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Similaire à Action of heat on compounds class x.pdf
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Action of heat on compounds class x.pdf
- 1. 1 1. OXIDES Name of the compound Formula Original Colour Final Colour Residue Gas evolved and test Equation 1. Oxides of potassium, sodium, calcium, magnesium, aluminum, zinc, iron and copper do not decompose on heating. 2 Zinc Oxide ZnO White Yellow when hot White when cold Residue turns white on cooling Does not decompose (only changes colour) Eqn : ZnO ZnO (White) (Yellow) 3 Lead Dioxide PbO2 Chocolate brown Yellow Yellow residue fuses with test tube Oxygen Colourless, odourless neutral gas, rekindles a glowing splinter Eqn : 2PbO2 2PbO + O2 4 Red Lead Pb3O4 Red Yellow Yellow residue fuses with the test tube Oxygen Colourless, odourless neutral gas, rekindles a glowing splinter Eqn : 2Pb3O4 6PbO +O2 5 Mercuric Oxide HgO Red Silvery liquid Silvery mirror on sides of test tube Oxygen Colourless, odourless neutral gas, rekindles a
- 2. 2 glowing splinter Eqn : 2HgO 2Hg + O2 6 Silver Oxide Ag2O Greyish black Silver Silver residue at the bottom of the test tube Oxygen Colourless, odourless neutral gas, rekindles a glowing splinter Eqn : 2Ag2O 4Ag + O2 GAS = PRECIPITATE = 2. CARBONATES Name of the compound Formula Original Colour Final Colour Residue Gas evolved test Equation 1 Sodium and Potassium carbonate do not decompose on heating 2 Calcium Carbonate CaCO3 White White White residue of calcium oxide obtained Carbon dioxide Colourless, odourless, slightly acidic to litmus and turns lime water milky Eqn : CaCO3 CaO + CO2 3 Magnesium Carbonate MgCO3 White White White residue of magnesium oxide obtained Carbon dioxide Colourless, odourless, slightly acidic to litmus and turns lime water milky Eqn : MgCO3 MgO + CO2
- 3. 3 4 Zinc Carbonate ZnCO3 White Yellow when hot white when cold Yellow residue of zinc oxide obtained which turns white on cooling Carbon dioxide Colourless, odourless, slightly acidic to litmus and turns lime water milky Eqn : ZnCO3 ZnO + CO2 5 Lead Carbonate PbCO3 White Yellow Yellow residue fuses with the sides of the test tube Carbon dioxide Colourless, odourless, slightly acidic to litmus and turns lime water milky Eqn : PbCO3 PbO + CO2 6 Copper Carbonate CuCO3 Light green Black Black copper oxide formed Carbon dioxide Colourless, odourless, slightly acidic to litmus and turns lime water milky Eqn : CuCO3 CuO + CO2 7 Ammonium carbonate (NH4)2CO3 White No residue Decomposes on exposure to air and leaves no residue Carbon dioxide Colourless, odourless, slightly acidic to litmus and turns lime water milky Ammonia Pungent, smelling, basic gas turns red litmus
- 4. 4 blue and gives dense white fumes with a glass rod of HCl acid Water Vapour Neutral vapours turn Cobalt Chloride paper blue to pink Eqn : (NH4)2CO3 2NH3 + H2O (vap) + CO2 3. BICARBONATES Name of the compound Formula Original Colour Final Colour Residue Gas evolved test Equation 1 Sodium Bicarbonate NaHCO3 White White White solid sodium carbonate Carbon dioxide Colourless, odourless, slightly acidic to litmus and turns lime water milky Water Vapour Neutral vapours turn Cobalt Chloride paper blue to pink Eqn : 2NaHCO3 Na2CO3 + H2O+CO2 2 Potassium Bicarbonate KHCO3 White White White solid potassium carbonate Carbon dioxide Colourless, odourless, slightly acidic to litmus and turns lime water milky Water Vapour Neutral vapours turn Cobalt Chloride paper
- 5. 5 blue to pink Eqn : 2KHCO3 K2CO3 + H2O+CO2 3 Calcium Bicarbonate Ca(HCO3)2 White White White Calcium carbonate residue Carbon dioxide Colourless, odourless, slightly acidic to litmus and turns lime water milky Water Vapour Neutral vapours turn Cobalt Chloride paper blue to pink Eqn : Ca(HCO3) 2 CaCO3 + H2O+CO2 4 Magnesium Bicarbonate Mg(HCO3)2 White White White Magnesium carbonate residue Carbon dioxide Colourless, odourless, slightly acidic to litmus and turns lime water milky Water Vapour Neutral vapours turn Cobalt Chloride paper blue to pink Eqn : Mg(HCO3) 2 MgCO3 + H2O+ CO2 Note: Calcium bicarbonate and Magnesium bicarbonate exists only in solution 4. NITRATES Name of the compound Original Colour Final Colour Residue Gas evolved test
