide: 12.7.11.1
Prepare copper from copper sulfate: 12.7.11.5
Prepare copper compounds: 12.5.0
Prepare iron sulfate with copper (II) sulfate solution: 12.15.3.1
Prepare lead sulfate with copper (II) sulfate solution: 12.15.3.3
Prepare nitrogen dioxide, [nitrogen (IV) oxide, NO2]: 3.47.0
Prepare zinc sulfate with copper sulfate solution: 12.15.3.2
Prepare verdigris with copper and vinegar: 12.11.1
Prepare yellow invisible ink, with copper (II) sulfate: 12.15.1
Reactions of copper: 12.6.0
Recycle copper: 12.7.8
Strong electrolytes: 15.8.2
Sulfides, List of sulfides (copper (I) sulfide, copper (II) sulfide):1.24
12.18.5.8 Sulfuric acid dehydrates copper (II) sulfate crystals
Wood treated with copper chrome arsenate (CCA): 12.2.2.1
Zinc with copper in sulfuric acid: 12.14.2.5
Sulfuric acid, formerly used with nitre, KNO3, for separating silver from copper
Sulfuric acid dissolves most metals, but not copper.
Sulfuric acid dissolves metal oxides, including copper oxide.
12.4.0 Tests for copper
Tests for copper: 12.11.3.19
Tests for copper: 12.11.3.8 (See: 5.)
Tests for copper wire with a flame test: 12.7.11.0
Tests for oxidizing agents: 15.4.17
Tests for water with anhydrouscopper (II) sulfate: 8.2.1
12.5.0 Prepare copper compounds
Prepare copper from brass: 12.7.10
Prepare copper from copper oxide: 12.7.11.1
Prepare copper from copper sulfate: 12.7.11.5
Prepare copper (I) chloride: 12.7.7
Prepare copper (I) oxide: 12.7.6
Prepare copper (I) oxide with golden syrup: 12.7.11.7
Prepare copper (II) ammonium sulfate crystals: 12.7.4
Prepare copper (II) carbonate: 10.1.3
Prepare copper (II) carbonate and copper (II) oxide: 12.15.4
Prepare copper (II) sulfate crystals with copper oxide: 12.7.11.2
Prepare copper (II) sulfate algicide 12.7.11.3
Prepare copper (II) oxide, Heat copper foil to form copper (II) oxide: 12.15.5
Prepare cuprammonium sulfate: 12.7.5
Prepare iron sulfate with copper (II) sulfate solution: 12.15.3.1
Prepare lead sulfate with copper (II) sulfate solution: 12.15.3.3
Prepare rayon, basic copper carbonate with ammonia solution: 3.3.8
Prepare verdigris with copper and vinegar: 12.11.1
Prepare yellow invisible ink, with copper (II) sulfate: 12.15.1
Prepare zinc sulfate with copper sulfate solution: 12.15.3.2
Prepare sulfides: 12.18.2.0, (See: 1.)
12.6.0 Reactions of copper
Reactions of copper (I) compounds: 12.7.3
Reactions of copper (II) ions: 12.7.2
Reactions of copper (II) oxide, CuO: 12.7.1.0
Reactions of chlorine with copper: 12.4.14
Copper (I) oxide, Cu2O
Copper (I) oxide, Cu2O, copper oxide, cuprous oxide, brown copper oxide, red copper oxide, ruby copper, cuprite
It is used for craft, red solid, insoluble, deliquescent (used to make red glass).
Copper (I) oxide, cuprite, copper ore, "copper oxide", Harmful if ingested
Copper (I) oxide, Solution < 25%, Not hazardous
Alkalis with basic oxides, copper oxide: 12.7.6
Copper (I) oxide with hot dilute sulfuric acid: 12.2.6.5
Copper oxide with sodium hydrogen sulfate: 12.3.11
Heat copper foil to form copper (II) oxide: 8.2.12
Prepare copper (I) oxide, CuO: 12.7.6
Copper (II) carbonate, CuCO3
Azurite: 35.2.10, (Geology)
Prepare rayon, basic copper carbonate with ammonia solution: 3.3.8
Copper (II) carbonate, CuCO3, cupric carbonate, blue-green powder, Harmful if ingested, low cost
Copper (II) carbonate basic, CuCO3.Cu(OH)2, cupric carbonate basic, basiccopper carbonate (azurite, malachite),
cupric carbonate, green precipitate, Bremen blue, green verditer, craft green glaze, verdigris on copper exposed to atmosphere
Copper (II) chloride, CuCl2
Alkalis with salts, hydroxide ions: 12.7.8
Copper (II) chloride, cupric chloride, brown powder, Harmful, Environment danger
Copper (II) chloride, anhydrous copper chloride, cupric chloride, brown-yellow powder, Harmful if ingested
Copper (II) chloride, Solution < 25%, Not hazardous
Copper (II) chloride dihydrate, copper (II) chloride 2H2O, copper chloride, cupric chloride, Harmful
Copper (II) chloride, CuCl2, cupric chloride, brown-yellow powder, covalent, green fireworks, copper (II) chloride dihydrate, CuCl2.2H2O
Copper (II) nitrate, Cu(NO3)2
Copper (II) nitrate, Cu(NO3)2, Copper (II) nitrate, Cu(NO3)2.3H2O, copper (II) nitrate 3H2O, cupric nitrate, Harmful
Copper (II) nitrate, copper nitrate crystals, blue solid, deliquescent, anhydrous form probably covalent
