How does red hematite form...anyone? PLEASE?
964591
It's an iron oxide and it forms in an oxidising environment. Rich deposits may be the result of weathering, or precipitation out of oxygen-rich surface water or oxygen-rich water in hydrothermal veins.\n\nAs to why it is sometimes red and sometimes metallic-grey I'd say it is probably due to the size of the crystals. When it is ground up fine, it is always red. The smaller grains scatter red light.
851188
when a piece of Ag is dropped in FeSO4 sol. no reaction will take place. it is because Ag is less reactive than Fe so it cannot displace Fe in FeSO4
812692
Ferric sulfite, or iron (III) sulfite
502630
The Extraction of Iron \n \n\n\n The solid mixture of haematite ore, coke and limestone is continuously fed into the top of the blast furnace. \nThe coke is ignited at the base and hot air blown in to burn the coke (carbon) to form carbon dioxide in an oxidation reaction (C gains O). \nThe heat energy is needed from this very exothermic reaction to raise the temperature of the blast furnace to over 1000oC to effect the ore reduction. The furnace contents must be he \ncarbon + oxygen ==> carbon dioxide \nC(s) + O2(g) ==> CO2(g) \nat high temperature the carbon dioxide formed, reacts with more coke (carbon) to form carbon monoxide \ncarbon dioxide + carbon ==> carbon monoxide \nCO2(g) + C(s) ==> 2CO(g) \n(note: CO2 reduced by O loss, C is oxidised by O gain) \nThe carbon monoxide is the molecule that actually removes the oxygen from the iron oxide ore. This a reduction reaction (Fe2O3 loses its O, or Fe3+ gains three electrons to form Fe) and the CO is known as the reducing agent (the O remover and gets oxidised in the process). \nThis frees the iron, which is molten at the high blast furnace temperature, and trickles down to the base of the blast furnace. The main reduction reaction is ... \niron(III) oxide + carbon monoxide ==> iron + carbon dioxide \nFe2O3(s) + 3CO(g) ==> 2Fe(l) + 3CO2(g) \nnote, as in the two reactions above, oxidation and reduction always go together! \nOther possible ore reduction reactions are ... \nFe2O3(s) + 3C(g) ==> 2Fe(l) + 3CO(g) \n2Fe2O3(s) + 3C(g) ==> 4Fe(l) + 3CO2(g) \nThe original ore contains acidic mineral impurities such as silica (SiO2, silicon dioxide). These react with the calcium carbonate (limestone) to form a molten slag of e.g. calcium silicate. \ncalcium carbonate + silica ==> calcium silicate + carbon dioxide \nCaCO3 + SiO2 ==> CaSiO3 + CO2 \nthis is sometimes shown in two stages: \nCaCO3 ==> CaO + CO2 \nCaO + SiO2 ==> CaSiO3 \nThe molten slag forms a layer above the more dense molten iron and they can be both separately, and regularly, drained away. The iron is cooled and cast into pig iron ingots OR transferred directly to a steel producing furnace. \nIron from a blast furnace is ok for very hard cast iron objects BUT is too brittle for many applications due to too high a carbon content from the coke. So it is converted into steel alloys for a wide range of uses. \nThe waste slag is used for road construction or filling in quarries which can then be landscaped. \n \n\n\nThe Extraction of Aluminium \n \n\n\n The purified bauxite ore of aluminium oxide is continuously fed in. Cryolite is added to lower the melting point and dissolve the ore. \nIons must be free to move to the electrode connections called the cathode (-, negative), attracting positive ions e.g. Al3+, and the anode (+, positive) which attracts negative ions e.g. O2-. \nWhen the d.c. current is passed through aluminium forms at the negative cathode (metal*) and sinks to the bottom of the tank. \nAt the positive anode, oxygen gas is formed (non-metal*). This is quite a problem. At the high temperature of the electrolysis cell it burns and oxidises away the carbon electrodes to form toxic carbon monoxide or carbon dioxide. So the electrode is regularly replaced and the waste gases dealt with!  \nIt is a costly process (6x more than Fe!) due to the large quantities of expensive electrical energy needed for the process. \n* Two general rules: \nMetals and hydrogen (from positive ions), form at the negative cathode electrode. \nNon-metals (from negative ions), form at the positive anode electrode. \n\n\nThe original extraction of copper from copper ores\n \nfrom copper carbonate ores* ... \nThe ore can be roasted to concentrate the copper as its oxide. \nWater is driven off and the carbonate thermally decomposed. \ncopper(II) carbonate ==> copper oxide + carbon dioxide \nCuCO3(s) ==> CuO(s) + CO2(g) \nThe oxide can be smelted by heating with carbon (coke, charcoal) to reduce the oxid
946990
FeCl3 + NaCl -> FeCl2 + NaCl3\n\n\nFeCl3 + NaCl -> FeCl2 + NaCl3\n\nthese reactions are not possible \nas this reaction can take place if iron(fe) was more reactive than sodium or fe was less electropositive than na\nhence \nthese reactions are not possible
1125539
343.2 g of Fe2O3 - take the molar mass of Fe2O3. 2 irons is 55.85 * 2 = 111.70 grams per mole. 3 oxygens is 16 * 3 = 48. Divide 343.2 g by 159.70 g/mol and you get 2.15 moles.\n\nYour original reaction uses 2 moles of ferric oxide, so you need to multiply everything by (2.15 / 2) to get your ferric oxide to say 2.15 moles. When you do this, you will change your Kcal value to the right number.\n\n2 Fe2O3 (s) + 196.5 Kcal --> 4 Fe(s) + 3 O2 (g)\n2.15 Fe2O3 (s) + 211.2 Kcal --> 4.30 Fe(s) + 3.23 O2 (g)\n\nNote that I really didn't care about significant figures, so you should probably make sure I didn't round off incorrectly. The 2 and 4 and 3 in the equation are exact (2.0000....), but the 196.5 is an inexact number.\n\nThe second equation is easier, because you already have 0.393 in moles. You need to multiply by something that turns a 2 C3H6O into 0.393 C3H6O. So that's simply (0.393 / 2).\n2 C3H6O + 8 O2(g) --> 6 CO2 (g) + 6 H2O(g) + 853.6 kcal \n0.393 C3H6O + 1.572 O2(g) --> 1.179 CO2 (g) + 1.179 H2O(g) + 167.7324 kcal\n\nSo basically, you need to find some known number of moles, and multiply and divide your balanced equation until it has that number of moles in the equation. Then you read off whatever you need.
