ExamSupportExamSupportGet complete CBSE Class 10 Science notes for Chemical Reactions and Equations. You can easily study reaction types, balancing equations, and the periodic table for your board exams.
PDF not yet available
Please check back later or browse other notes.
A chemical reaction is a process where substances transform into new substances with entirely different properties. You can confirm a chemical reaction has taken place if you observe:
A chemical equation represents a chemical reaction using symbols and formulas. You write the reacting substances (reactants) on the left side and the new substances formed (products) on the right side.
An unbalanced or skeletal chemical equation has an unequal number of atoms for one or more elements on the reactant and product sides.
The Law of Conservation of Mass dictates that mass can neither be created nor destroyed in a chemical reaction. You must balance chemical equations so that the total number of atoms of each element remains identical on both sides.
To balance an equation, multiply the chemical formulas by whole numbers called coefficients.
Two or more reactants combine to form a single product. When quicklime reacts with water, it forms slaked lime.
A single reactant breaks down to yield two or more simpler products. This process requires energy such as heat, light, or electricity.
Heating ferrous sulphate produces ferric oxide, sulphur dioxide, and sulphur trioxide.
Passing electric current through water separates it into hydrogen and oxygen gases.
Silver chloride breaks down into silver and chlorine when exposed to sunlight.
A more reactive element takes the place of a less reactive element in its compound. Iron displaces copper from copper sulphate.
Two compounds react by exchanging their ions to form two new compounds.
Any chemical reaction that produces an insoluble solid is called a precipitation reaction. In the above equation, barium sulphate is formed as a white precipitate.
These reactions release energy in the form of heat or light.
These reactions absorb energy from surroundings.
A substance undergoes oxidation when it gains oxygen or loses hydrogen.
A substance undergoes reduction when it loses oxygen or gains hydrogen.
One reactant is oxidized and the other is reduced.
Here, $CuO$ is reduced to $Cu$ and $H_2$ is oxidized to $H_2O$.
This section organizes historical and modern methods used to classify elements.
Johann Wolfgang Döbereiner grouped elements with similar properties into triads. The atomic mass of the middle element is approximately the average of the other two.
Example: Lithium, Sodium, Potassium
John Newlands arranged elements in increasing atomic mass. Every eighth element showed similar properties. This worked only up to calcium.
Dmitri Mendeléev arranged elements based on atomic mass and chemical properties.
Periodic Law:
Properties of elements are periodic functions of their atomic masses.
He predicted undiscovered elements and left gaps in his table.
Henry Moseley proved atomic number is more fundamental than atomic mass.
Modern Periodic Law:
Properties of elements are periodic functions of their atomic numbers.
The modern periodic table contains:
Elements on the left side are metals.
Metals lose electrons and form positive ions.
Elements on the right side are nonmetals.
Nonmetals gain electrons and form negative ions.
Across a period
Metallic character decreases
Nonmetallic character increases
Down a group
Metallic character increases
Magnesium burning in air
$$
2Mg + O_2 \rightarrow 2MgO
$$
Calcium oxide with water
$$
CaO + H_2O \rightarrow Ca(OH)_2
$$
Hydrogen with chlorine
$$
H_2 + Cl_2 \rightarrow 2HCl
$$
Heating calcium carbonate
$$
CaCO_3 \xrightarrow{heat} CaO + CO_2
$$
Heating ferrous sulphate
$$
2FeSO_4 \xrightarrow{heat} Fe_2O_3 + SO_2 + SO_3
$$
Heating lead nitrate
$$
2Pb(NO_3)_2 \xrightarrow{heat} 2PbO + 4NO_2 + O_2
$$
Electrolysis of water
$$
2H_2O \xrightarrow{electricity} 2H_2 + O_2
$$
Silver chloride in sunlight
$$
2AgCl \xrightarrow{sunlight} 2Ag + Cl_2
$$
Silver bromide in sunlight
$$
2AgBr \xrightarrow{sunlight} 2Ag + Br_2
$$
Iron displacing copper
$$
Fe + CuSO_4 \rightarrow FeSO_4 + Cu
$$
Zinc displacing copper
$$
Zn + CuSO_4 \rightarrow ZnSO_4 + Cu
$$
Copper displacing silver
$$
Cu + 2AgNO_3 \rightarrow Cu(NO_3)_2 + 2Ag
$$
Sodium sulphate and barium chloride
$$
Na_2SO_4 + BaCl_2 \rightarrow BaSO_4 + 2NaCl
$$
Lead nitrate and potassium iodide
$$
Pb(NO_3)_2 + 2KI \rightarrow PbI_2 + 2KNO_3
