School Science Lessons
2024-04-16
Calcium, Ca
Contents
See: Calcium, Table of the Elements
See: Calcium, RSC
Calcium experiments
Calcium, properties
Calcium compounds
6.12.1 Calcium deficiency in soils
Tests for milk fortification with calcium carbonate
Calcium toxicity
Concrete
12.14.5 Superphosphate production
3.71.2 Calcium experiments
Chalk: 35.22.3, Geology
Chalk (lime) content of the soil: 6.9.02
Group 5 tests for Ba2+, Ca2+, Sr2+: 12.11.4.5
Heat calcium metal to form calcium oxide: 8.2.14
Reactions of calcium and calcium compounds: 12.4.1
Tests for calcium: 16.5.5
Tests for calcium (flame test): 12.11.3.16
Weight of calcium in marble: 17.6.3
3.71.3 Calcium properties
Calcium, Ca (Latin calx lime), alkaline earth metal, calcium ion Ca2+, in many natural compounds and living organisms, burns with brilliant light, fifth most abundant element
Calcium, metal, granulated, granules, shot, pieces, AAS Solution, Toxic if ingested or by skin contact
Decalcifying Solution is used for the decalcification microscopy sections and bone marrow core specimens is an alkaline earth metal, granules in liquid paraffin
Reacts with dilute HCl or H2SO4 to form H2 and metal ion, occurs mainly as carbonates, e.g. calcium carbonate, CaCO3, gypsum,
CaSO4.2H2O, 3.5% of the earth's crust, essential nutrient element for bones,
teeth and muscle contraction in animals and middle lamella of plant cells, extracted by electrolysis of fused calcium chloride
Calcium reacts with concentrated oxidizing acids, HNO3 or H2SO4 to produce high oxidation number ions, and sulfur dioxide, SO2, or nitrogen dioxide, NO2
Reacts with cold water and reacts with air to form peroxides
Calcium is the most abundant mineral, and the fifth most abundant element mostly in bone tissue
About 1% is used in nerve transmission, muscle contraction and other functions
Atomic number: 20, Relative atomic mass: 40.08, r.d. 1.54 g cm-3| m.p. = 850oC, b.p. = 1487oC
Specific heat capacity: 653 J kg-1 K-1
12.4.1 Reactions of calcium and calcium compounds
1. Heat a flake of calcium on wire gauze with a Bunsen burner flame
The calcium burns brilliantly with a red flame and leaves a white residue of calcium oxide
Add drops of water to the calcium oxide in a test-tube and note the vigorous exothermic reaction
Test the solution with red litmus paper that turns blue
Note that calcium oxide is not very soluble in water
2Ca + O2 --> 2CaO
CaO + H2O --> Ca(OH)2 (s)
2. Drop a small piece of calcium (not old stock calcium) into a test-tube a quarter full of dilute hydrochloric acid
Press your thumb over the mouth of the test-tube and when you can feel the pressure on your thumb test the gas for hydrogen with a lighted splint
Repeat the experiment with a small piece of magnesium ribbon
The same reaction occurs, but the calcium is obviously more reactive, because it slower down group 2 of the periodic table
Usually, the lower an element in the same group of the periodic table, the more reactive it is
Ca + 2HCl --> CaCl2 + H2
Mg + 2HCl --> MgCl2 + H2
3. Add ammonium carbonate solution to calcium chloride solution
Note the white precipitate of calcium carbonate
Ca2+ + CO32- --> CaCO3 (s.)
