Class 9 Important Differences: Science, Social Science & Maths Explained

Class 9 Important Differences: Science, Social Science & Maths Explained

1. DIFFERENCE BETWEEN MIXTURE AND PURE SUBSTANCE

S. NO	CONTENT	MIXTURE	PURE SUBSTANCE
1	Composition	A mixture contains two or more different substances that are physically combined but not chemically bonded	A pure substance consists of only one type of element or compound. It has a uniform and consistent composition throughout
2	Properties	The properties of a mixture depend on the composition and the proportion of the substances that make it up	The properties of a pure substance are consistent and do not change under given conditions
3	Separation	The components of a mixture can be separated by physical methods, such as filtration, distillation, or chromatography.	A pure substance cannot be separated into other substances by physical means
4	Examples	Air (a mixture of gases), seawater (a mixture of water and dissolved salts), and soil (a mixture of various minerals and organic matter).	Oxygen (O₂), carbon dioxide (CO₂), water (H₂O), and iron (Fe)

2.difference between homogeneous mixture and heterogenous mixture

S.NO	CONTENT	HOMOGENEOUS mixture	HETEROGENEOUS mixture
1	Uniformity of Composition:	uniformly distributed	NOT uniformly distributed
2	Appearance:	Appears as a single phase or substance	Appears as multiple phases or substances.
3	Separation of Components:	The components are so well mixed that they can’t be separated easily by physical means.	The components are more easily distinguishable and can often be separated by physical methods
4	Examples:	Air (a mixture of gases like oxygen, nitrogen, etc.). Vinegar (acetic acid dissolved in water). Sugar water (sugar completely dissolved in water).	Pizza (you can see the different ingredients like cheese, sauce, and toppings). Oil and water (where the two substances do not mix and form separate layers). Cereal in milk (you can distinguish between the cereal and milk).

3. difference between colloidal solution and suspension solution ?

S. NO	CONTENT	COLLOIDAL	SUSPENSION
1	Particle Size:	The particles in a colloidal mixture are between 1 nanometer and 1 micrometer in size	The particles in a suspension are larger than those in a colloid, typically greater than 1 micrometer.
2	Appearance:	Colloids often appear homogeneous to the naked eye but are heterogeneous at the microscopic level.	Suspensions are heterogeneous mixtures, and you can easily see the particles suspended in the medium.
3	Stability:	Colloidal mixtures are stable and the particles do not settle over time due to the Brownian motion, which keeps the particles suspended.	Suspensions are unstable, and the particles will settle out over time unless the mixture is constantly stirred or agitated.
4	Examples:	Milk, fog, gelatin, paint, and whipped cream.	Muddy water, sand in water, and salad dressing.

4. Difference between element and compounds

S.NO	CONTENT	ELEMENT	COMPOUND
1	Composition:	An element is a pure substance that consists of only one type of atom.	A compound is a substance made up of two or more different types of atoms that are chemically bonded together.
2	Chemical Bonds:	here are no chemical bonds because it consists of only one type of atom	Atoms of different elements are chemically bonded through covalent or ionic bonds to form a compound.
3	Properties:	The properties of an element are characteristic of the type of atom it contains.	The properties of a compound are often very different from the properties of the elements that make it up.
4	Separation:	Elements cannot be chemically broken down into simpler substances.	Compounds can be broken down into their constituent elements or simpler compounds through chemical reactions.
5	Examples:	Iron (Fe), Helium (He), Carbon (C)	Salt (NaCl), Ammonia (NH₃), Methane (CH₄)

5. Difference Between Metal and Alloy

Basis of Comparison	Metal	Alloy
Definition	A pure chemical element that conducts heat and electricity and has metallic properties.	A mixture of two or more elements, where at least one is a metal.
Composition	Composed of a single type of element (e.g., Iron, Copper, Aluminum).	Composed of two or more elements (e.g., Brass = Copper + Zinc).
Properties	Has natural metallic properties like malleability, ductility, and luster.	Properties are improved (e.g., stronger, resistant to corrosion) than parent metals.
Example	Iron (Fe), Gold (Au), Silver (Ag), Copper (Cu)	Brass, Bronze, Steel, Duralumin
Strength and Hardness	Usually softer and less strong compared to alloys.	Generally harder and stronger than pure metals.

6.Difference Between Colloidal Solution and Suspension

Basis of Comparison	Colloidal Solution	Suspension
Definition	A heterogeneous mixture in which the particle size is intermediate between true solution and suspension.	A heterogeneous mixture in which the particles are large enough to settle down on standing.
Particle Size	1 nm – 100 nm	More than 100 nm
Appearance	Appears homogeneous to the naked eye.	Clearly heterogeneous and particles can be seen.
Settling of Particles	Particles do not settle on standing.	Particles settle on standing.
Filterability	Particles cannot be separated by ordinary filtration but can be separated by ultrafiltration.	Particles can be separated by ordinary filtration.
Tyndall Effect	Shows Tyndall effect (scattering of light).	Shows Tyndall effect only if particles are large and concentrated.
Examples	Milk, fog, ink	Muddy water, sand in water, chalk in water

7.Difference Between Atom and Molecule

Basis of Comparison	Atom	Molecule
Definition	The smallest particle of an element that cannot be broken down further by chemical means.	A group of two or more atoms chemically bonded together.
Nature	May or may not exist independently.	Always exists independently.
Composition	Consists of only one kind of element.	Can be made up of the same or different elements.
Stability	Usually unstable when single.	More stable because atoms are bonded together.
Example	H (Hydrogen atom), O (Oxygen atom)	H₂ (Hydrogen molecule), O₂ (Oxygen molecule), H₂O (Water molecule)
Chemical Bond	Does not contain any chemical bond.	Contains chemical bonds between atoms.

