Chemical Composition, Formulas, and the Mole Explained
Compounds Display Constant Composition
Another indicator that can be used to distinguish compounds from mixtures is the proportions of elements.
Law of Constant Composition
The law of constant composition: All samples of a given compound have the same proportions of their constituent elements. Water will always have 1 oxygen for every 2 hydrogen atoms (H2O).
Chemical Formulas: How to Represent Compounds
Chemical formula
Chemical formula: Indicates the elements present in a compound and the relative number
Read MoreChemical Bonding, Polarity, Reactions and Intermolecular Forces
Endothermic Reactions
An endothermic reaction absorbs energy.
- Heat (kJ) is written on the reactant side.
- Bonds are broken; no new bonds are formed.
- On Table I, the heat of reaction is positive (+).
- The surroundings feel colder because energy is absorbed.
Exothermic Reactions
An exothermic reaction releases energy.
- Heat (kJ) is written on the product side.
- Bonds are formed.
- On Table I, the heat of reaction is negative (−).
- The surroundings feel warmer because energy is released.
Electronegativity
- Electronegativity
Volumetric and Salt Analysis Techniques for Chemistry
Volumetric Analysis (Titration)
Experiment: KMnO4 vs Mohr’s salt (Ferrous ammonium sulfate)
Indicator: Self-indicator (KMnO4)
End point: Colourless → Permanent light pink
Ionic equations:
- Reduction: MnO4– + 8H+ + 5e– → Mn2+ + 4H2O
- Oxidation: Fe2+ → Fe3+ + e–
Rapid Viva Questions
- Why add dilute H2SO4?
- Provides an acidic medium and prevents KMnO4 from getting reduced to MnO2 (brown precipitate).
- Why not HCl?
- HCl reduces KMnO4, producing Cl2 gas.
- Why not HNO3?
- Strong oxidizer; interferes with the reaction.
Kerala SSLC Chemistry Sure Questions & Revision Notes
Kerala SSLC Chemistry Sure Questions (Model Papers)
To help you prepare effectively for the Kerala SSLC Chemistry exam, I have analyzed the official SCERT Model Question Papers (Sets A, B, and C). Below are the “Sure Questions” that appear frequently across all sets, followed by Microbit-style short notes designed for quick revision.
Part 1: SSLC Chemistry “Sure Questions” (Based on Model Papers)
Based on the patterns in the provided documents, these topics are guaranteed to carry high weightage:
- Subshell
Nuclear Power Generation: Technology and Future Outlook
How Nuclear Power Plants Generate Electricity
Nuclear power plants are facilities designed to generate electricity using the energy released in nuclear fission reactions. Their operation is based on the use of fissile materials such as uranium-235, plutonium-239, or in some cases special mixtures for advanced reactors. When a uranium nucleus is struck by a neutron, it splits into two lighter fragments and releases a large amount of energy in the form of heat, while also emitting neutrons that can
Read MoreOrganic Functional Groups: Alkyl Halides, Alcohols, Carbonyls
FGI: Functional Group Interconversions
Alkyl Halides
Alkyl halides (haloalkanes)
- Alkyl halide or haloalkanes.
- Compounds with a halogen atom bonded to a saturated sp3-hybridized carbon atom.
- Halogen atomic radius increases down the periodic table.
- Lengths of corresponding carbon–halogen bonds increase accordingly, while C–X bond strengths decrease going down the periodic table.
- The carbon–halogen bond of alkyl halides is polarized: the carbon atom bears a slight positive charge (δ+), and the halogen