4. Add ammonium oxalate solution to calcium chloride solution
Note the white precipitate of calcium oxalate that is soluble in dilute hydrochloric acid, but insoluble in acetic acid
Ca + C2O42- --> CaC2O4 (s)
5. Add solutions of calcium salts to potassium chromate solution and to calcium sulfate solution
No precipitate forms with calcium sulfate solution and barium salts with potassium chromate solution
6. Add sodium phosphate solution to calcium chloride solution
Note the white precipitate of calcium phosphate that is soluble in dilute hydrochloric acid, nitric acid or acetic acid
3Ca + 2PO43- --> Ca3(PO4)2 (s)
7. Add concentrated hydrochloric acid to dry calcium chloride and do the flame test
Note the brick-red flame and observe the green colour when seen through blue glass
Calcium compounds
Calcium compounds, calcareous minerals, calcareous clay, marl, calcareous rock
Actinolite, Ca2(Mg, Fe2+)5(Si8, O22)(OH, F)2, (Geology)
Anhydrite, calcium sulfate anhydrous, CaSO4, "snake alabaster"
Apatite, Ca5(PO4)3(OH,F,Cl):
35.21.3.1 (Geology)
Aragonite, CaCO3, calcium carbonate (pea stone in hot springs), Dimorphism (Geology)
Bustamite, MnCaSiO6, manganese silicate: 35.3.3.1 (Geology)
Dolomite, CaMg(CO3)2: 35.19.1 (Geology)
Calcium acetate H2O, CaC4H6O4, calcium acetate monohydrate, calcium diacetate
Calcium acetate, Metallic salts gels: 7.8.5.4
Calcium bromide, CaBr2
Calcium carbide, CaC2
Calcium carbonate
Calcium chlorate (I) (in bleaching powder with calcium hypochlorite)
Calcium chloride
Calcium chromate, CaCrO4, yellow powder, slightly soluble in water
Calcium citrate (tribasic tetrahydrate)
Calcium copper silicate, CaCuSi4O10, cuprorivaite, Egyptian blue, caeruleum, ancient pigment
Calcium cyanamide, CaCN2, nitrogen fertilizer
Calcium dicarbide, CaC2, calcium carbide, calcium acetylide, carbide
Calcium dihydrogen phosphate Ca(H2PO4)2, monohydrate Ca(H2PO4)2, harmful if ingested in excess
Calcium fluoride, calcium fluorite, fluorspar, Harmful if ingested
Calcium fluorophosphate dihydrate, CaFO3P.2H2O
Calcium hydride, CaH2
Calcium hydrogen carbonate, calcium bicarbonate
Calcium hydride, CaH2, reducing agent to produce metals from metal oxides, hydrolith, Toxic if ingested or by skin contact
Calcium hydrogen phosphate, calcium hydrogen orthophosphate (dihydrate), dicalcium phosphate, Harmful
Calcium hydroxide, Ca(OH)2, slaked lime
Calcium hydroxyapatite, dental enamel, Ca5(PO4)3(OH), Ca10(PO4)6(OH)2: 9.226
Calcium hypochlorite
Calcium hypophosphite, H4CaO4P2
Calcium hyroxyapatite, calcium hydroxyl apatite, Ca10(PO4)6(OH)2, Teeth and toothpaste: 9.226
Calcium iodate, CaI2O6
Calcium iodide, CaI2
Calcium lactate, C6H10CaO6, baking powder E327, calcium lactate 5-hydrate, in cheese, prevent tooth decay
Calcium magnesium acetate (CMA), De-icers
Calcium magnesium carbonate, dolomite CaMg(CO3)2: 35.19.1 (Geology)
Calcium magnesium carbonate, CaCO3MgCO3, dolomite, [but "dolomite" is any high Mg: Ca carbonate rock]
Calcium malonate in beetroot
Calcium manganese silicate, bustamite, MnCaSiO6: 35.3.3.1 (Geology)
Calcium metaborate, B2CaO4.2H2O
Calcium nitrate, Ca(NO3)2
Calcium nitrite, CaN2O4
Calcium octadecanate, calcium stearate, Ca[CH3(CH2)16COO]2, hard water scum on bath tubs
Calcium orthophosphate, Harmful if ingested
Calcium oxalate, CaC2O4, raphides
Calcium oxide, CaO, quicklime
Calcium perchlorate, CaCl2O8
Calcium phosphate
Calcium phosphide, solid, active phoshor, Ca3P2, in incendiary bombs, rat poison "Photophor", Toxic if ingested or by skin contact
Calcium phosphide, Solution < 0.1% Not hazardous
Calcium plumbate, formerly in lead-based priming paint, lead poisoning if children eat old paint scales
Calcium polysulfide, lime sulfur, CaSx (CaOH + S), agricultural fungicide: 4.3.1
Calcium sulfate, CaSO4, gypsum
Calcium sulfite, food additive, preservative, firming agent E226
Calcium tetrahydrogen phosphate (V), calcium hydrogen orthophosphate, secondary calcium phosphate