37650
Yes.\n\nOrthoclase feldspar is an example.  At high temperatures, Fe will fit into the orthoclase lattice.  As temperature drops, the lattice shrinks so that Fe no longer fits.  Fe diffuses out of the latice and accumulates along the planes between orthoclase crystal twins.  Along the way, it grabs O to produce Fe2O3.  If you look closely at pink granite, usually you will see that the pink grains are actually white and red striped.  Those grains are orthoclase crystals with exsolved hematite along twin planes.\n\nExsolution and diffusion of Fe from orthoclase can only occur at high temperature.  If the orthoclase cools too quickly for the Fe to diffuse out, it will remain in the orthoclase lattice, which will be distorted to accomodate the larger (larger than K) Fe ion.\n\nMaterial science is not boring.
727004
(NH4)2Cr2O7 -> Cr2O3 + 4*(H2O) + N2\n\n(NH4)2SO4 + 2*(NaOH) -> 2*(NH3) + 2*(H2O) + Na2SO4\n\nFe2(SO4)3 + 6*(NH3) + 6*(H2O) -> 2*(Fe(OH)3) + 3*((NH4)2SO4)
975287
crystallization from magma !!! like feldspar , quartz , olivine , pyroxene ...\n\nprecipitation from a solution !!! like calcite , halite , hematite, gypsum .. \n\nsome minerals form in the two ways .. like quartz which may crystallize from a magma as in granite or precipitate from Si rich solutions as in some sedimentary rocks when it fills the bores ..
858632
Typically rocks with a reddish color have a high content of iron.  The color is essentially iron oxide (rust).
437636
The mineral composition of the soil affects whether the it will be red or light colored. We have a lot of clay in NC - orange & red indicates that iron is present. The parent material from which the soil came from has a lot to do with determining the mineral content.\n\nBeach sands can be all different colors because of their parent material. Black sand beaches of Hawaii came from basaltic lava parent material.\n\nOrganic matter can also cause soils to be different colors. Usually the darker the soil the more organic matter.
145630
The answer is actually quite interesting. The iron in a group called the Heme ring of Hemoglobin is oxidized by oxygen but not O as you would think. It's oxidized by elemental oxygen 02. The iron is not free. It is contained within a heme ring and it cannot be converted to free rust because it's actually contained within another structure. If the iron were to be freed then that might happen but free elemental iron in the blood is toxic I believe. Iron supplements do not have that occur though. If in need your body readily uses it but if you have iron in excess then it might be possible.
408981
For iron to become iron oxide, three things are required: iron, water and oxygen. Here's what happens when the three get together:\nWhen a drop of water hits an iron object, two things begin to happen almost immediately. First, the water, a good electrolyte, combines with carbon dioxide in the air to form a weak carbonic acid. As the acid is formed the iron dissolves.  Some of the water will begin to break down into its component pieces -- hydrogen and oxygen. The free oxygen and dissolved iron bond into iron oxide, in the process freeing electrons. The electrons liberated from the anode portion of the iron flow to the cathode, which may be a piece of a metal less electrically reactive than iron, or another point on the piece of iron itself.\nThe chemical compounds found in liquids like acid rain and seawater make them better electrolytes than pure water, thus they speed the process of rusting on iron.
764128
The soil is very iron-rich. When iron oxidizes, it produces iron oxide which is basically rust and it red in color. :)\n\nAnd interesting side fact, the dawn and dusk sky is blue. (It's reddish on Earth :)
487534
It is possible to grow crystals that are naturally red.  You grow them from potassium ferricyanide (not the same as cyanide).  \n\nThese links have more information about red crystals.  I hope this helps.
537646
The thing is that iron III hydroxide isn't soluble in water.  It just sits there and doesn't make many hydroxide ions, which are necessary for a strongly basic solution.  Barium hydroxide, however, is soluble and breaks up into barium ions and hydroxide ions, giving a strongly basic solution.
1163963
Do you mean the molecular composition or macroscopic composition? There would be too much to post here so I suggest you visit the following\n\nhttp://users.rcn.com/jkimball.ma.ultranet/BiologyPages/B/Blood.html#formation