Chemical reactions and equations class 10 notes
Chemical reactions and equations class 10 notes
Chemical reaction and equation class 10 notes. Here is the collection of all topic in chemical reactions and equation for class 10 CBSE board. All topic are explained in detail.
Chemical reaction:-
- Chemical reactions are the process in which new substance are formed with new properties.
- During chemical reaction reactant converted into product which has entirely different properties compared to reactant.
- During chemical reactions a chemical change takes place and a new chemical bond takes place between atoms of a compound of product.
- Example:- burning of wood
C + O2 = CO2
Carbon + oxygen = carbon dioxide
we recognise a chemical reaction has been take place or not by the characteristic of chemical reaction.
now we have an idea what is chemical reaction and what is the example of chemical reaction but how to recognise a chemical reaction has taken place or not.
so we have to study the characteristic of chemical reaction by which we can recognise the chemical reaction has been take place or not.
Characteristic of chemical reaction:-
Chemical reaction can be classified by the following ways:-
- Evolution of gas
- Formation of precipitate.
- Change in colour.
- Change in temperature.
- Change in state.
Evolution of gas
- If We combine carbon with oxygen then carbon dioxide gas is produced and a lot of heat is also released.
For example:-
Carbon + oxygen = carbon dioxide
Here carbon and oxygen combine and carbon dioxide gas is evaluate this show the evolution of gas like carbon dioxide.
- if zinc combines with hydrogen sulphate and zinc sulphate and hydrogen gas is produced.
Formation of precipitate:-
potassium iodide solution is added to a solution of lead nitrate then a yellow precipitate of lead iodide is formed.
KI + PbNo3 = Pb I + KNo3
H2SO4 + BaCl2 = BaSO4 + HCl
Change in colour:-
when Sulphur dioxide gas is passed through acidified potassium dichromate solution then the orange colour of potassium dichromate changes to green.
Change in temperature:-
CaO + H2O = Ca(OH)2 + Heat
This reaction is also known as heat producing reaction or exothermic reaction.
Zn + H2SO4 = ZnSO4 + H2 + heat
In what reaction change in temperature occurs or (rise in temperature).
Ba(OH)2 + NH4Cl + heat = BaCl + NH4 + H2O
in this reaction heat is not produced while heat is absorbed. so this reaction is known as endothermic reaction due to this, reaction become cold and a fall of temperature occur.
Change in state:-
If we burn wax ( candle ) candle then, wax which is in the state of solid burn and produce liquid and flame produces gas so during this reaction ia changen state takes place.
CaO + H2O = Ca(OH)2
Chemical equation:-
- A chemical equation is the method to represent a chemical reaction which is in word equation with the help of symbol and formula.
- in most simple word we can say that it is the short hand method to represent a chemical reaction.
- Example hydrogen + oxygen = water
Balanced and unbalanced chemical equations
Balanced chemical equation:-
It has equal number of atom in reactant and product.
2H2 + O2 = 2H2O
In reactant
Number of atom of hydrogen is 4
Number of oxygen atom is 2.
In product
Number of hydrogen atom is also 4.
Number of oxygen atom is also 2.
So we can say that this equation is balanced.
Law of conservation of mass in a chemical reaction
Note:- chemical equation are balanced to satisfy the law of conservation of mass in a chemical reaction.
Unbalanced chemical reaction:-
It has an equal number of atom in reactant and product.
Mg + O2 = MgO
Reactivity series of metal
- Potassium is more reactive metal.
- Sodium Na
- Barium Ba
- Calcium Ca
- Magnesium Mg
- Aluminium
- Zinc
- Iron
- Cobalt
- Nickel
- Tin
- Lead
- Hydrogen
- Copper
- Mercury
- Silver
- Gold
- Platinum is less reactive metal
Potassium metal is more reactive and platinum metal is less reactive.
Potassium is most reactive therefore it can lose its valence electron most easily.
A more reactive metal can displace a less reactive metal.
Example:- CuSO4 +Zn = ZnSO4 + Cu
Here Zinc is more reactive than copper. So zinc displace copper.
Types of reaction:-
Combination reaction:- when two or more element or substances combined together and form a single substance or compound is called combination reaction.
This type of chemical reaction takes place in the presence of heat, light or electricity.
Double displacement reaction:- Those reaction in which two or more ionic compound exchange their corresponding ions is known as double displacement reaction.
Decomposition reaction:- Those reaction in which a compound spilt up into two or more similar substance is known as decomposition reaction.
Displacement reaction:- Those reaction in which a more reactive metal displace a less reactive metal from its solution.
Neutralization reaction:- when acid and base react together then salt and water is formed.
Oxidation and reduction:-
Oxidation means addition of Oxygen and removal of hydrogen.
Reduction means addition of hydrogen and removal of oxygen.
Redox reaction:- Any reaction in which electrons are exchange between atoms or ions represent simultaneously process of oxidation, reduction is called redox reaction.
In redox reaction the species which loss one or more electron is known as reducing agent.
and the species which gain or one or more electron is known as oxidising agent.
Q.1. What is chemical reaction for class 10?
A chemical reaction is the process in which a new substances are formed with new properties. In a chemical reaction a rearrangement of particles or atoms/molecules takes place.
Q.2. What is chemical equation?
In simple word we can say that a chemical equation is a short cut or short hand method to represent a chemical reaction.
Q.3. What are the characteristic of chemical reaction with example?
These are the characteristic of a chemical reaction
Evolution of gas
example:- Carbon + oxygen = carbon dioxide
Formation of precipitate.
example:- KI + PbNo3 = Pb I + KNo3
Change in colour.
example:- when Sulphur dioxide gas is passed through acidified potassium dichromate solution then the orange colour of potassium dichromate changes to green
Change in temperature.
example:- CaO + H2O = Ca(OH)2 + Heat
Change in state.
example:- CaO + H2O = Ca(OH)2
Q.4. What are the 4 types of chemical reaction?
The four types of chemical reactions are as follows:-
Combination reaction
Decomposition reaction
Displacement reaction
Double displacement reaction
Q.5. Is color change a chemical reaction?
the answer is yes a chemical reaction can change a color.