Copper (II) nitrate hydrate, copper nitrate hydrated, cupric nitrate Std, blue crystal, deliquescent, Harmful
Copper (II) nitrate, For 0.1 M solution, 29.6 g in 1 L water
Copper (II) nitrate pentahydrate, Cu(NO3)2.5H2O
Prepare Cu(NO3)2: copper (II) carbonate with nitric acid
Copper (II) oxide, CuO
Copper (II) oxide, black copper oxide, cupric oxide, melconite, tenorite, black solid, soluble in dilute acids
Copper (II) oxide, used in craft, deep blue colour in glass
Copper (II) oxide (copper oxide), basic oxide (metal oxide): 12.13.9
Copper (II) oxide, "copper oxide", cupric oxide, Harmful if ingested
Dilute acids with basic oxides, (metal oxides), copper (II) oxide : 12.4.3
Heat food with copper (II) oxide: 9.1.8
Heat zinc with copper (II) oxide: 12.13.11
Prepare copper (II) sulfate crystals with copper oxide: 12.7.11.2
Prepare copper from copper oxide: 12.7.11.1
Reduce copper (II) oxide to copper with ammonia: 13.6.7
Reduce copper oxide with natural gas, methane: 16.5.1.4
Copper (II) sulfate, CuSO4
Copper (II) sulfate, CuSO4.5H2O, hydrated copper (II) sulfate 5H2O, copper (II) pentahydrate
Copper (II) sulfate solution, 0.5 M, Harmful / Slightly toxic / Poisonous if swallowed, contact with wounded skin
Copper (II) sulfate anhydrous, powder, CuSO4
Copper (II) sulfate pentahydrate, CuSO4.5H2O
Copper (II) sulfate pentahydrate, cupric sulfate pentahydrate, bluestone, copper (II) sulfate
Copper (II) sulfate anhydrous, copper (II) sulfate, cupric sulfate anhydrous, Harmful if ingested
Copper (II) sulfate pentahydrate, CuSO4.5H2O, blue vitriol, cupric sulfate pentahydrate, copper (II) sulfate hydrated, copper (II) sulfate(VI)-5-water, blue triclinic crystals efflorescent in dry air, hold on to water of crystallization in hot dry air, but anhydrous at 250 o C
Blue copperas, chalcanthite mineral, (Greek chalkos + anthos, copper flower), CuSO4.5H2O, has sweet metallic taste, blue/green, water soluble
Bordeaux mixture, copper (II) sulfate + lime, is used as a fungicide, wood preservative, "Root Eater", "Bluestone" algicide, harmful and slightly toxic
Copper (II) sulfate dissolves easily in water to form an acid solution
The crystals contain water of crystallization, which forms as steam when the crystals are heated
It is poisonous if ingested (swallowed), by skin contact, in contact with wounded skin
Use eye and skin protection (safety glasses and gloves), where splashes may occur
Do NOT breathe in copper (II) sulfate powder
If swallowed or skin contact occurs immediately flush the eye or skin or wash out the mouth with plenty of water
Some school systems do NOT allow primary children access to copper (II) sulfate solution
Show children the beautiful blue crystals
Harmful to organisms in the environment, but dispose small amounts down the sink with plenty of water
The white anhydrous copper (II) sulfate is used to test chemically for water
Copper (II) sulfate is poisonous and should not be put into vessels used in the household
Use copper (II) sulfate, bluestone, to kill algae (< 30g in 35, 000 L potable water)
Common names: Blue vitriol, cupric sulfate, "Root Kill"
Low cost: from hardware stores for drain care, root killer, also from pottery supply stores
Copper (II) sulfate, CuSO4.5H2O, bluestone, [Chalcanthite, mineral copper (II) sulfate]
Copper (II) sulfate, CuSO4.5H2O, For 0.1 M solution, 25 g in 1 L water + 5 mL conc. H2SO4
Ammonia with copper sulfate: 3.3.1
Copper (II) sulfate is insoluble in alcohol: 12.15.2
Copper (II) sulfate solution with ammonia solution, ligand substitution: 1.1
Copper (II) sulfate solution with concentrated hydrochloric acid, ligand substitution: 1.2
Copper (II) sulfate solution with magnesium: 14.3.4
Coloured precipitates, double decomposition reactions: 12.2.4.02 (See 4. copper (II) sulfate)
Decomposition of sulfates: 3.7.17 (See: CuSO4)
Distil copper (II) sulfate solution: 10.3.1
Electrolysis of copper (II) sulfate solution: 15.5.14
Electrolysis of copper (II) sulfate solution, electrochemical equivalent of copper: 15.5.19
Electrolysis of copper (II) sulfate solution, Faraday's laws: 15.5.15
Electrolysis of copper (II) sulfate solution, microscale electrolysis: 15.5.16
Electrolysis of copper (II) sulfate solution with copper and platinum electrodes: 15.6.4
Electrolysis of copper (II) sulfate solution with copper electrodes: 15.6.5
Exothermic reactions: 14.2.7
