Exothermic reaction – A reaction in which heat is released is called the exothermic reaction. Burning of fuel is an example of exothermic reaction. When methane is burnt it gives heat along with carbon dioxide and water. CH4(g) + O2(g) → CO2(g) + H2O(l) + Heat Endothermic reaction – ARead more
Exothermic reaction – A reaction in which heat is released is called the exothermic reaction. Burning of fuel is an example of exothermic reaction. When methane is burnt it gives heat along with carbon dioxide and water.
CH4(g) + O2(g) → CO2(g) + H2O(l) + Heat
Endothermic reaction – A reaction in which heat is absorbed is called endothermic reaction. Example – When silver chloride is left in the sunlight, it absorbs heat and turns grey because of formation of silver metal.
In the course of respiration glucose is broken into carbon dioxide and energy is released. That’s why it is considered as an exothermic reaction. C6H12O6(aq)+6O2→6CO2(aq)+6H2O(I)+Energy
In the course of respiration glucose is broken into carbon dioxide and energy is released. That’s why it is considered as an exothermic reaction. C6H12O6(aq)+6O2→6CO2(aq)+6H2O(I)+Energy
In a combination reaction two or more substances are combined to form new substance while in the decomposition reaction one substance decomposes into two or more substances. Hence, the decomposition reactions are called opposite of combination reactions. Example of decomposition : (i) 2FeSO4(s) Read more
In a combination reaction two or more substances are combined to form new substance while in the decomposition reaction one substance decomposes into two or more substances. Hence, the decomposition reactions are called opposite of combination reactions.
When a more reactive element displaces a less reactive element from its salt solution, then it is called displacement reaction. While there is an exchange of ions between the reactants to produce new substances, it is called double displacement reaction. In displacement reaction one displacement takRead more
When a more reactive element displaces a less reactive element from its salt solution, then it is called displacement reaction. While there is an exchange of ions between the reactants to produce new substances, it is called double displacement reaction. In displacement reaction one displacement takes place. While in double displacement reaction two displacements takes place.
Displacement reaction Mg(s)+2HCl(aq)→MgCl2+H2(g)
Reactions in which precipitate is formed are called precipitation reactions. Generally in a precipitation reaction insoluble salts are settled down as precipitate. Na2SO4(aq)+BaCl2(aq)→BaSO4s+2NaCl(aq) In the above reaction, when sodium sulphate reacts with barium chloride, the white precipitate ofRead more
Reactions in which precipitate is formed are called precipitation reactions. Generally in a precipitation reaction insoluble salts are settled down as precipitate. Na2SO4(aq)+BaCl2(aq)→BaSO4s+2NaCl(aq)
In the above reaction, when sodium sulphate reacts with barium chloride, the white precipitate of barium sulphate is formed along with the sodium chloride.
Oxidation - When a substance gains oxygen or loses hydrogen during a reaction, it is called that the substance is oxidized. This phenomenon is called oxidation. 2Cu + O2 --> 2CuO In this reaction copper gains oxygen and hence is oxidized. CuO + H2 --> Cu + H2O In the above reaction hydroRead more
Oxidation – When a substance gains oxygen or loses hydrogen during a reaction, it is called that the substance is oxidized. This phenomenon is called oxidation.
2Cu + O2 –> 2CuO
In this reaction copper gains oxygen and hence is oxidized.
CuO + H2 –> Cu + H2O
In the above reaction hydrogen gains oxygen, and hence oxidized.
Reduction – If a substance loses oxygen or gains hydrogen during a reaction, it is that the substance is reduced. This phenomenon is called reduction.
ZnO + C → Zn + CO
In this reaction zinc loses oxygen, and hence called is reduced. MnO2+4HCl→MnCl2+2H2O+Cl2
In this reaction Mangnese dioxide loses oxygen and hence is called reduced.
Copper is a brown coloured shiny element, when heated in air, it becomes black in colour. 2Cu+O2→2CuO Hence, the element ‘X’ is copper and black coloured compound formed is copper oxide.
Copper is a brown coloured shiny element, when heated in air, it becomes black in colour. 2Cu+O2→2CuO
Hence, the element ‘X’ is copper and black coloured compound formed is copper oxide.
When articles made of iron come in contact with the moisture present in air, it forms iron oxide, which is known as rust. Hence, to prevent an iron article to come in contact with moisture present in air paint is applied. Paint prevents the iron to get rusted.
When articles made of iron come in contact with the moisture present in air, it forms iron oxide, which is known as rust. Hence, to prevent an iron article to come in contact with moisture present in air paint is applied. Paint prevents the iron to get rusted.
When fats and oils are oxidised, they become rancid and their smell and taste change. Hence, food items containing oil and fat are flushed with nitrogen which prevents them to get oxidized and becoming rancid.
When fats and oils are oxidised, they become rancid and their smell and taste change. Hence, food items containing oil and fat are flushed with nitrogen which prevents them to get oxidized and becoming rancid.
What does one mean by exothermic and endothermic reactions? Give examples.
Exothermic reaction – A reaction in which heat is released is called the exothermic reaction. Burning of fuel is an example of exothermic reaction. When methane is burnt it gives heat along with carbon dioxide and water. CH4(g) + O2(g) → CO2(g) + H2O(l) + Heat Endothermic reaction – ARead more
Exothermic reaction – A reaction in which heat is released is called the exothermic reaction. Burning of fuel is an example of exothermic reaction. When methane is burnt it gives heat along with carbon dioxide and water.
CH4(g) + O2(g) → CO2(g) + H2O(l) + Heat
Endothermic reaction – A reaction in which heat is absorbed is called endothermic reaction. Example – When silver chloride is left in the sunlight, it absorbs heat and turns grey because of formation of silver metal.