Calcium tetrahydrogen diorthophosphate
Calcium thioglycollate
Calcium trifluoromethanesulfonate, C2CaF6O6S2
Calcium tungstate, CaWO4 (in cathode ray tubes), scheelite: 35.20.38 (Geology)
Calcite, Calcium carbonate
Calcium carbonate CaCO3
Calcium carbonate, CaCO3, powder, almost insoluble in water unless dissolved CO2 present, calcite, chalk, limestone, Iceland spar, marble chips, whiting, calc-spar, pearl, coral, egg shells, whitewash, calcimine, seashells, (in antacid medicines to suppress reflux), Vienna lime, E170 firming agent, food additive, heated in a lime kiln to form lime CaO, powdered abalone or oyster shell used as folk medicine (school chalk, but usually school chalk is calcium sulfate)
Calcium carbonate, marble chips, precipitated, aragonite, carbonate of lime, [calcite, Iceland spar]
Calcium carbonate, limestone (pea stone in hot springs), chalk (lime), with HCl forms CO2
Aragonite, CaCO3, calcium carbonate (pea stone in hot springs), Dimorphism, (Geology)
Calcite, CaCO3, Calc-spar, Iceland spar: 35.19.0, (Geology)
Calcite crystals, Birefringence: 28.181
Calcium carbonate gel, Metallic salts gels: 7.8.5.4
Calcium carbonate, limestone, calcarenite, marble, hard water calcination deposit, tennis court marking lime
Calcium carbonate dissolves in rain water: 35.22.7.1, (Geology)
Carbon dioxide through calcium carbonate suspension: 12.16.1
Chalk: 35.22.3, (Geology)
Chalk (lime) content of the soil (Agriculture): 6.9.02
Dilute hydrochloric acid with calcium carbonate: 12.3.9.1, (Geology)
Dilute hydrochloric acid with marble chips, Particle size: 17.2.1
Dilute hydrochloric acid with marble chips (balloons to collect gases): 17.1.4
Dilute hydrochloric acid with marble chips, gas burette: 17.1.3
Langelier saturation index: 18.7.43, (swimming pools)
Lime, CaO
Lime, limewater, limestone
Low cost: whiting, from pottery supplies stores, some antacid powders, building stores for crushed marble
Marble, marble chips, 4-6 mm, 9-12 mm: 35.23.3, (Geology)
Putty: 34.68.0
Tests for limestone: 35.31 (Geology)
Tests for carbohydrates, Molisch's test (α-naphthol test): 9.134
Tests for carbonates: 12.11.5.7
Weight of calcium in marble, calcium carbonate: 17.6.3
Plasticine "Plasticine", modelling clay, is said to contain calcium carbonate, stearic acid, petroleum jelly, whiting, ten pigments, formerly "Harbutt's plasticine", "Plastilina" is a similar product
Common names: chunks: marble, limestone, powder: precipitated chalk
Calcium carbonate CaCO3
Carving stones, Limestone, stone dust and carving stones: 35.22.7 (Geology)
Chalk
Dolomite, CaMg(CO3)2: 35.19.1 (Geology)
Drierite drying agent, with moisture indicator, CaO4S
Fluorite, fluorspar, fluoride, CaF2, (Geology)
Gypsum, calcium sulfate, plaster of Paris, CaSO4.2H2O (Geology)
Hornblende: 35.17.0 (Geology)
Lime sulfur, CaSx: 16.6.12, (Fungicide, acaracide and insecticide) (Agriculture)
Marble, CaCO3: 35.23.3, (Geology)
Montmorillonite (smectite), Fuller's earth, bentonite: 35.22.4.3 (Geology)
Plasticine, modelling clay
Scheelite crystals, calcium tungstate, CaWO4: 35.20.38 (Geology)
Tanzanite, Ca2(Al3)(Si2O7)(SiO4)O(OH): 35.20.52 (Geology)
Calcium carbide CaC2
Calcium carbide, calcium dicarbide, calcium acetylide, carbide, acetylenogen, ethnide dicarbide, Toxic by all routes
Calcium carbide, called "carbide", acetylenogen, was used in carbide lamps in cave explorer lamps, formerly in bicycle headlamps and underground mines
Many fires and explosions resulted from these lamps and they are now rarely used
The main hazard with calcium carbide is the ignition of air / acetylene mixtures
A violent explosion may occur, depending on the proportions of air and acetylene
Acetylene, when undiluted with air, burns with a smoky flame
Before igniting acetylene, be sure that it is NOT mixed with air
Calcium carbide usually contains sulfur and phosphorus compounds that react with water to form strongly smelling gaseous impurities.
