In decomposition reaction, a single reactant breaks down into two or more simpler product, while in combination reaction two or more reactant combine to form a single product. Therefore decomposition and combination reaction are opposite. Example of decomposition : (i) 2FeSO4(s) Read more
In decomposition reaction, a single reactant breaks down into two or more simpler product, while in combination reaction two or more reactant combine to form a single product. Therefore decomposition and combination reaction are opposite.
Decompositive reaction in presence of Heat: 2Pb(NO3)2 (s) -- Heat → 2PbO (s) + 4NO2(g) + O2(g) Lead Nitrate Leadoxide Nitrogen dioxide Oxygen Decompositive reaction in presence of Light: 2AgCl - Light→ Read more
Decompositive reaction in presence of Heat:
2Pb(NO3)2 (s) — Heat → 2PbO (s) + 4NO2(g) + O2(g)
Lead Nitrate Leadoxide Nitrogen dioxide Oxygen
Decompositive reaction in presence of Light:
2AgCl – Light→ 2Ag + Cl2 gas
Silver Chloride (white) (grey)
Decompositive reaction by the use of electricity:
Displacement Reaction : In this reaction more reactive element displaces the less reactive element AB + C → AC + B eg.: (i) Fe + CuSO4 → FeSO4 + Cu (ii) Pb + CuCl2 → PbCl2 + Cu Double Displacement Reaction : In this reaction exchange of ions takes place AB Read more
Displacement Reaction : In this reaction more reactive element displaces the less reactive element
AB + C → AC + B
eg.:
(i) Fe + CuSO4 → FeSO4 + Cu
(ii) Pb + CuCl2 → PbCl2 + Cu
Double Displacement Reaction : In this reaction exchange of ions takes place
In a chemical reaction a insoluble substance (precipitate) is formed is called precipitation reaction. eg.: (i) AgNO3 + NaCl → AgCl + NaNO3 Silver Sodium Silver Sodium nitrate Chloride Chloride nitrate (ii) NaRead more
In a chemical reaction a insoluble substance (precipitate) is formed is called precipitation reaction.
(a) Oxidation: Reaction in which a substance gains oxygen or addition of oxygen or removal of hydrogen in a reaction is called oxidation. Eg.: (i) 2Cu + O2 → 2CuO (ii) 4Al + 3O2 → 2Al2O3 (b) Reduction: Reaction in which a substance looses oxygen or removal of oxygen or gain of hydrogeRead more
(a) Oxidation: Reaction in which a substance gains oxygen or addition of oxygen or removal of hydrogen in a reaction is called oxidation.
Eg.:
(i) 2Cu + O2 → 2CuO
(ii) 4Al + 3O2 → 2Al2O3
(b) Reduction: Reaction in which a substance looses oxygen or removal of oxygen or gain of hydrogen in a reaction is called reduction.HEg.:
(i) CuO + H2 → Cu + H2O
oxygen is removed from copper oxide so reduction of CuO occurs.
(ii) H2S + Cl2 → 2HCl + S
gain of hydrogen by chlorine gas, so chlorine is reducted to form HCl.
The brown coloured element 'X' is copper. On heating in air it forms copper oxide which is black in colour. 2Cu(s) + O2(g) → 2CuO(s) Copper Oxygen Copper oxide (Brown (Black) color)
The brown coloured element ‘X’ is copper. On heating in air it forms copper oxide which is black in colour.
Iron articles is painted to prevent from rusting, so that iron article is do not come in contact with atmosphere oxygen and moisture. This will prevented it from rusting.
Iron articles is painted to prevent from rusting, so that iron article is do not come in contact with atmosphere oxygen and moisture. This will prevented it from rusting.
As nitrogen is inert gas it doesnot react with oil and fat. Nitrogen gas prevent oil and fat containing food items from rancidity. Food items get rancid means it smells and tastes bad due to oxidation with the atmosphere oxygen.
As nitrogen is inert gas it doesnot react with oil and fat. Nitrogen gas prevent oil and fat containing food items from rancidity. Food items get rancid means it smells and tastes bad due to oxidation with the atmosphere oxygen.