Green hair and faded hair from swimming pools: 18.2.19
Heat copper sulfate crystals: 12.2.2.4
Heat of displacement reaction, zinc with copper (II) sulfate solution: 14.1.6
Heat of reaction, anhydrous copper (II) sulfate with water: 14.3.3
Heat zinc with copper (II) oxide: 12.13.11
Iron and zinc with copper (II) sulfate solution: 12.14.12
Iron with copper (II) sulfate solution: 12.14.13
Magnesium, or zinc, with copper (II) sulfate solution: 12.14.14
Prepare copper (I) oxide with golden syrup: 12.7.11.7
Prepare copper (II) sulfate crystals with copper oxide: 12.7.11.2
Prepare copper from copper sulfate: 12.7.11.5
Prepare hydrogen gas: 13.3.4.2
Prepare iron sulfate with copper (II) sulfate solution: 12.15.3.1
Prepare preserving agents for cut flowers: 19.3.8
Prepare rayon, copper (II) sulfate with ammonia solution: 3.3.8
Prepare yellow invisible ink, with copper (II) sulfate: 12.15.1
Prepare zinc sulfate with copper sulfate solution: 12.15.3.2
Reduce copper (II) sulfate to copper sulfide, Cu2S, yellow snowstorm reaction: 12.1.41
Sodium chloride solution with copper (II) sulfate solution: 12.1.812.71.2
Tests for oxidizing agents: 15.4.17, (See: 2. and 3.)
Tests for water with anhydrouscopper (II) sulfate: 8.2.1
Zinc with lead nitrate solution, iron with copper (II) sulfate solution: 12.14.21
12.1.41 Reduce copper (II) sulfate to copper sulfide, Cu2S
The yellow snowstorm reaction
The thiosulfate ion, S2O3 2- , is a reducing agent
The cupric ion, Cu 2+ , is an oxidizing agent
The blue cupric ion., Cu 2+ may be reduced to the colourless cuprous ion, Cu +
1. Prepare a strong solution of sodium thiosulfate by heating a dozen crystals with 2 cm of water in a test-tube
Cool the solution under the tap
Add 2 cm of copper sulfate solution drop by drop
The blue colour of the copper sulfate solution fades as it mixes with the sodium thiosulfate
Heat the mixture until it begins to boil
Remove the test-tube from the flame and observe the liquid turning yellow, then brown, and finally a heavy black precipitate of copper sulfide forms
2. Equimolar ratio of sodium thiosulfate solution with copper sulfate solution
Prepare 0.5 M copper (II) sulfate solution and 0.5 M sodium thiosulfate solution and observe their colours
Mix 2 mL of each solution
Stir the mixture, observe the sudden colour change to pale green, and leave to stand
After 15 minutes a precipitate begins to form and becomes a yellow copper-thiosulfate complex, e.g. [Cu(S2O3)3]5, after 24 hours
Use a centrifuge to separate the precipitate and leave to stand separately the precipitate and the liquid
After a few days a dark layer forms on top of the yellow precipitate
Some of the thiosulfate reduces some of the copper (II) to copper (I)
3. Excess of sodium thiosulfate solution with copper sulfate solution
Add 1 mL of 0.5 M copper (II) sulfate solution to 3 mL of 0.5 M sodium thiosulfate solution
Stir the mixture, observe any colour change, and leave to stand
A dark precipitate of CuS forms after 48 hours with an iridescent coating on the inside of the test-tube
Leave for weeks and the iridescent coating becomes blue-black, thicker and darker
Test the precipitate for sulfide in a fume cupboard
Dry the precipitate, add a drop of nitric acid, hold a piece of lead acetate paper near it to become black in the presence of H2S
Some of the thiosulfate reduces all of the copper (II) to copper (I)
12.7.1.0 Reactions of copper (II) oxide, CuO
1. Mix copper (II) oxide with fusion mixture and heat it on a charcoal block in the reducing flame of a blowpipe.
Brown scales of copper forms.
2. Add concentrated hydrochloric acid to copper (II) oxide on a watch glass.
Dip a platinum wire in the mixture for a flame test.
Note the intense blue-green flame.
3. Put a borax bead on a platinum wire.
Sprinkle copper (II) oxide on the bead and heat in the oxidizing flame of a Bunsen burner.
The bead is blue then green when hot.
4. Prepare copper from copper (II) oxide.
Mix 2 mL of copper (II) oxide crystals, 2 mL of sodium hydrogen carbonate or powdered washing soda, and 4 mL of sucrose sugar crystals.
Put 2 mL of the mixture into a small metal screw cap or on a metal lid.
Heat the mixture with a Bunsen burner flame.
The mixture will swell up and form a copper-coloured mass.
To obtain the copper from the mass let the screw cap or metal lid to cool and form a copper-coloured residue.