2AgCl(s) Sunlight → 2Ag(s)+Cl₂(g)
See lessWhy is respiration considered an exothermic reaction? Explain.
In the course of respiration glucose is broken into carbon dioxide and energy is released. That’s why it is considered as an exothermic reaction. C6H12O6(aq)+6O2→6CO2(aq)+6H2O(I)+Energy
In the course of respiration glucose is broken into carbon dioxide and energy is released. That’s why it is considered as an exothermic reaction.
See lessC6H12O6(aq)+6O2→6CO2(aq)+6H2O(I)+Energy
Why are decomposition reactions called the opposite of combination reactions? Write equations for these reactions.
In a combination reaction two or more substances are combined to form new substance while in the decomposition reaction one substance decomposes into two or more substances. Hence, the decomposition reactions are called opposite of combination reactions. Example of decomposition : (i) 2FeSO4(s) Read more
In a combination reaction two or more substances are combined to form new substance while in the decomposition reaction one substance decomposes into two or more substances. Hence, the decomposition reactions are called opposite of combination reactions.
Example of decomposition :
(i) 2FeSO4(s) —Heat→ Fe2O3(s) + SO2(g) + SO3(g)
Example of combination :
(i) CaO(s) + CO2(g) → CaCO3(s)
See lessWhat is the difference between displacement and double displacement reactions? Write equations for these reactions.
When a more reactive element displaces a less reactive element from its salt solution, then it is called displacement reaction. While there is an exchange of ions between the reactants to produce new substances, it is called double displacement reaction. In displacement reaction one displacement takRead more
When a more reactive element displaces a less reactive element from its salt solution, then it is called displacement reaction. While there is an exchange of ions between the reactants to produce new substances, it is called double displacement reaction. In displacement reaction one displacement takes place. While in double displacement reaction two displacements takes place.
Displacement reaction
Mg(s)+2HCl(aq)→MgCl2+H2(g)
Double displacement reaction
See less2KBr(aq)+BaCl2→2Kl(aq)+BaBr3(s)
In the refining of silver, the recovery of silver from silver nitrate solution involved displacement by copper metal. Write down the reaction involved.
2AgNO3(aq)+Cu(s)→Cu(NO3)2(l)+2Ag(s)
2AgNO3(aq)+Cu(s)→Cu(NO3)2(l)+2Ag(s)
See lessWhat do you mean by a precipitation reaction? Explain by giving examples.
Reactions in which precipitate is formed are called precipitation reactions. Generally in a precipitation reaction insoluble salts are settled down as precipitate. Na2SO4(aq)+BaCl2(aq)→BaSO4s+2NaCl(aq) In the above reaction, when sodium sulphate reacts with barium chloride, the white precipitate ofRead more
Reactions in which precipitate is formed are called precipitation reactions. Generally in a precipitation reaction insoluble salts are settled down as precipitate.
Na2SO4(aq)+BaCl2(aq)→BaSO4s+2NaCl(aq)
In the above reaction, when sodium sulphate reacts with barium chloride, the white precipitate of barium sulphate is formed along with the sodium chloride.
See lessExplain the following in terms of gain or loss of oxygen with two examples each.
Oxidation - When a substance gains oxygen or loses hydrogen during a reaction, it is called that the substance is oxidized. This phenomenon is called oxidation. 2Cu + O2 --> 2CuO In this reaction copper gains oxygen and hence is oxidized. CuO + H2 --> Cu + H2O In the above reaction hydroRead more
Oxidation – When a substance gains oxygen or loses hydrogen during a reaction, it is called that the substance is oxidized. This phenomenon is called oxidation.
2Cu + O2 –> 2CuO
In this reaction copper gains oxygen and hence is oxidized.
CuO + H2 –> Cu + H2O
In the above reaction hydrogen gains oxygen, and hence oxidized.
Reduction – If a substance loses oxygen or gains hydrogen during a reaction, it is that the substance is reduced. This phenomenon is called reduction.
ZnO + C → Zn + CO
In this reaction zinc loses oxygen, and hence called is reduced.
MnO2+4HCl→MnCl2+2H2O+Cl2
In this reaction Mangnese dioxide loses oxygen and hence is called reduced.
See lessA shiny brown coloured element ‘X’ on heating in air becomes black in colour. Name the element ‘X’ and the black coloured compound formed.
Copper is a brown coloured shiny element, when heated in air, it becomes black in colour. 2Cu+O2→2CuO Hence, the element ‘X’ is copper and black coloured compound formed is copper oxide.
Copper is a brown coloured shiny element, when heated in air, it becomes black in colour.
2Cu+O2→2CuO
Hence, the element ‘X’ is copper and black coloured compound formed is copper oxide.
See lessWhy do we apply paint on iron articles?
When articles made of iron come in contact with the moisture present in air, it forms iron oxide, which is known as rust. Hence, to prevent an iron article to come in contact with moisture present in air paint is applied. Paint prevents the iron to get rusted.
When articles made of iron come in contact with the moisture present in air, it forms iron oxide, which is known as rust. Hence, to prevent an iron article to come in contact with moisture present in air paint is applied. Paint prevents the iron to get rusted.
See lessOil and fat containing food items are flushed with nitrogen. Why?
When fats and oils are oxidised, they become rancid and their smell and taste change. Hence, food items containing oil and fat are flushed with nitrogen which prevents them to get oxidized and becoming rancid.
When fats and oils are oxidised, they become rancid and their smell and taste change. Hence, food items containing oil and fat are flushed with nitrogen which prevents them to get oxidized and becoming rancid.
See less