action of heat on chemical compound e book

ACTION OF HEAT ON CHEMICAL COMPOUNDS

“Analytical chemistry -I”

DE’S FOUNDATIONBISTUPUR, JSR

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metal oxide“Oxides of metals are generally stable to heat and

they are considered to be most stable form of compound found in nature.”

Oxides of potassium,sodium,calcium,magnesium,aluminum , zinc,iron,lead and copper are stable to heat

CuOZnOPbO




2HgO 2Hg + O2

MERCURIC OXIDE“Mercury(II)oxide”

“orange red”

1.The amorphous powder changes to dark red and appears almost black.2.It gives off a colourless, odourless gas which relights a glowing wooden splint3. A silvery mirror like surface is formed near the mouth of the test tube. On scratching the surface ,it forms tiny droplets of mercury4.Gaseous product -oxygen and residue-Mercury




SILVER(I)OXIDE

2Ag2O 4Ag + O2

1.The amorphous greyish powder on heating leaves behind residue which is silver 2.It gives off a colourless, odourless gas which relights a glowing wooden splint




“action of heat on higher oxide of metal”

LEAD DIOXIDE

2PbO2 2PbO + O2

1.The amorphous powder changes to yellow powder 2.It gives off a colourless,odourless gas,which relights the glowing wooden splinter 3.The residue on cooling fuses with the glass and stains the test tube yellowDeduction- gaseous product -Oxygen residue- Lead(II)oxide --->




TRI LEAD TETRA OXIDE

2Pb3O4 6PbO + O2

1.The amorphous powder changes to yellow colour.2.It gives colourless odourless gas, which relights glowing wooden splint. 3.The residue on cooling partly fuses with the glass and stains the test tube yellow.4.Deduction- gaseous product - oxygen residue- lead(II)oxide




carbonates”

CO32-

“action of heat on

CALCIUM CARBONATE

MAGNESIUM CARBONATE

ZINC CARBONATE

LEAD(II)CARBONATE

COPPER(II)CARBONATE

AMMONIUMCARBONATEhttp://foricseandbeyond.blogspot.in/











CALCIUM CARBONATE

CaCO3 CaO + CO2

1. Calcium carbonate on heating leaves behind white residue2.A colourless and odourless gas is evolved which turns lime water milky. It has no effect on K2Cr2O7 solution or KMnO4 solution, also extinguishes burning wooden splint3.Deduction- gas- carbondioxide white solid- calcium oxide




MAGNESIUM CARBONATE

MgCO3 MgO + CO2

1. Magnesium carbonate when heated leaves behind white residue on magnesium oxide2.A colourless and odourless gas is evolved which turns lime water milky. It has no effect on K2Cr2O7 solution or KMnO4 solution, also extinguishes burning wooden splint3.deduction - gas- carbon dioxide white residue- magnesium oxide




ZINC CARBONATE

1. The light amorphous solid on strong heating changes to pale yellow colour .2. It gives off a colourless and odourless gas, which extinguishes burning wooden splint and turns lime water milky but has no effect on K2Cr2O7 solution or KMnO4

solution.3.the residue on cooling changes to white colour

ZnCO3 ZnO + CO2




LEAD(II)CARBONATE

PbCO3 PbO + CO2

1. The white amorphous powder changes to yellow colour.2.A colourless and odourless gas is evolved which turns lime water milky. It has no effect on K2Cr2O7 solution or KMnO4 solution, also extinguishes burning wooden splint.3.The residue on cooling partly fuses with the glass and stains the test tube yellow.4.Deduction- gas- carbon dioxide residue- lead(II)oxide also called litharge or lead monoxide http://foricseandbeyond.blogspot.in/



COPPER(II)CARBONATE

1. The light green amorphous powder changes to black colour on strong heating. 2.A colourless and odourless gas is evolved which turns lime water milky. It has no effect on K2Cr2O7 solution or KMnO4 solution, also extinguishes burning wooden splint.3.The residue on cooling partly fuses with the glass and stains the test tube yellow.4.Deduction- gas- carbon dioxide residue-Copper(II)oxide

CuCO3(s) CuO + CO2(g)

AMMONIUMCARBONATE

(NH4)2CO3(s) NH3(g) + H2O(g) + CO2(g)

1. The colourless compound on exposure to atmosphere decompose to give ammonia ,water and carbon dioxide.




“action of heat on Bicarbonates”

1. Bicarbonates when heated get decomposed to form respective carbonate, water and carbon-dioxide

NaHCO3(s) Na2CO3(s) + H2O(g) + CO2(g)

KHCO3(s) K2CO3(s) + H2O(g) + CO2(g)

Ca(HCO3)2(aq) CaCO3(s) + H2O(g) + CO2(g)

Mg(HCO3)2(aq) MgCO3(s) + H2O(g)+ CO2(g)