Put the residue into a test-tube and heat it for a few minutes with dilute sulfuric acid solution.
Pour away the contents of the test-tube leaving a small amount of solid at the bottom of the test-tube.
This solid consists of small particles of metallic copper.
5. Prepare copper sulfate crystals from copper oxide.
Half fill a test-tube with dilute sulfuric acid.
Hold the test-tube with a paper holder in a flame until the liquid nearly begins to boil.
Add a small amount of black powder copper (II) oxide and observe it dissolving in the acid.
Heat the test-tube again and add further small amounts of copper (II) oxide until a black sediment of copper (II) oxide remains at the
bottom of the test-tube, even after warming for a further two minutes.
Filter the blue solution into an evaporating dish and leave it to evaporate in a cupboard.
Blue crystals of copper sulfate form.
12.7.2 Reactions of copper (II) ions, Cu 2+
1. Pass hydrogen sulfide into copper (II) sulfate solution.
Note a dark brown precipitate of copper (II) sulfide.
Cu 2+ + S 2- --> CuS (s)
Wash the precipitate and pour off excess water.
Add excess of dilute nitric acid and boil in an evaporating basin.
The copper (II) sulfide dissolves.
CuS + 2H + --> Cu 2+ + H2S (g).
2. Add potassium iodide solution to copper (II) sulfate solution.
A precipitate of white copper (I) iodide and iodine forms.
Add sodium thiosulfate solution to dissolve the iodine and note the white precipitate of copper (I) iodide.
2Cu 2+ + 4I - --> CuI2 (s) + I2 (s).
3. Add sodium hydroxide solution to copper (II) sulfate solution.
Note the blue jelly-like precipitate of copper (II) hydroxide.
Cu 2+ + 2OH - --> Cu(OH)2 (s)
Pour the jelly-like precipitate into a test-tube, add ammonia solution, NH3 (aq) and note the blue precipitate dissolving to form a deep blue solution.
This solution contains the cuprammonium ion [Cu(NH3)4] 2+ .
Ammonia has a similar reaction with silver, copper (I) and copper (II) compounds.
Boil the remaining solution and note the black precipitate of copper (II) oxide.
Cu(OH)2 --> CuO (s) + H2O.
4. Add potassium ferrocyanide solution to copper (II) sulfate solution.
Note the brown precipitate of copper ferrocyanide.
2Cu 2+ + [Fe(CN)6] 4- --> Cu2Fe(CN)6 (s).
12.7.3 Reactions of copper (I) compounds, Cu +
1. Add drops of potassium iodide solution to copper (I) chloride solution in concentrated hydrochloric acid.
Note the white precipitate of copper (I) iodide.
Cu2Cl2 + 2KI --> Cu2I2 (s) + 2KCl.
2. Pour some of the solution of copper (I) chloride in concentrated hydrochloric acid into water.
Note the white precipitate of copper (I) chloride that is soluble in a high concentration of chloride ions, but is insoluble in water.
Cu2Cl2 + 4Cl - <--> 2[CuCl3] 2- .
3. Add dilute hydrochloric acid to 2 cc of copper (I) oxide, then heat.
Note the white precipitate of copper (I) chloride.
Cu2O + 2HCl --> Cu2Cl2 + H2O.
4. Add dilute sulfuric acid to 2 cc of copper (I) oxide.
Note the red precipitate of metallic copper in a blue solution.
Cu2O + H2SO4 --> CuSO4 + Cu (s) + H2O.
5. Add dilute nitric acid to 2 cc of copper (I) oxide.
Copper from the reaction reacts with excess dilute nitric acid to form blue-green copper nitrate + nitric oxide that turns brown on exposure to air, and water.
Cu2O + 2HNO3 --> Cu(NO3)2 +H2O + Cu (s)
3Cu + 8HNO3 --> 3Cu(NO3)2 + 2NO + 4H2O.
12.7.4 Prepare copper (II) ammonium sulfate crystals
Dissolve 5 g of copper (II) sulfate in 50 mL of boiling water.
Dissolve 2.6 g of ammonium sulfate in 10 mL of water.
Mix the solutions and evaporate until crystallization begins, then set aside to cool.
The crystals are a double salt.
CuSO4 (aq) + 4 NH4OH (aq) --> Cu(NH3)4SO4H2O (s) + 3 H2O (l)
Copper (II) ammonium sulfate crystals, (NH4)2SO4.CuSO4.6H2O
12.7.5 Prepare cuprammonium sulfate
Cuprammonium sulfate, | Cu(NH3)4SO4 | [Cu(NH3)4]SO4·H2O | [Cu(NH3)4(H2O)]SO4| , tetraamminecopper (II) sulfate monohydrate
Dissolve 10 g of copper (II) sulfate by boiling in 50 mL of water in a 200 mL flask and leave to cool.
Slowly add concentrated ammonia solution, NH3 (aq) ("ammonium hydroxide") until any precipitate redissolves, then leave to cool.
Be careful!.
Add 20 mL of ethanol to form a layer on top of the blue solution.