Calcium chloride, CaCl2
Calcium chloride anhydrous, granular, CaCl2
Calcium chloride dihydrate, CaCl2.2H2O
Calcium chloride, fused, dried calcium chloride (1.5-2.5 mm)
Calcium chloride hexahydrate, CaCl2.6H2O
Calcium chloride monohydrate, CaCl2.H2O
Calcium chloride, anhydrous, CaCl2, 0.l M solution, 11 g in 1 L water
Calcium chloride, CaCl2.2H2O, For 0.1 M solution, 14.7 g in 1 L water
De-icers, ice melts: 7.4.3.3
Low cost: ice melt products, from brewing / wine making supply stores, garden stores as trace nutrient fertilizers
Soft water, low calcium content, cause etching of swimming pool surfaces, increase with calcium chloride
Calcium chloride
Calcium chloride, anhydrous, granular, CaCl2, white granules or lumps, very hygroscopic, m.p. 772oC (drying agent, desiccant), E509,
used to form calcium metal, sold as laundry
booster, de-icing chemical, Harmful if ingested
Calcium chloride dihydrate, CaCl2.2H2O
Common names: Laundry aid, laundry salt, road salt (de-icing agent but must be pure calcium chloride)
Calcium dihydrogen phosphate, CaH4P2O8
Calcium dihydrogen phosphate (V), calcium tetrahydrogen di-orthophosphate, calcium dihydrogen phosphate, Calcium bis(dihydrogen phosphate), E341, leavening agent in baking powders
Calcium fluoride, CaF2
Calcium fluoride, fluorite, fluorspar, Blue John, white crystalline solid, thermoluminescent, for craft, fluoridated tooth paste, source of hydrofluoric acid and fluorine, in opal glass
Calcium fluoride, fluorspar, fluorite, blue john, Derbyshire spar, fluorspar, CaF2: 35.20.14 (Geology)
Prepare hydrogen fluoride, HF: 12.19.7.1
Calcium hydrogen carbonate, Ca(HCO3)2
Calcium hydrogen carbonate, calcium bicarbonate, temporary water hardness, stable in solution
Calcium hydrogen carbonate, Temporary (water) hardness and permanent hardness: 12.13.0.1
Dilute acids with calcium hydrogen carbonate: 12.3.10.1
Calcium hydroxide, Ca(OH)2
Calcium hydroxide, 0.02 M, saturated solution, 1.5 g Ca(OH)2 per litre
Common names: slaked lime, garden lime, caustic lime
Calcium hydroxide, Ca(OH)2, slightly soluble powder, solution called "limewater" or "milk of lime", garden lime, E526.
Calcium hydroxide solution, calcium hydroxide powder (limewater, lime), slaked lime, Harmful if ingested
Whitewash, calcimine, kalsomine, whiting, is a lime paint made from calcium hydroxide or calcium carbonate,.
It was much used in the army, institutions and as a poor man's house paint.
It may react with carbon dioxide in the air to form a hard coat.
Experiments
Carbon dioxide with calcium hydroxide solution: 12.16.1.1
Low cost, from garden supply stores, as hydrated lime, slaked lime, lime, may also contain CaO or CaCO3.
