Tuesday, February 27, 2007
Random thoughts from chemsics siao liao
Hi everyone. I will be posting randomly. Please bear with me, even if i have mistakes
K>Na>Ca>Mg>C>Zn>H>Fe>Cu>Ag
K reacts in cold water explosively give KOH + H2. Enough heat is produced to cause hydrogen to burn in a lilac flame.
Na reacts very violently in cold water to give NaOH + H2. Hydrogen gas liberated might catch fire.
Ca reacts readily in cold water to give CaOH+H2.
Mg reacts very slowly in cold water. It takes about a week to collect a test tube of hydrogen gas.
Fe, Zn, Ag, Cu do not react in cold water.
Hot Mg reacts very violently in steam to give you MgO and H2 and a bright white glow is produced during the reaction.
Hot Zn burns in steam to give you ZnO + H2. Hot = yellow, Cold = white.
The coke in the blast furnace, C reacts with O2 in the blast furnace to give you carbon dioxide.
Limestone calcium carbonate CaCO3 also decomposes under extreme heat to give you CaO + C02.
Then the carbon dioxide flows up the BF and reacts with more carbon to give you 2CO carbon monoxide. Carbon monoxide then reacts with haematite Fe2O3. Fe203 + 3CO -> 2FE +3CO2.
2Fe flows down in BF in its molten state.
After that CaO + SiO2 -> CaSiO3. Slack is lighter than the iron(l) and floats on top.
Oxidation
increase in oxygen, removal of hydrogen, losing of elections, increase in OS.
Reduction
decrease in O, increase of H, gain electron, decrease OS.
Fe = 0
Fe2+ = +2
FeO-1. x -2 = -1, -2 + 1 = x , x=-1.
Then QA. Cation.
Al3+ reacts with sodium hydroxide solution to give you Al(OH)3 . white ppt. dissolves in excess. white ppt with NH3, insoluble in excess.
Ca2+ reacts with sodium hydroxide solution to give Ca(OH)2. white ppt, insoluble in excess. No reaction with NH3.
Cu2+ reacts with sodium hydroxide solution to give you Cu(OH)2. blue ppt, insoluble in excess. blue ppt, soluble in excess with NH3 and turns dark blue.
Fe2+ reacts with sodium hydroxide solution to give you iron(II)hydroxide. dirty-green ppt produces. turns brown slowly in air, insoluble in excess. dirty-green ppt for NH3,insoluble in excess.
Fe3+ reacts with sodium hydroxide solution to give ~. reddish-brown ppt, insoluble in excess.same with 3
Pb2+ reacts with sodium hydroxide solution to give ~. white ppt, soluble in excess to give colourless solution. For NH3, white ppt, insoluble in ecess.
Zn2+ reacts with sodium hydroxide solution to give ~. white ppt, soluble in excess to give colourless solution, same for NH3.
NH3. no reaction, when burnt, ammonia gas liberated turns damp red litmus blue. no reaction with its same species. too bad.
Anions.
NO3- add dilute sodium hydroxide solution. Add piece of aluminium foil. Warm the mixture, gas liberated turns damp red litmus blue. thus ammonia gas liberated.
CO32-. add dilute hydrochloric acid. pass carbon dioxide through the solution. efferversence is observed. white ppt formed with caCO3. carbon dioxide liberated.
Cl2- add dilute nitric acid. add silver nitrade solution. white ppt observed. silver chloride solution produced. add lead(II)nitrate. white ppt. lead(II)chloride produced.
I- add dilute nitric acid. add silver nitrate solution. yellow ppt, silver iodide formed. add lead(II) nitrate. yellow ppt formed. lead (II) iodide formed.
SO42-. add dilute HCl. add barium chloride solution. barium sulphate solution formed. white ppt.
anyway. potassium (IV) dichromate solution is orange -> green. potassium manganate(VII) purple -> colourless.
to test for Sulphur dioxide (pungent colourless). soak filter paper with acidified potassium (IV) dichromate. turns orange -> green = sulphur dioxide.
H2 gives a pop sound. lighted splint extinguishes.
CO2 , bubble through limewater, white ptt.
Oxygen allows glowing splint to relight.
chlorine (greenish-yellow. pungent). turned blue litmus red.
ammonia turns red litmus blue. pungent colourless.
work done = force x distance.
power = work over time
force = mg for above (x2)'s case.
1/2mv2 massxvelocity 2= kinetic = mgh = gravitational potential energy. mass x 10ms2- x height.
pressure = force over area.
pressure = hpg = height x density x 10ms2-
p1v1=p2v2
sum of anti clockwise = sum of clockwise blabla
stable equlibrium, COG blabla
~omg.
e7ALMIGHTY cheered!12:21 AM