Stopper the flask loosely and leave undisturbed for a week.
Filter off the crystals of cuprammonium sulfate and transfer to a container with a stopper.
Cuprammonium sulfate is a complex salt in which the copper ion and ammonia form a single divalent ion [Cu(NH)] 2+ ].
12.7.6 Prepare copper (I) oxide
1. Use a 5 cm square of shiny copper foil.
Fold in the corners of the square then hammer the corners flat.
Use tongs to heat the pieces of copper foil in a Bunsen burner flame.
The heated foil turns black as a layer of black copper (I) oxide forms on it.
Use pliers to open the folded corners so that you have restored the 5 cm square again.
The area of copper foil where the corners were folded over is still shiny, because the copper had no access to the oxygen in the air.
2Cu (s) + O2 (g) --> 2CuO (s)
copper + oxygen --> copper (I) oxide.
2. Fill a boiling tube to the depth of 2 cm with copper (II) sulfate solution and add 2 cc of Rochelle salt, sodium potassium tartrate.
When the salt has dissolved, add sodium hydroxide solution.
The solution is now Fehling's solution.
Add 2 cc of glucose and boil.
An orange-red precipitate of copper (I) oxide forms by the reducing action of glucose on the copper (II) copper in solution.
2Cu(OH)2 - O --> Cu2O + 2H2O
Reduction by glucose.
The precipitate is soluble in concentrated hydrochloric acid, but dilute sulfuric acid or nitric acid gives free copper and the copper (II) salt.
Excess nitric acid acts on the copper.
Cu2O + 2HCl --> CuCl2 + H2O
Cu2O + H2SO4 --> Cu + CuSO4 + H2O.
12.7.7 Prepare copper (I) chloride, CuCl
Copper (I) chloride, CuCl, cuprous chloride
Copper (II) chloride (CuCl2)
Cuprous chloride, CuCl, was first produced by heating mercury (II) chloride with copper, leaving CuCl and Hg, dangerous experiment!
1. Use enough copper (II) oxide to cover the bottom of a test-tube.
Add five times that volume of concentrated hydrochloric acid then heat the solution.
Note the green copper (II) chloride solution.
CuO + 2HCl --> CuCl2 + H2O
Add copper filings of equal volume to the copper (II) oxide used, and boil for 2 minutes.
Filter the mixture through glass wool into a beaker of water.
Note the white precipitate of copper (I) chloride.
Cu + CuCl2 --> Cu2Cl2 (s)
(Cu2Cl2 is by joining two identical molecules by bonds between cuprous (I) chloride, CuCl)
Pour off the supernatant liquid into two parts.
Use part A to show that the copper (I) chloride is soluble in ammonia solution, NH3 (aq) ("ammonium hydroxide"), because of the
formation of a complex ion.
Cu2Cl2 + 4NH3 --> 2[Cu(NH3)] 2+ + 2Cl -
Use part B to show that the copper (I) chloride is soluble in concentrated hydrochloric acid, because it forms of another complex ion with the chloride ion.
This complex ion is unstable and decomposes on dilution with water.
Cu2Cl2 + 4Cl - --> 2[CuCl3] 2- .
2. Prepare dry copper (I) chloride with a filter pump and Buchner funnel to get the white solid.
Wash it with sulfurous acid then glacial acetic acid, then dry it by heating on a water bath.
Keep the dry solid in a sealed container.
12.7.8 Recycle copper
1. Precipitate insoluble metal salts with sodium carbonate, sodium hydroxide or sodium sulfide.
Decant the clear solution above the precipitate and wash it down the sink.
Store the dried precipitate.
2. Add iron filings or steel wool or nails or any waste iron to displace copper from solution.
Decant the clear solution above the precipitate and wash it down the sink.
Store the dried precipitate.
12.7.9.0 Oxidize copper foil or a copper coin
In the UK, it is illegal to use the king's coinage for any purpose except that of currency.
So if you live in the UK and you want to be on the right side of the law, use a foreign coin for this experiment!
1. Hold the copper foil by the edge with pair of pliers and heat it at the tip of a hot flame.
The surface of the copper turns black, because the copper combines with oxygen in the air to form black copper (II) oxide, cupric oxide, CuO.
After heating for a few minutes, leave the copper to cool, then scratch it with a knife point.
A red layer below the black layer is copper (I) oxide, cuprous oxide, Cu2O.
Below the red layer is unchanged copper, Cu.
Put the blackened copper in a beaker and warm it with dilute sulfuric acid.
The surface of the coin becomes clean and a blue solution of copper sulfate forms.
The surfaces of copper coins become black with age.
The blackening is because copper combines with oxygen and hydrogen sulfide gases in the atmosphere to form black copper oxide and black copper sulfide.
Remove the black coating with dilute nitric acid.
Dilute sulfuric acid dissolves the copper oxide, but not the copper.
2. Place the blackened coin in a beaker and warm it with a little dilute sulfuric acid, sodium bisulfate solution, or dilute nitric acid.
The surface of the coin will be cleaned, and a blue solution of either copper sulfate or copper nitrate forms.