Prepare limewater: 5.4.5
Prepare quicklime, CaO: 34.17
Prepare slaked lime, Ca(OH)2: 34.18
Calcium hypochlorite, Ca(OCl)2
Calcium hypochlorite: 18.7.2.2.1
Calcium hypochlorite, hydrated, bleaching powder, chlorinated lime, Toxic by all routes
Calcium hypochlorite, Solution < 5%, Not hazardous
Calcium hypochlorite dry, for swimming pools, "dry pool chlorine", Toxic by all routes
Prepare trichloromethane (chloroform): 16.1.14
Calcium hypochlorite
Calcium hypochlorite, Ca(OCl)2, bleaching powder (technical grade: available chlorine, 65%), bleaching agent, chlorinated lime, chloride of lime, calcium oxychloride grey-white powder, irritating odour,
exothermic when dissolved in water, may explode if NOT
stored securely (bleaching powder contains both calcium hypochlorite, [calcium chlorate (I), chlorinated lime] and calcium hydroxide, water
sanitizing, whitening agent, "solid chlorine" is 70% chlorine for swimming pools)
Bleaching powder forms chlorine gas that is highly irritant to the lungs
If acid is added to bleaching powder, large amounts of chlorine are produced
The mixture becomes hot and may boil violently
Do not add concentrated ammonia to bleaching powder, because nitrogen trichloride, NCl3, may form
This is a violently unstable liquid, liable to explode without apparent reason
Bleaching powder is a convenient source of chlorine gas for other experiments.
Add dilute hydrochloric acid from a dropping funnel to a slurry of bleaching powder and water, in a conical flask fitted with a rubber stopper and gas collection system
Keep a solution of sodium hydroxide nearby to stop the reaction
Adding sodium hydroxide solution to the mixture does not pose any problems
Dispose of the waste mixture by diluting it with water and washing it down the drain
Calcium nitrate, Ca(NO3)2
Calcium nitrate, Ca(NO3)2.4H2O, calcium nitrate (V)-4-water, crystals
Calcium nitrate tetrahydydrate, Ca(NO3)2.4H2O, calcium nitrate (V)-4-water
Calcium nitrate tetrahydrate, CaN2O6.4H2O
Calcium nitrate hydrated crystals
Calcium nitrate, Norwegian saltpetre, nitrogen fertilizer
Calcium nitrate, Ca(NO3)2, For 0.1 M solution, 16.4 g in 1 L water, Harmful if ingested
Calcium oxalate, Ca(COO)2
Calcium oxalate, CaC2O4, Ca(COO)2, oxalate of lime, needle-shaped crystals, in kidney stones, rhubarb
Raphides, needle-shaped crystals of calcium oxalate monohydrate, usually in mesophyll parenchyma of leaves
Calcium oxide, CaO
Calcium oxide, quicklime, lump, powder, does not occur naturally, Toxic if ingested or by skin contact
Decomposition of oxides: 3.30.5
Heat calcium metal to form calcium oxide: 8.2.14
Heat calcium sulfate, gypsum: 8.4.2
Lime, limewater, limestone
Calcium oxide
Calcium oxide, CaO, lime, quicklime, lump lime, caustic lime, burnt lime, E529, thermoluminescent in oxy-hydrogen flame to cause "limelight".
