CBSE Class 10 > Class 10 Notes > Science > Important Equations and Definitions: Chemical Reactions and Equations
Important Equations and Definitions: Chemical Reactions and Equations | Science Class 10 PDF Download
Chemical Equations
A + B → C + D
In this example, A and B are the reactants, which react to form the products C and D.
Here we can see how the number of each atom on the left side is balanced on the right side, as stated by the law of conservation of mass.
Types of Chemical Reactions
1. Combustion Reaction
2Mg + O₂ → 2MgO
A combustion reaction is a reaction with a combustible material with an oxidizer to give an oxidized product.
2. Decomposition Reaction
CaCO₃ → CaO + CO₂
A Decomposition reaction is a reaction in which a single component breaks down into multiple products.
3. Neutralization Reaction
HCl + NaOH → NaCl + H₂O
A Neutralization reaction is the reaction between an acid and a base giving salt and water as the products.
4. Redox Reaction
Zn + 2H⁺ → Zn²⁺ + H₂
A REDuction-OXidation reaction is a reaction in which there is a transfer of electrons between chemical species.
5. Precipitation or Double-Displacement Reaction
AgNO₃ + NaCl → AgCl + NaNO₃
It is a type of displacement reaction in which two compounds react, and their anions and cations switch places forming two new products.
6. Synthesis Reaction
2Na(s) + Cl₂(g) → 2NaCl(s)
A Synthesis reaction is one of the most basic types of reaction wherein multiple simple compounds combine under certain physical conditions giving out a complex product.
7. Combination Reaction
2H₂ + O₂ → 2H₂O
A Combination reaction is a reaction in which two or more substances combine to form a single product. It is also known as a synthesis reaction where simpler substances react to form a more complex compound.
MULTIPLE CHOICE QUESTIONTry yourself: Which type of chemical reaction involves the transfer of electrons between chemical species?
Important Points to Remember
- In a chemical change, a new compound is formed but in a physical change, the substance changes its state of existence.
- Atoms or ions or molecules which react to form a new substance are called reactants; the new atoms or molecules formed are products.
- A chemical reaction follows the law of conservation of mass. That is no atom is destroyed or created but only a new product is formed from reactants.
The document Important Equations and Definitions: Chemical Reactions and Equations is a part of the Class 10 Course Science Class 10.
All you need of Class 10 at this link: Class 10
FAQs on Important Equations and Definitions: Chemical Reactions and Equations
| 1. What's the difference between a chemical equation and a chemical reaction? |  |
Ans. A chemical reaction is the actual process where substances transform into new products through breaking and forming bonds. A chemical equation is the symbolic representation of that reaction using chemical formulas and symbols. The equation shows what reacts (reactants) and what forms (products), making it easier to understand and balance chemical changes in CBSE Class 10 Science.
| 2. How do I balance a chemical equation step by step? | |
Ans. Balancing involves making atom counts equal on both sides by adjusting coefficients-the numbers before chemical formulas. Count atoms of each element on the reactant and product sides, then adjust coefficients until balanced. This ensures the law of conservation of mass is obeyed. Practice with simple equations first, then progress to complex ones involving multiple elements.
| 3. Why do we write chemical equations with symbols like arrows and plus signs? | |
Ans. Chemical equation symbols communicate information concisely. The arrow (→) shows direction of reaction, plus signs separate substances, and symbols indicate physical states: (s) for solid, (l) for liquid, (g) for gas, and (aq) for aqueous solutions. This standardised notation helps students and scientists worldwide understand reactions consistently without lengthy descriptions.
| 4. What are the different types of chemical reactions and how do I identify them? | |
Ans. Four main types exist: combination (two substances form one), decomposition (one substance breaks into multiple), displacement (element replaces another), and double displacement (ions exchange between compounds). Identify them by observing what bonds break and form. Each type shows distinct patterns: combination reactions release heat, decomposition requires energy, and displacement involves reactivity series concepts crucial for CBSE examinations.
| 5. How do I write a balanced chemical equation from a word equation? | |
Ans. Convert substance names to chemical formulas using the periodic table and valency rules. Write reactants on the left and products on the right separated by an arrow. Balance atoms by adjusting coefficients systematically, starting with metals, then non-metals, and finally hydrogen and oxygen. Verify all elements have equal atom counts on both sides before finalising the balanced equation.
About this Document
40.2K Views
4.68/5 Rating
May 20, 2026 Last updated
Document Description: Important Equations and Definitions: Chemical Reactions and Equations for Class 10 2026 is part of Science Class 10 preparation. The notes and questions for Important Equations and Definitions: Chemical Reactions and Equations have been prepared according to the Class 10 exam syllabus. Information about Important Equations and Definitions: Chemical Reactions and Equations covers topics like and Important Equations and Definitions: Chemical Reactions and Equations Example, for Class 10 2026 Exam. Find important definitions, questions, notes, meanings, examples, exercises and tests below for Important Equations and Definitions: Chemical Reactions and Equations.
Introduction of Important Equations and Definitions: Chemical Reactions and Equations in English is available as part of our Science Class 10 for Class 10 & Important Equations and Definitions: Chemical Reactions and Equations in Hindi for Science Class 10 course. Download more important topics related with notes, lectures and mock test series for Class 10 Exam by signing up for free. Class 10: Important Equations and Definitions: Chemical Reactions and Equations
Description
Important Equations & Definitions: Chemical Reactions & Equations of Science Class 10 covers all the important topics, helping you prepare for the Class 10 exam on EduRev.
Information about Important Equations and Definitions: Chemical Reactions and Equations
In this doc you can find the meaning of Important Equations and Definitions: Chemical Reactions and Equations defined & explained in the simplest way possible. Besides explaining types of Important Equations and Definitions: Chemical Reactions and Equations theory, EduRev gives you an ample number of questions to practice Important Equations and Definitions: Chemical Reactions and Equations tests, examples and also practice Class 10 tests
Related Searches
Objective type Questions, Sample Paper, pdf , Previous Year Questions with Solutions, MCQs, Exam, Summary, Viva Questions, Important questions, past year papers, ppt, practice quizzes, Semester Notes, Important Equations and Definitions: Chemical Reactions and Equations, shortcuts and tricks, Free, Important Equations and Definitions: Chemical Reactions and Equations, study material, Important Equations and Definitions: Chemical Reactions and Equations, mock tests for examination, Extra Questions, video lectures;