The surfaces of copper coins in everyday use become black with age
The copper in the coin combines with oxygen and hydrogen sulfide gases in the atmosphere to form copper oxide and copper sulfide, which are both black.
The black coating can be removed and the discoloured coin made bright and shiny by warming with dilute nitric acid.
Dilute sulfuric acid will dissolve the copper oxide, but not the copper sulfide.
12.7.10 Prepare copper from brass
1. Heat a piece of brass in a test-tube half full of dilute nitric acid.
Effervescence begins.
Observe the brown-yellow gas in the test-tube.
At the same time a green-blue solution of copper nitrate forms.
Let the action continue for five minutes and then pour the solution into an eggcup.
Put a clean penknife blade into the solution.
A deposit of pure copper forms on the blade.
The gas is a mixture of colourless nitrogen tetroxide, nitrogen peroxide, N2O4 with red-brown nitrogen dioxide, NO2.
N2O4 <--> 2NO2.
2. This experiment can also be done with a small copper coin.
Warm a small piece of brass or a few bits of brass wire in a test-tube half full of dilute nitric acid, using only a small flame.
Soon effervescence will begin and a brown gas, nitrogen peroxide, will be seen in the tube.
At the same time a green-blue solution of copper nitrate forms.
Allow the action to proceed for about five minutes and then pour the solution into an egg cup.
Put a clean penknife blade into the solution.
A deposit of pure copper forms on the blade.
12.7.11.0 Tests for copper wire with a flame test
Dip the end of a copper wire into an iodine solution or tincture of iodine, then into the edge of a flame.
Observe a blue-green colour of the flame, a beautiful appearance in the dark.
12.7.11.1 Prepare copper from copper oxide
Mix one part of copper oxide, sodium bicarbonate or powdered washing soda, and two parts of sugar.
Put a small amount of the mixture into a small metal screw-cap or on to a tin lid.
Heat the mixture over a medium Bunsen flame.
The mixture swells up and forms a copper-coloured mass.
To obtain the copper from the mass allow the screw-cap or lid to cool and powder the copper-coloured residue.
Put the powder into a test-tube and warm it for a few minutes with a little dilute sulfuric acid or sodium bisulfate solution.
Pour away the contents of the tube except for the small amount of solid left at the bottom of the tube.
This solid contains small particles of metallic copper.
12.7.11.2 Prepare copper (II) sulfate crystals with copper oxide
When black copper oxide is warmed with dilute sulfuric acid, it is converted into a blue solution of copper sulfate.
Half fill a test-tube with dilute sulfuric acid.
Holding the tube in a paper holder, warm it over a small flame until the liquid nearly begins to boil.
Then add a pinch of copper oxide from a salt spoon to the tube.
The black powder will dissolve.
Warm the tube again and add a further pinch of copper oxide.
This also will dissolve.
Continue the adding of small amounts of copper oxide and warming until a black sediment of copper oxide stays at the bottom of the tube, even after warming.
Filter the blue solution into an evaporating dish and leave it to evaporate in the bottom of the airing cupboard.
Blue crystals of copper sulfate will be deposited in a few hours on the bottom of the dish.
12.7.11.3 Prepare copper (II) sulfate algicide.
1. Copper (II) sulfate solutions are blue only at concentrations greater than about 50 ppm.
Copper ions at concentration 0.05 mg / L (0.05 ppm) of depress cell division and photosynthesis in common freshwater green alga, e.g. Chlorella pyrenoidosa.
Copper (II) sulfate pentahydrate, CuSO4.5H2O, has a molar mass of 249.5 g / mol.
Copper has a molar mass of 63.5 g / mol.
To make a 1000 mg / L of Cu 2+ solution (1000 ppm), use 249.5/63.5 = 3.929 g of copper (II) sulfate pentahydrate per litre of distilled water or deionized water.
Use this solution to prepare serial dilutions (1:10) to reduce this concentration to 100, 10, 1, 0.1 ppm Cu 2+ .
Use a fluorescent tube of colour temperature 6500 K whiteness of colour.
See: 23.8.21 Colour temperature.
2. Effect of pH on the toxicity of copper
At pH below 7.0, the toxicity of copper is greatly enhanced.
Prepare solutions of desired pH by diluting some 0.1 M hydrochloric acid (pH 1).
Add standard copper solution to produce a 1 ppm concentration of copper.
3. Effect of other metals on the toxicity of a copper algicide
Toxicity of ionic copper on algal growth is reduced by trivalent (3+)
metal ions, including those of Mn, Co, Al, Fe and Cr.
They form a layer of metal (III) hydroxide around the algal cell, adsorb copper and reduce the penetration of copper into the cell.
The degree of insolubility of the metal (III) hydroxide is related to its ability to protect against copper toxicity.
Test different metals while keeping the Cu 2+ concentration the same.
4. Effect of availability of copper on the toxicity of a copper algicide
The two types of algicides sold are 1. ionic copper, a 5% CuSO4 solution (5 g copper (II) sulfate / 100 mL) and 2. chelated copper (about 7% Cu).