Corrosion: Metal are reacted with atmosphere oxygen, carbon dioxide and moisture and converted into metal oxides and carbonate. This phenomenon is called corrosion. Eg.: (i) Black coating on silver. 4Ag + 2H2S + O2 -----------> 2Ag2S + 2H2O (ii) Green coating on copper. Cu + CO2 + H2O -------Read more
Corrosion: Metal are reacted with atmosphere oxygen, carbon dioxide and moisture and converted into metal oxides and carbonate. This phenomenon is called corrosion.
Eg.:
(i) Black coating on silver.
4Ag + 2H2S + O2 ———–> 2Ag2S + 2H2O
(ii) Green coating on copper.
Cu + CO2 + H2O ———–> CuCO3. Cu (OH)2
(b) Rancidity: Oil and fat containing items when comes in contact with atmosphere oxygen they get oxidised and start smelling and tasting bad. The food item have gone rancid. This phenomeon is called rancidity.
Eg.:
(i) Smell and taste on food items get change after some times.
Why are decomposition reactions called the opposite of combination reactions? Write equations for these reactions.
In decomposition reaction, a single reactant breaks down into two or more simpler product, while in combination reaction two or more reactant combine to form a single product. Therefore decomposition and combination reaction are opposite. Example of decomposition : (i) 2FeSO4(s) Read more
In decomposition reaction, a single reactant breaks down into two or more simpler product, while in combination reaction two or more reactant combine to form a single product. Therefore decomposition and combination reaction are opposite.
Example of decomposition :
(i) 2FeSO4(s) —Heat→ Fe2O3(s) + SO2(g) + SO3(g)
Ferrous sulphate Ferric oxide
(ii) CaCO3(s) —Heat→ CaO(s) + Co2(g)
Lime stone Quick lime
Example of combination :
(i) CaO(s) + CO2(g) → CaCO3(s)
Quick lime Carbon dioxide Lime stone
(ii) Burning of coal →
C(s) + O2(g) → CO2(g)
See lessWrite one equation each for decomposition reactions where energy is supplied in the form of heat, light or electricity.
Decompositive reaction in presence of Heat: 2Pb(NO3)2 (s) -- Heat → 2PbO (s) + 4NO2(g) + O2(g) Lead Nitrate Leadoxide Nitrogen dioxide Oxygen Decompositive reaction in presence of Light: 2AgCl - Light→ Read more
Decompositive reaction in presence of Heat:
2Pb(NO3)2 (s) — Heat → 2PbO (s) + 4NO2(g) + O2(g)
Lead Nitrate Leadoxide Nitrogen dioxide Oxygen
Decompositive reaction in presence of Light:
2AgCl – Light→ 2Ag + Cl2 gas
Silver Chloride (white) (grey)
Decompositive reaction by the use of electricity:
2H2O (l) — Electricity→ 2H2 (g) + O2 (g)
water hydrogen gas oxygen gas
See lessWhat is the difference between displacement and double displacement reactions? Write equations for these reactions.
Displacement Reaction : In this reaction more reactive element displaces the less reactive element AB + C → AC + B eg.: (i) Fe + CuSO4 → FeSO4 + Cu (ii) Pb + CuCl2 → PbCl2 + Cu Double Displacement Reaction : In this reaction exchange of ions takes place AB Read more
Displacement Reaction : In this reaction more reactive element displaces the less reactive element
AB + C → AC + B
eg.:
(i) Fe + CuSO4 → FeSO4 + Cu
(ii) Pb + CuCl2 → PbCl2 + Cu
Double Displacement Reaction : In this reaction exchange of ions takes place
AB + CD → AC + BD
eg.:
(i) Na2SO4 + BaCl2 → 2NaCl + BaSO4
See less(ii) HCl + AgNO3 → AgCl + HNO3
In the refining of silver, the recovery of silver from silver nitrate solution involved displacement by copper metal. Write down the reaction involved.
Reaction occurs as: 2AgNO3 + Cu → Cu(NO3)2 + 2Ag Silver Copper Copper Silver nitrate nitrate
Reaction occurs as:
2AgNO3 + Cu → Cu(NO3)2 + 2Ag
See lessSilver Copper Copper Silver
nitrate nitrate
What do you mean by a precipitation reaction? Explain by giving examples.