It is used in agriculture for excess soil acidity, sold in building supplies shops, Toxic if ingested or by skin contact
Calcium oxide does not occur naturally
Calcium phosphate, Ca3(PO4)2
Calcium dihydrogen phosphate (V), Ca(H2PO4)2, monohydrate Ca(H2PO4)2.H2O
Calcium phosphate (V), monocalcium phosphate Ca(H2PO4)2, dicalcium phosphate CaHPO4
Calcium phosphate (V), tricalcium phosphate Ca3(PO4)2, (hydroxyapatite, bone mineral, tooth enamel)
Bone, calcium hydroxyapatite, Ca10(PO4)6(OH)2, + other ions
Calcium hydroxyapatite, Ca5[OH (PO4)3], Ca10(PO4)6(OH)2, similar to bones so bioactive used in surgical implants
Calcium phosphate, calcium phosphate (V) (dibasic), Ca3(PO4)2, Harmful if ingested
Apatite Ca3(PO4)3(OH,F,Cl)
Calcium phosphate, (formerly calcium orthophosphate)
Prepare baking powder, chemical leavening agent, sponging agent: 19.1.9
Calcium phosphate dibasic, HCaO4P
Calcium phosphate tribasic, HCa5O13P3
Calcium phosphate monobasic, monohydrate, H4CaO8P2.H2O
Calcium phosphid, active phoshor, Ca3P2
Calcium pyrophosphate, Ca2O7P2
Calcium phosphate
Calcium phosphate, Ca3O8P2, Ca3(PO4)2, β-calcium phosphate tribasic, β-tricalcium phosphate, tert-calcium phosphate, tri-calcium (ortho)phosphate, calcium phosphate (V), white powder, insoluble, from apatite mineral Ca5(PO4)3(OH,F,Cl), and rock phosphate, from animal bones and teeth (used for fertilizer, facilitates uptake of DNA into cells, "bone ash" for craft), Calcium phosphates (buffer, sequestrant),
formerly "calcium orthophosphate"
Calcium phosphate (V), monocalcium phosphate Ca(H2PO4)2, dicalcium phosphate CaHPO4, tricalcium phosphate Ca3(PO4)2, (hydroxyapatite, bone mineral, tooth enamel)
Calcium phosphate stones, CaHPO.4.2H2O, brushite, a kind of human kidney stone
Calcium sulfate, CaSO4
Calcium sulfate, calcium sulfate (VI), gypsum, Harmful if ingested
Gypsum (calcium sulfate), plaster of Paris: 35.22.6, (Geology)
Tests for gypsum added to the soil: 9.15.5
Plaster of Paris
School chalk, blackboard chalk, safety: 3.71.5
School chalk, blackboard chalk with weak acids: 3.71.7
Solubility of school chalk, blackboard chalk, in water: 3.71.6
Calcium sulfate
Calcium sulfate, CaSO4, gypsum, CaSO4.2H2O, powder, calcium sulfate dihydrate, calcium sulfate (VI), calcium hemihydrate, anhydrite mineral
Calcium sulfate anhydrous, CaSO4, anhydrite mineral, alabaster statues, "snake alabaster" in ore veins
Calcium sulfate, dihydrate, CaSO4.2H2O, gypsum, plaster of Paris, plaster, casting plaster (modroc), grout
Calcium sulfate, hydrated, CaSO4.2H2O, selenite, satin spar, anhydrite, school chalk, blackboard chalk
Calcium sulfate, hydrated, For 0.1 M solution, shake 10 g in 1 L water, leave to stand, decant the clear liquid
Calcium sulfate, hemihydrate, CaSO4.H2O, hemihydrate, plaster of Paris
Calcium sulfate, CaSO4, gypsum, CaSO4.2H2O, powder, calcium sulfate dihydrate, calcium sulfate (VI), calcium hemihydrate, anhydrite mineral
Calcium sulfate occurs as plaster of Paris, CaSO4.
Calcium sulfate occurs in evaporating lakes
Calcium sulfate is used as a stain remover and has anti-inflammatory action in the human body
Alabaster, The term "alabaster" may refer to gypsum, or calcite, called "onyx-marble"
Anhydrite, calcium sulfate anhydrous, CaSO4, "snake alabaster", mineral
Gypsum and bentonite mixtures provide low electrical resistance around anodes and earthing rods
Common names: Plaster of Paris CaSO4.H2O
(The term "alabaster" may refer to gypsum, or calcite, called "onyx-marble".)