Chelated copper such as copper alkanolamine complex is more toxic to algae than ionic copper, because both the metal and the organic ligand enter the algae cell.
Also, chelated copper is more resistant to changes in pH.
Test the algicide ability of both forms of algicide at the same concentration of Cu 2+ , and compare them at different pH.
Chelated copper remains active algicide for several weeks whereas copper (II) sulfate remains active only for a few days.
If pool water contains high concentration of carbonate ions, copper ions in copper (II) sulfate react with carbonate ions and form insoluble copper carbonate.
12.7.11.5 Prepare copper from copper sulfate
1. Shake iron filings with 2 cm of blue vitriol solution in a test-tube for a few minutes.
The colour of the solution will fade, and, if the shaking is continued long enough, will disappear.
Filter the contents of the tube.
Note the red-brown powder left in the filter paper.
copper sulfate + iron --> copper + iron sulfate
The red-brown powder is not pure copper, because excess of iron filings is a mixture of copper and excess iron filings coated with copper.
2. Repeat the experiment using a piece of lead instead of iron filings.
After cleaning the lead rub it with sandpaper and then immerse it in hot copper sulfate solution.
The heat is necessary, because the action is slow in the cold.
A film of copper will be deposited on the lead.
12.7.11.7 Prepare copper (I) oxide with golden syrup
1. Add sodium hydroxide solution to 2 cm of copper (II) sulfate solution.
A blue jelly-like precipitate of copper hydroxide forms.
Stir golden syrup on the end of a spoon into a little hot water until it has dissolved.
Add 2 cm of this solution to the copper hydroxide precipitate in the test-tube.
Heat the test-tube gently.
A yellow precipitate of copper (I) oxide, CuO, forms in the test-tube.
The colour gradually changes to orange.
Filter off the precipitate.
The copper (I) oxide is left in the filter paper turns red, its usual colour.
2. Repeat the experiment with a solution of black treacle, or the sweet sold as "barley sugar".
These foods contain glucose.
This chemical action may be used as a test for glucose.
3. Use the solution to test on a cut apple for glucose.
Heat small pieces of the apple with water.
After filtering the liquid, use it in the same way as described for the golden syrup solution above.
2NaOH (aq) + CuSO4 (aq) --> Na2SO4 (aq) + Cu(OH)2 (s).
12.15.1 Prepare yellow invisible ink, with copper (II) sulfate
Copper (II) sulfate with ammonium chloride
Add 1 mL of powdered copper (II) sulfate and 1 mL of ammonium chloride to a test-tube nearly full of water.
Dissolve the substances by holding the thumb over the end of the test-tube and shake the test-tube upside.
Use a small paint brush to write on a piece of paper with the faint blue solution.
When the writing has dried, it is invisible.
Warm the paper in front of a flame to make the writing appear in yellow letters.
CuSO4.5H2O + 2NH4Cl --> (NH4)2SO4 + CuCl2 + 5H2O
Copper (II) chloride solution is green-blue.
12.15.2 Copper (II) sulfate is insoluble in alcohol
Make a strong solution of copper sulfate by heating 1 cm of the powder with 2 cm of water in a test-tube.
When the powder has dissolved, cool the test-tube under the tap.
Pour drops of methylated spirits into the test-tube.
A shower of very small crystals of copper sulfate precipitates in the test-tube, because copper sulfate is insoluble in methylated spirit.
12.15.3.1 Prepare iron sulfate with copper (II) sulfate solution
1. Shake 2 mL of iron filings with 4 cm of copper sulfate solution in a test-tube for a few minutes.
The colour of the solution will fade.
If the shaking continued for long enough the colour disappears.
Filter the contents of the test-tube.
A red-brown powder is left in the filter paper as the more reactive Fe, displaces Cu to form FeSO4 and Cu.
Fe (s) + CuSO4 (aq) --> FeSO4 (aq) + Cu (s)
iron + copper sulfate --> iron (II) sulfate + copper
The red-brown powder is not pure copper, because the excess iron filings is a mixture of copper and excess iron filings coated with copper.
12.15.3.2 Prepare zinc sulfate with copper sulfate solution
Zinc metal can displace copper ions from a solution of copper (II) sulfate.
Add excess zinc powder to copper (II) sulfate solution.
Zn (s) + CuSO4 --> ZnSO4 + Cu
Zn (s) + Cu 2+ (aq) --> Zn 2+ (aq) + Cu (s)
Zn (s) + Cu 2+ (aq) + SO4 2- (aq) -->
Zn 2+ (aq) + SO4 2- (aq) + Cu (s)
[SO4 2- is a "spectator ion".]
12.15.3.3 Prepare lead sulfate with copper sulfate solution
After cleaning the lead, rub it with sandpaper, then immerse it in very hot copper sulfate solution.
The heat is necessary, because the action is slow in the cold.
A film of copper deposits on the lead.
Pb (s) + Cu 2+ (aq) + SO4 2- (aq) --> Pb 2+ (aq) + SO4 2- (aq) + Cu (s)
Pb 2+ (aq) + SO4 2- (aq) --> PbSO4 (s)
However, the lead sulfate is insoluble in the solution and rapidly forms a layer on the lead strip.