8.Difference Between Atom and Molecule

Basis of Comparison	Atom	Molecule
Definition	The smallest particle of an element that cannot be broken down further by chemical means.	A group of two or more atoms chemically bonded together.
Nature	May or may not exist independently.	Always exists independently.
Composition	Consists of only one kind of element.	Can be made up of the same or different elements.
Stability	Usually unstable when single.	More stable because atoms are bonded together.
Example	H (Hydrogen atom), O (Oxygen atom)	H₂ (Hydrogen molecule), O₂ (Oxygen molecule), H₂O (Water molecule)
Chemical Bond	Does not contain any chemical bond.	Contains chemical bonds between atoms.

9.Difference Between Plant Cell and Animal Cell

Basis of Comparison	Plant Cell	Animal Cell
Cell Wall	Present; made of cellulose, provides rigidity and support.	Absent; only a plasma membrane is present.
Shape	Usually fixed and rectangular due to cell wall.	Usually round or irregular in shape.
Vacuole	One large central vacuole present.	Many small vacuoles or absent.
Plastids (Chloroplasts)	Present (e.g., chloroplast for photosynthesis).	Absent.
Centrioles	Absent (except in lower plant forms).	Present and help in cell division.
Mode of Nutrition	Mostly autotrophic (makes its own food).	Heterotrophic (depends on others for food).
Lysosomes	Rare or absent.	Present and active.
Nucleus Position	Lies at one side (due to large vacuole).	Lies in the center of the cell.
Example	Cell of leaf, stem, root	Cell of liver, skin, muscles

10.Difference Between Prokaryotic and Eukaryotic Cell

Basis of Comparison	Prokaryotic Cell	Eukaryotic Cell
Definition	Cells that lack a true nucleus and membrane-bound organelles.	Cells that have a true nucleus and membrane-bound organelles.
Nucleus	Absent; DNA is present in a region called nucleoid.	Present; DNA is enclosed within the nuclear membrane.
Cell Size	Generally small (1–10 µm).	Larger in size (10–100 µm).
Cell Organization	Simple and primitive.	Complex and advanced.
Membrane-Bound Organelles	Absent (e.g., no mitochondria, ER, Golgi body).	Present (e.g., mitochondria, ER, Golgi body).
Cell Division	Occurs by binary fission.	Occurs by mitosis or meiosis.
Example Organisms	Bacteria, Blue-green algae (Cyanobacteria).	Plants, Animals, Fungi, Protists.

11.Difference Between Isotonic, Hypertonic, and Hypotonic Solutions

Basis of Comparison	Isotonic Solution	Hypertonic Solution	Hypotonic Solution
Definition	A solution having the same concentration of solute as the cell cytoplasm.	A solution having higher concentration of solute than the cell cytoplasm.	A solution having lower concentration of solute than the cell cytoplasm.
Water Movement	No net movement of water across the cell membrane.	Water moves out of the cell.	Water moves into the cell.
Effect on Cell	Cell remains unchanged in size.	Cell shrinks (plasmolysis in plant cells).	Cell swells and may burst (lysis in animal cells).
Example	0.9% NaCl solution for human blood cells.	Concentrated salt or sugar solution.	Pure water or very dilute solution.
Osmosis Direction	Dynamic equilibrium maintained.	From cell to solution (outward).	From solution to cell (inward).

12.Difference Between Mitosis and Meiosis

Basis of Comparison	Mitosis	Meiosis
Definition	Type of cell division in which one parent cell divides to form two identical daughter cells.	Type of cell division in which one parent cell divides to form four non-identical daughter cells.
Number of Divisions	Involves one cell division.	Involves two cell divisions (Meiosis I and Meiosis II).
Chromosome Number	Daughter cells have the same number of chromosomes as the parent (diploid).	Daughter cells have half the number of chromosomes as the parent (haploid).
Genetic Composition	Genetically identical to the parent cell.	Genetically different from the parent cell.
Occurs In	Somatic (body) cells.	Reproductive (germ) cells.
Purpose	For growth, repair, and replacement of cells.	For formation of gametes (sperm and egg cells).
Crossing Over	Does not occur.	Occurs during Prophase I, leading to variation.
Example	Skin cell division.	Formation of sperm or egg cells.

Class 9 Important Differences: Science, Social Science & Maths Explained

13.Difference Between Cell Wall and Plasma Membrane

Basis of Comparison	Cell Wall	Plasma Membrane (Cell Membrane)
Definition	A rigid outer layer that surrounds the cell membrane in plant cells, bacteria, and fungi.	A thin, flexible membrane that surrounds the cytoplasm of all cells.
Occurrence	Present in plant cells, bacteria, and fungi.	Present in both plant and animal cells.
Composition	Made up of cellulose (in plants), chitin (in fungi), or peptidoglycan (in bacteria).	Made up of lipids and proteins (lipid bilayer).
Nature	Rigid and non-living structure.	Flexible and living structure.
Function	Provides protection, shape, and support to the cell.	Controls entry and exit of substances; maintains homeostasis.
Permeability	Fully permeable (allows most substances to pass).	Selectively permeable (allows only certain substances to pass).
Position	Lies outside the plasma membrane.	Lies inside the cell wall (in plants).