$$
Sodium chloride and silver nitrate
$$
NaCl + AgNO_3 \rightarrow AgCl + NaNO_3
$$
Barium sulphate formation
$$
Na_2SO_4 + BaCl_2 \rightarrow BaSO_4 \downarrow + 2NaCl
$$
Lead iodide formation
$$
Pb(NO_3)_2 + 2KI \rightarrow PbI_2 \downarrow + 2KNO_3
$$
Silver chloride formation
$$
AgNO_3 + NaCl \rightarrow AgCl \downarrow + NaNO_3
$$
Methane combustion
$$
CH_4 + 2O_2 \rightarrow CO_2 + 2H_2O + heat
$$
Glucose respiration
$$
C_6H_{12}O_6 + 6O_2 \rightarrow 6CO_2 + 6H_2O + energy
$$
Quicklime with water
$$
CaO + H_2O \rightarrow Ca(OH)_2 + heat
$$
Calcium carbonate decomposition
$$
CaCO_3 \xrightarrow{heat} CaO + CO_2
$$
Electrolysis of water
$$
2H_2O \xrightarrow{electricity} 2H_2 + O_2
$$
Copper oxide with hydrogen
$$
CuO + H_2 \xrightarrow{heat} Cu + H_2O
$$
Zinc with hydrochloric acid
$$
Zn + 2HCl \rightarrow ZnCl_2 + H_2
$$
Iron oxide with carbon monoxide
$$
Fe_2O_3 + 3CO \rightarrow 2Fe + 3CO_2
$$
Rusting of iron
$$
4Fe + 3O_2 + xH_2O \rightarrow 2Fe_2O_3 \cdot xH_2O
$$
Oxidation of oils (general form)
$$
Oil + O_2 \rightarrow Oxidized\ products
$$
These appear most often:
These Complete CBSE Class 10 Science Notes: Chemical Reactions and Equations notes are structured as a revision tool — not a textbook reproduction. Every section prioritises what the Class 10th Science Notes (CBSE and State Boards) exam actually tests: key definitions, formulas in context, and the concepts that appear most frequently in previous year papers.
Content is aligned with the current Class 10th Science Notes (CBSE and State Boards) syllabus. Important points are front-loaded so you can scan the critical material in minutes during a revision session — whether that is the night before a mock test or the final week before the exam.
For the best results, pair these notes with previous year Class 10th Science Notes (CBSE and State Boards) papers. Notes build the knowledge base; past papers reveal how the examiner uses that knowledge to frame questions and distribute marks.
All materials are shared strictly for educational purposes. Always refer to official textbooks and board guidelines for complete accuracy.
Read the chapter from your textbook before opening these notes. Notes consolidate — they cannot replace first learning.
Cover each formula or definition and try to recall it. Every gap you find is a specific, fixable weakness.
20 min now, 10 min in a week, 5 min the week after. Spaced repetition beats a single careful reading every time.
After revising a chapter, solve 10–15 Class 10th Science Notes (CBSE and State Boards) past-paper questions from it. Notes tell you what; papers show you how.
Yes. These notes are completely free — no account, no subscription, and no payment required at any point. Click download and the PDF is yours instantly.
Yes. All Class 10th Science Notes (CBSE and State Boards) notes on ExamSupport are verified against the current official syllabus before publishing. They reflect the latest exam pattern and curriculum.
Yes. The PDF downloads directly to your device. Open it in any PDF reader app — no internet connection needed while studying.
Notes are revision tools, not primary learning tools. Study your textbook first, then use these notes to consolidate and revise. Using notes as your only source is not recommended.
ExamSupport provides free, chapter-wise Complete CBSE Class 10 Science Notes: Chemical Reactions and Equations study notes in PDF format for students preparing for Class 10th Science Notes (CBSE and State Boards). The notes on this page are available for immediate download without any registration or payment.
Each note is structured around what the Class 10th Science Notes (CBSE and State Boards) exam actually tests — key definitions, formulas in context, and the concepts with the highest frequency in previous year papers. The format is designed for spaced revision: concise enough to review in 15–20 minutes, comprehensive enough to cover every exam-critical point in the chapter.
For maximum benefit, use these Complete CBSE Class 10 Science Notes: Chemical Reactions and Equations notes alongside Class 10th Science Notes (CBSE and State Boards) previous year question papers also available free on ExamSupport. Notes build the knowledge base; papers reveal exactly how that knowledge is tested under exam conditions.
All materials are shared strictly for personal educational use. Always cross-reference with official textbooks and your school or coaching faculty for complete accuracy.