- 6. 6 Formula Equation 1 Sodium Nitrate NaNO3 Colourless Pale yellow liquid Pale yellow liquid Oxygen Colourless, odourless neutral gas, rekindles a glowing splinter Eqn : 2NaNO3 2NaNO2 + O2 2 Potassium Nitrate KNO3 Colourless Pale yellow liquid Pale yellow liquid Oxygen Colourless, odourless neutral gas, rekindles a glowing splinter Eqn : 2KNO3 2KNO2 + O2 3 Calcium Nitrate Ca(NO3)2 Colourless White White residue of calcium oxide Oxygen Colourless, odourless neutral gas, rekindles a glowing splinter Nitrogen dioxide Reddish brown acidic gas Turns Potassium Iodide paper brown in colour Eqn : 2Ca(NO3)2 2CaO + 4NO2 + O2 4 Zinc Nitrate Zn(NO3)2 Colourless Yellow when hot white when cold White residue of Zinc oxide obtained on cooling Oxygen Colourless, odourless neutral gas, rekindles a
- 7. 7 glowing splinter Nitrogen dioxide Reddish brown acidic gas Turns Potassium Iodide paper brown in colour Eqn : 2Zn(NO3)2 2ZnO + 4NO2 + O2 5 Lead Nitrate Pb(NO3)2 White Yellow Yellow residue of lead monoxide fuses with the test tube Oxygen Colourless, odourless neutral gas, rekindles a glowing splinter Nitrogen dioxide Reddish brown acidic gas Turns Potassium Iodide solution brown in colour Eqn : 2Pb(NO3)2 2PbO + 4NO2 + O2 6 Copper Nitrate Cu(NO3)2 Blue Black Black residue of copper oxide Oxygen Colourless, odourless neutral gas, rekindles a glowing splinter Nitrogen dioxide Reddish brown acidic gas Turns Potassium Iodide solution brown in colour Eqn : 2Pb(NO3)2 2PbO + 4NO2 + O2 7 Mercuric Nitrate Hg(NO3)2 Colourless Silvery Silvery residue of mercury on the test tube Oxygen Colourless, odourless neutral gas, rekindles a
- 8. 8 glowing splinter Nitrogen dioxide Reddish brown acidic gas Turns Potassium Iodide paper brown in colour Eqn : Hg(NO3)2 Hg + 2NO2 + O2 8 Silver Nitrate AgNO3 Colourless Silver Silvery residue of silver on the test tube Oxygen Colourless, odourless neutral gas, rekindles a glowing splinter Nitrogen dioxide Reddish brown acidic gas Turns Potassium Iodide paper brown in colour Eqn : 2AgNO3 2Ag + 2NO2 + O2 9 Ammonium Nitrate NH4NO3 White No residue Completely disappears on heating Nitrous Oxide (laughing gas) Water Vapour Neutral vapours turn Cobalt Chloride paper blue to pink Eqn : NH4NO3 2H2O + N2O 5. HYDROUS SALTS Name of the compound Original Final Colour Residue Gas evolved test
- 9. 9 Formula Colour Equation A Hydrated Copper Sulphate CuSO45H2O Blue crystalline compound White anhydrous powder Greyish white residue of copper Sulphate. On strong heating the residue turns black Water vapour Neutral vapours turn Cobalt Chloride paper blue to pink Eqn : CuSO45H2O CuSO4 + 5H2O B Hydrated Sodium Carbonate Na2CO310H2O White crystalline solid White anhydrous powder White anhydrous residue of sodium carbonate Water vapour Neutral vapours turn Cobalt Chloride paper blue to pink Eqn : Na2CO310H2O : Na2CO3 + 10H2O 6. Other compounds a Ammonium dichromate (NH4)2Cr2O7 Orange Decomposes with sparks giving out heat and forms a green fluffy powder Green powder of chromic oxide Water vapour Neutral vapours turn Cobalt Chloride paper blue to pink Nitrogen Colourless neutral gas Eqn : (NH4)2Cr2O7 : Cr2O3 + N2 + 4H2O b Ammonium Chloride NH4Cl White solid Disappears from the bottom of the test tube and settles down as a white solid on the upper cooler parts of the test tube No residue at the bottom of the test tube Ammonia Basic gas turns red litmus blue and gives dense white fumes with a glass rod dipped in HCl Hydrogen Chloride An acidic gas gives dense white fumes with a glass rod dipped in Ammonium Hydroxide Eqn : NH4Cl NH3+ HCl Iodine – Camphor – Naphthalene do not undergo any chemical change when heated, but undergo sublimation Eg: Iodine crystals Iodine vapour
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