Chemistry, often referred to as the "central science," is a subject that delves into the very essence of matter and its transformations. One of the fundamental concepts that students encounter in their Class 10 CBSE NCERT curriculum is chemical equations
Decoding the Alchemy: Mastering Chemical Equations in Class 10 Science
Let's embark on a fascinating journey into the world of chemical equations, where symbols and formulas dance to reveal the hidden stories of reactions. Chemical equations are symbolic representations of chemical reactions in which the reactants and the products are expressed in terms of their respective chemical formulae.
Understanding the Basics
At its core, a chemical equation is a symbolic representation of a chemical reaction. It provides a concise way to convey essential information about the reactants and products involved, making it a powerful tool for chemists to communicate and understand transformations at the molecular level.
What is a Chemical Equation?
Chemical equations make use of symbols to represent factors such as the direction of the reaction and the physical states of the reacting entities. Chemical equations were first formulated by the French chemist Jean Beguin in the year 1615. Chemical reactions can be represented on paper with the help of chemical equations, an example of which is represented below (for the reaction between hydrogen gas and oxygen gas to form water).2H2 + O2 → 2H2O
Symbols of Elements and Their Valencies
A symbol is a chemical code for an element. Each element has a one or two-letter atomic symbol, which is, in most cases, the abbreviated form of its name.
Valency is the combining capacity of an element. It can be considered as the number of electrons lost, gained or shared by an atom when it combines with another atom to form a molecule.
Writing Chemical Equations
Representation of a chemical reaction in terms of symbols and chemical formulae of the reactants and products is known as a chemical equation.
• For solids, the symbol is “(s)”.
• For liquids, it is “(l)”.
• For gases, it is “(g)”.
• For aqueous solutions, it is “(aq)”.
• For gas produced in the reaction, it is represented by “(↑)”.
• For precipitate formed in the reaction, it is represented by “(↓)”.
Balancing of a Chemical Reaction
Law of Conservation of Mass
According to the Law of Conservation of Mass, no atoms can be created or destroyed in a chemical reaction, so the number of atoms for each element on the reactants side has to balance the number of atoms that are present on the products side.
In other words, the total mass of the products formed in a chemical reaction is equal to the total mass of the reactants participating in a chemical reaction.
Balanced chemical equation
The chemical equation in which the number of atoms of each element on the reactants side is equal to that of the products side is called a balanced chemical equation.
The General Form: A typical chemical equation consists of reactants on the left side and products on the right side, separated by an arrow indicating the direction of the reaction. The numbers preceding the chemical formulas, known as coefficients, represent the stoichiometry of the reaction, providing insights into the ratio of reactants and products.
Balancing Act: One of the early challenges students face is balancing chemical equations. This crucial step ensures the conservation of mass, reflecting the fundamental principle that matter is neither created nor destroyed in a chemical reaction. The art of balancing involves adjusting coefficients to achieve equilibrium on both sides of the equation.
Stoichiometry Unveiled: Chemical equations go beyond being mere symbolic representations; they offer a window into the world of stoichiometry. The coefficients in a balanced equation reveal the mole ratios of reactants and products, enabling precise calculations of quantities involved in a reaction. This mathematical aspect adds depth to our understanding of chemical transformations.
Classifying Reactions: Chemical equations also serve as a guide to categorize different types of reactions. Students encounter various classifications, such as synthesis, decomposition, displacement, and double displacement reactions. These categories provide a structured approach to analyzing and predicting the outcomes of diverse chemical processes.
Real-World Applications: The relevance of chemical equations extends far beyond the classroom. From understanding the combustion of fuels to elucidating biological processes within our bodies, chemical equations are the language through which scientists decipher the complexities of the natural world. An appreciation of these equations is vital for anyone curious about the intricate dance of atoms and molecules.
Types of Chemical Reactions
Taking into consideration different factors, chemical reactions are grouped into multiple categories.
A few examples are:
● Single Displacement
● Double displacement
Steps for Balancing Chemical Equations
The changes that occur during a chemical reaction are represented by a chemical equation.
Reactants → Products
The equilibrium of all chemical equations must be maintained. This means that on both sides of the arrow, the number of each sort of atom must be the same.
Chemical equations are balanced using coefficients. A coefficient is a numerical value that is added to the front of a chemical symbol or formula. It indicates the number of atoms or molecules of the material involved in the process.
Place coefficients in front of symbols or formulas as needed to balance a chemical equation so that the same number of each type of atom appears in both reactants and products.
Zn + HCl → ZnCl2 + H2
The balanced equation is
Zn + 2HCl → ZnCl2 + H2
Hit and trial method: While balancing the equation, change the coefficients (the numbers in front of the compound or molecule) so that the number of atoms of each element is the same on each side of the chemical equation.
SAMPLE PRACTICE QUESTION
Q:1 What is a chemical equation?
Ans: A chemical equation is a symbolic representation of a chemical reaction, showing the reactants and products involved and their respective quantities.
Q: 2 How are chemical equations written?
Ans: Chemical equations are written by using chemical symbols and formulas for reactants and products. Reactants are placed on the left side, and products are on the right side of the equation.
Q:3 Why is balancing a chemical equation important?
Ans: Balancing a chemical equation is important to satisfy the law of conservation of mass, ensuring that the number of atoms of each element is the same on both sides of the equation.
Q:4 What does the arrow in a chemical equation represent?
Ans: The arrow in a chemical equation points from the reactants to the products and indicates the direction of the chemical reaction. It shows the transformation of reactants into products.
Q:5 How do you balance a chemical equation?
Ans: To balance a chemical equation, adjust the coefficients in front of the chemical formulas to ensure that the number of atoms for each element is the same on both sides of the equation.
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|CBSE CLASS 10 Mathematics Chapters
|Chapter1: Real Numbers
|Chapter3: Pair of Linear Equations in Two Variables
|Chapter4: Quadratic Equations
|Chapter5: Arithmetic Progressions
|Chapter7: Coordinate Geometry
|Chapter8: Introduction to Trigonometry
|Chapter9: Some Applications of Trigonometry
|Chapter11: Areas Related to Circles
|Chapter12: Surface Areas and Volumes
|CBSE CLASS 10 Science Chapters
|Chapter1: Chemical Reactions and Equations
|Chapter2: Acids, Bases and Salts
|Chapter3: Metals and Non-metals
|Chapter4: Carbon and its Compounds
|Chapter5: Life Processes
|Chapter6: Control and Coordination
|Chapter7: How do Organisms Reproduce?
|Chapter9: Light – Reflection and Refraction
|Chapter10: The Human Eye and the Colourful World
|Chapter12: Magnetic Effects of Electric Current
|Chapter13: Our Environment