“action of heat on

nitratesPOTASSIUM NITRATESODIUM NITRATE

CALCIUM NITRATEZINC NITRATE HEXA HYDRATE

ZINC NITRATELEAD(II) NITRATE

COPPER(II)NITRATEMERCURY(II)NITRATESILVER NITRATEhttp://foricseandbeyond.blogspot.in/



KNO3(s) KNO2(s) + O2(g)

POTASSIUM NITRATE

NaNO3(s) NaNO2(s) + O2(g)

SODIUM NITRATE

Nitrates of potassium and sodium slowly decompose to form metal nitrite and oxygen gas




CALCIUM NITRATE

Ca(NO3)2(s) CaO(s) + NO2 (g) + O2(g)

1. The colourless compound on heating leaves behind white residue and reddish brown gas which turns moist blue litmus red and potassium iodide paper brown, also liberates oxygen which relight the glowing wooden splint.




ZINC NITRATE HEXA HYDRATE

1. It is a white crystalline solid which has a tendency to get wet in air. i.e It is deliquescent in nature. 2.On strong heating it melts to form white sticky mass which gives off vapour,these vapours condenses on the cooler part of the test tube to form t iny drop lets o f the co lour less liquids ,which turns anhydrous copper sulphate blue and cobalt chloride pink.

Zn(NO3)2.6H2O(s) Zn(NO3) + H2O




ZINC NITRATE

yellow when hot white when cold

2Zn(NO3)2.(s) 2ZnO(s) + 4NO2(g) + O2(g)

1.On heating more strongly the white residue gives off reddish brown fumes which turns moist blue litmus paper red, and starch iodide paper blue.2.A glowing wooden splint held in the reddish brown gas burst into flame, thus with reddish brown gas oxygen is mixed.3.The residue left in the test tube is pale yellow when hot .However, on cooling it changes to white colour.




2Pb(NO3)2.(s) 2PbO(s) + 4NO2(g) + O2(g)

LEAD(II) NITRATE

1.The heavy,crystalline solid on heating crumbles with crackling noise.2.It gives off reddish brown gas,which turns moist blue litmus paper red and moist starch iodide paper blue.3.when a glowing wooden splint is held in the reddish brown gas ,it relights.4.the residue is reddish brown when hot and yellow when cold ,partly fuse with glass and stains it yellow5.Deduction- gas - Nitrogen dioxide and oxygen residue- Lead(II)oxide

2Cu(NO3)2.(s) 2CuO(s) + 4NO2(g) + O2(g)

COPPER(II)NITRATE

1.The bluish green mass on heating changes to black residue.2.It gives off reddish brown gas,which turns moist blue litmus paper red and moist starch iodide paper blue.3.when a glowing wooden splint is held in the reddish brown gas ,it relights.4.the residue is reddish brown when hot and yellow when cold ,partly fuse with glass and stains it yellow5.Deduction- gas - Nitrogen dioxide and oxygen residue- Copper(II)oxide.

2Hg(NO3)2.(s) Hg(s) + 2NO2(g) + O2(g)

MERCURY(II)NITRATE

SILVER NITRATE2AgNO3.(s) 2Ag(s) + 2NO2(g) + O2(g)

Both nitrate of mercur y and silver, decomposes to give respective metal ,as the oxide of these metals are thermally unstablewith the evolution of reddish brown gas of nitrogen dioxide and clourless gas oxygen




“action of heat on some other chemical compound”

Ammonium nitrateNH4NO3(g) N2O(g) + H2O(g)

“it decomposes to give nitrous oxide and water vapour N2O is called laughing gas,also used as anesthesia.”

Ammonium ChlorideNH4Cl(s) NH3(g)+ HCl(g)

“White crystalline solid on strong heating sublimes to form dense white fumes, the dense white fume form white powdery mass on cooler part of the test-tube”




Ammonium Dichromate

(NH4)2Cr2O7(s) Cr2O3(g) + N2 + 4H2O(g)

1.“The orange crystalline solid on strong heating swells up many times its volume and gives off steamy fumes,which condenses on the cooler part of test-tube to form tiny droplets of colourless liquid.2.The colourless liquid turns cobalt chloride paper pink 3.A colouless and odourless gas is given out which neither is combustable nor does it support combustion. It does not turn lime water milky4.the residue is green, Cr2O3

Cr2O3




Copper(II)Sulphate PentaHydrate

CuSO4.5H2O(s) CuSO4(s) + 5H2O(g)

CuSO4(s) 2CuO(s) + 2SO2(g) + O2(g)

1.“The Blue crystalline solid on heating crumbles to form white amorphous powder 2.It gives off steamy vapours which condense on the cooler part of the test tube to form tiny droplets of colouless liquid.3.the colourless liquid turns blue cobalt chloride paper pink.The salt is hydrated salt4.on strong heating sulphur dioxide and oxygen are given and a black residue is left in the test tube.http://foricseandbeyond.blogspot.in/




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action of heat on chemical compound e book

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