Mixtures of gypsum and bentonite provide low electrical resistance around anodes and earthing rods
Carbonates, CO32-
Carbonates, mineral carbonates: 35.19.2, (Geology)
Decomposition of carbonates: 3.30.1
Dilute acids with carbonates, common carbonates: 12.3.9.0
Heat carbonates of Cu, Mg, Na, Pb, Zn: 12.16.3
List of carbonates: 1.11
Prepare carbon dioxide, heat carbonates: 13.7.6
Prepare rayon, basic copper carbonate with ammonia solution: 3.4.8.1
Reactions of carbonates: 12.16.0
Tests for carbonates: 12.11.5.7
Chalk, CaCO3
Chalk, calcium carbonate, rock chalk, French chalk, talcum powder
Chalk (lime) content of the soil, 6.9.02
Chalk, breccia, sedimentary rock, 35.22.3, (Geology)
Chalk: Chalk, (Geology)
Cloud in a bottle: 37.29
Portland cement: 34.66.6
School chalk, blackboard chalk, safety: 3.71.5
School chalk, blackboard chalk with weak acids: 3.71.7
Solubility of school chalk, blackboard chalk, in water 3.71.6
Chalk is a form of limestone, the mineral calcite, from compression of microscopic plankton.
Chalk steep cliffs, e.g. the white cliffs of Dover on the coast of the English Channel.
Blackboard chalk, school chalk, is mainly calcium sulfate
Blackboard chalk used for chromatography
Concrete
Cement
34.66.7 Coade stone
7.4.3.3 Ice melts, de-icers
35.25 Make sedimentary rocks, (Geology)
35.24.2 Make artificial rocks, sedimentary rocks, (Geology)
35.22.4.10 Pozzolana (puteolanum), (Geology)
35.22.4.11 Roman Maritime Concrete Study (ROMACONS), (Geology)
35.2.4.1 Scoria, (Geology)
34.6.3 Strength of paper, shape and its mechanical strength
34.66.3 Tests for concrete alkalinity
34.66.1 Tests for cement brick strength, (contents)
34.66.2 Tests for cement brick strength (water content)
Materials used with concrete
Carving stones include the following: Hebel blocks are autoclaved aerated concrete
Muriatic acid, hydrochloric acid, in hardware shops, about 30% for cleaning or etching concrete
Muriatic acid (25% solution) (in concrete bleach
Titanium dioxide, TiO2, brookite mineral, in self-cleaning concrete
Phosphoric acid for cleaning concrete, Volatile oils: Plant material --> (solvent extraction) --> "concretes" --> "absolutes"
Exothermic reactions, the reactants form products with rise in temperature, Setting of cement and concrete
Metallic corrosion requires at least one metal and an electrolyte, water, soil, concrete or a moist atmosphere
A metal in an electrolyte (water, sea water, soils, concrete) generates an electrical current depending on the type of electrolyte
12.14.5 Superphosphate production.
See 6.42: Artificially-prepared fertilizers.
Superphosphate fertilizer, a mixture of monobasic and dibasic calcium phosphate and calcium sulfate.
It is produced by concentrated sulfuric acid with phosphate rock.
(Ca3(PO4)2 + 2H2SO4).
(Ca(H2PO4)2 + 2CaSO4).
Wear goggles if superphosphate dust is produced.
Dispose of superphosphate in the garbage to landfill.
8.2.14 Heat calcium metal to form calcium oxide
Heat a shaving of calcium metal in a crucible and heat it with a Bunsen
burner for 10-15 minutes, because it is difficult to ignite.
8.4.2 Heat calcium sulfate, gypsum
CaSO4.2H2O + heat --> CaSO4H2O + 1 H2O (steam)
gypsum + heat --> calcium sulfate hemihydrate (plaster of Paris, CaSO4.nH2O).
6.12.1 Calcium deficiency in soils
The plants are small with unusually shaped leaves.
The shoot tips may die.
Chlorosis of young leaves along the veins, in birdsfoot trefoil and blueberry.
Bleaching of upper half leaf, then leaf tip curling, in black pepper and sugarcane.
Growing bud leaf chlorotic white, but leaf base remains green, and distortion of the tips of shoots, i.e. dieback, in peach seedlings.
Brown spots on leaves, reduced expansion and premature leaf senescence, in soybean.
Calcium stress during fruiting increases susceptibility to blossom end rot, in tomato.
Symptoms: bitter pit in apple, leaf tip burn in cabbage and lettuce, black heart of celery, cavity spot of carrots, vitrescence in melons.
Lime applications are used to prevent root rot, depending on the buffering capacity of the soil.