So most people think no reaction occurs.
12.15.4 Prepare copper (II) carbonate and copper (II) oxide
Add 2 cm of copper sulfate solution to 2 cm of sodium carbonate solution.
A blue-green precipitate of copper carbonate forms in the double decomposition reaction
Filter the precipitate, and with a spill transfer it to a metal lid.
Hold the lid in a pair of pliers and warm it gently over a small flame.
The green colour copper (II) carbonate will change to black, because of formation of black copper (II) oxide.
2Na + + SO4 2- + Cu 2+ + CO3 2 - --> Na2SO4 + CuCO3
Na2CO3 + CuSO4 --> Na2SO4 + CuCO3
sodium carbonate + copper sulfate --> sodium sulfate + copper (II) carbonate
Another explanation:
2Na2CO3 +2CuSO4 + H2O --> 2Na2SO4 + Cu2(OH)2CO3 + CO2
sodium carbonate + copper sulfate + water --> sodium sulfate + basic copper carbonate + carbon dioxide
Cu2(OH)2CO3 = 2CuO + CO2+ H2O.
12.15.5 Heat copper foil to form copper (II) oxide
Copper (I) oxide, Cu2O, cuprous oxide
Copper (II) oxide, CuO, cupric oxide, copper oxide
Copper (I) oxide produced by the oxidation of copper metal
4 Cu + O2 --> 2 Cu2O
Cleaned copper is brown red.
In moist air the surface turns green due to oxidation.
The green surface is called a patina.
It also forms on old unpolished bronze.
1. Heat a narrow strip of copper foil, for half a minute, using the test-tube holder, so that only a small part of the foil is in the flame.
Describe what happens to the metal.
The metal does not melt.
The heated part turns black.
The spirit burner flame is not hot enough to melt the copper.
The part of the metal in the flame becomes covered with black copper oxide.
2. Tests for copper (II) oxide formation
Clean a piece of copper foil with steel wool.
Hold it in a flame with a pair of tongs.
The copper foil turns black.
The black copper (II) oxide looks like carbon.
To test the substance, drop dilute sulfuric acid on it, then heat it.
Blue copper (II) sulfate forms.
Test some powdered carbon.
No colour change occurs.
2Cu + O2 --> 2CuO
copper (s) + oxygen (g) --> copper oxide (s).
3. Clean a piece of copper foil with steel wool.
Hold it in a flame with a pair of tongs.
The black copper (II) oxide looks like carbon.
To test the substance, drop dilute sulfuric acid on it, then heat it.
Blue copper (II) sulfate forms.
Test some powdered carbon.
No colour change occurs.
4. Show that something is added to the copper from the air.
Use a sensitive balance to weigh the copper before and after heating.
5. Use two identical hard glass test-tubes with one-hole stoppers fitted with bent delivery tubes.
Fix both test-tubes to a stand so that the test-tubes slope down with the ends of the delivery tubes under water in a beaker.
Put copper foil in the first test-tube and heat with a hot burner flame.
After two minutes, heat the empty second test-tube.
Move the burner regularly between the two test-tubes until no more bubbles come out of the ends of the delivery tubes.
Stop heating both test-tubes.
As the test-tubes cool, they suck water up the delivery tube.
The test-tube containing the copper (II) oxide sucks up more water.
10.1.3 Prepare copper (II) carbonate
Dissolve a finger width of copper sulfate in a test-tube half filled with water.
Dissolve a finger width of sodium carbonate in another test-tube half filled with water.
Shake each test-tube to help the chemicals dissolve.
Add the two liquids by pouring one into the other.
A blue-green solid substance forms, copper carbonate.
Filter the mixture from the previous experiment that contains the blue-green solid.
Copper carbonate remains on the filter paper.
Pour half a test-tube of hot water onto the copper carbonate to wash away other substances.
Remove the filter paper from the filter funnel, open it and lay it on a flat surface and leave to dry.
Store and label the dry copper carbonate.
Na2CO3 + CuSO4 -->Na2SO4 + CuCO3
sodium carbonate + copper sulfate ---> sodium sulfate + copper carbonate
12.3.5.01 Copper oxide with sodium hydrogen sulfate
Add half a test-tube of sodium hydrogen sulfate solution to copper oxide in a test-tube.
Heat the solution slowly until it turns blue.
Be careful of spurting from the test-tube.
Some copper oxide may remain after the reaction.
Filter the solution obtain the filtrate of copper sulfate solution.
12.11.3.19 Tests for copper
1. Ammonium hydroxide gives a pale blue precipitate that dissolves in excess to give a deep blue solution.
2. Organic reagent: Rubeanic acid (ethanedithioamide, dithiooxamide), NH2.CS.CS.NH2, saturated 0.5% alcoholic solution
Use 10 mL of neutral Cu solution + 1 mL 5M CH3COOH + drops of reagent.
A green-black precipitate forms.
Test with Group II precipitate.
Ni and Co may interfere with the test.
Dissolve CuS in dilute HNO3 and neutralize with NaOH solution.