In a chemical reaction a insoluble substance (precipitate) is formed is called precipitation reaction. eg.: (i) AgNO3 + NaCl → AgCl + NaNO3 Silver Sodium Silver Sodium nitrate Chloride Chloride nitrate (ii) NaRead more
In a chemical reaction a insoluble substance (precipitate) is formed is called precipitation reaction.
eg.:
(i) AgNO3 + NaCl → AgCl + NaNO3
Silver Sodium Silver Sodium
nitrate Chloride Chloride nitrate
(ii) Na2SO4 + BaCl2 → BaSO4 + 2NaCl
See lessSodium Barium Barium Sodium
Sulphate Chloride Sulphate Chloride
(ppt)
Explain the following in terms of gain or loss of oxygen with two examples each.
(a) Oxidation: Reaction in which a substance gains oxygen or addition of oxygen or removal of hydrogen in a reaction is called oxidation. Eg.: (i) 2Cu + O2 → 2CuO (ii) 4Al + 3O2 → 2Al2O3 (b) Reduction: Reaction in which a substance looses oxygen or removal of oxygen or gain of hydrogeRead more
(a) Oxidation: Reaction in which a substance gains oxygen or addition of oxygen or removal of hydrogen in a reaction is called oxidation.
Eg.:
(i) 2Cu + O2 → 2CuO
(ii) 4Al + 3O2 → 2Al2O3
(b) Reduction: Reaction in which a substance looses oxygen or removal of oxygen or gain of hydrogen in a reaction is called reduction.HEg.:
(i) CuO + H2 → Cu + H2O
oxygen is removed from copper oxide so reduction of CuO occurs.
(ii) H2S + Cl2 → 2HCl + S
See lessgain of hydrogen by chlorine gas, so chlorine is reducted to form HCl.
A shiny brown coloured element ‘X’ on heating in air becomes black in colour. Name the element ‘X’ and the black coloured compound formed.
The brown coloured element 'X' is copper. On heating in air it forms copper oxide which is black in colour. 2Cu(s) + O2(g) → 2CuO(s) Copper Oxygen Copper oxide (Brown (Black) color)
The brown coloured element ‘X’ is copper. On heating in air it forms copper oxide which is black in colour.
2Cu(s) + O2(g) → 2CuO(s)
See lessCopper Oxygen Copper oxide
(Brown (Black)
color)
Why do we apply paint on iron articles?
Iron articles is painted to prevent from rusting, so that iron article is do not come in contact with atmosphere oxygen and moisture. This will prevented it from rusting.
Iron articles is painted to prevent from rusting, so that iron article is do not come in contact with atmosphere oxygen and moisture. This will prevented it from rusting.
See lessOil and fat containing food items are flushed with nitrogen. Why?
As nitrogen is inert gas it doesnot react with oil and fat. Nitrogen gas prevent oil and fat containing food items from rancidity. Food items get rancid means it smells and tastes bad due to oxidation with the atmosphere oxygen.
As nitrogen is inert gas it doesnot react with oil and fat. Nitrogen gas prevent oil and fat containing food items from rancidity. Food items get rancid means it smells and tastes bad due to oxidation with the atmosphere oxygen.
See lessExplain the following terms with one example each.
Corrosion: Metal are reacted with atmosphere oxygen, carbon dioxide and moisture and converted into metal oxides and carbonate. This phenomenon is called corrosion. Eg.: (i) Black coating on silver. 4Ag + 2H2S + O2 -----------> 2Ag2S + 2H2O (ii) Green coating on copper. Cu + CO2 + H2O -------Read more
Corrosion: Metal are reacted with atmosphere oxygen, carbon dioxide and moisture and converted into metal oxides and carbonate. This phenomenon is called corrosion.
Eg.:
(i) Black coating on silver.
4Ag + 2H2S + O2 ———–> 2Ag2S + 2H2O
(ii) Green coating on copper.
Cu + CO2 + H2O ———–> CuCO3. Cu (OH)2
(b) Rancidity: Oil and fat containing items when comes in contact with atmosphere oxygen they get oxidised and start smelling and tasting bad. The food item have gone rancid. This phenomeon is called rancidity.
Eg.:
(i) Smell and taste on food items get change after some times.
See less