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  2. Chemistry - Wikipedia

    en.wikipedia.org/wiki/Chemistry

    Chemistry is the scientific study of the properties and behavior of matter. [1] It is a physical science within the natural sciences that studies the chemical elements that make up matter and compounds made of atoms, molecules and ions: their composition, structure, properties, behavior and the changes they undergo during reactions with other substances.

  3. Secondary School Certificate - Wikipedia

    en.wikipedia.org/wiki/Secondary_School_Certificate

    Secondary School Certificate is a public exam for classes 9 and 10 separately. Class 9 exam is called SSC part-1 and class 10 exam is called SSC part-2. This exam is conducted by government boards, officially known as Boards of Intermediate and Secondary Education, or simply BISE.

  4. Board examination - Wikipedia

    en.wikipedia.org/wiki/Board_examination

    The 2025 CBSE board examination for Class 10 were held from 15 February till 18 March and from 15 February till 4 April for class 12. The usual starting time for each exam was 10:30 am( IST ) but depending on the length and/or maximum marks for the subject, the finishing time was either 12:30 pm ( IST ) (2 hours, shorter exams, usually 40-50 ...

  5. All India Secondary School Examination - Wikipedia

    en.wikipedia.org/wiki/All_India_Secondary_School...

    All India Secondary School Examination, commonly known as the class 10th board exam, is a centralized public examination that students in schools affiliated with the Central Board of Secondary Education, primarily in India but also in other Indian-patterned schools affiliated to the CBSE across the world, taken at the end of class 10. The board ...

  6. Chemistry education - Wikipedia

    en.wikipedia.org/wiki/Chemistry_education

    Chemistry education (or chemical education) is the study of teaching and learning chemistry. It is one subset of STEM education or discipline-based education research (DBER). [1] Topics in chemistry education include understanding how students learn chemistry and determining the most efficient methods to teach chemistry.

  7. Outline of chemistry - Wikipedia

    en.wikipedia.org/wiki/Outline_of_chemistry

    The following outline acts as an overview of and topical guide to chemistry: . Chemistry is the science of atomic matter (matter that is composed of chemical elements), especially its chemical reactions, but also including its properties, structure, composition, behavior, and changes as they relate to the chemical reactions.

  8. Substitution reaction - Wikipedia

    en.wikipedia.org/wiki/Substitution_reaction

    The two reactions are named according tho their rate law, with S N 1 having a first-order rate law, and S N 2 having a second-order. [2] S N 1 reaction mechanism occurring through two steps. The S N 1 mechanism has two steps. In the first step, the leaving group departs, forming a carbocation (C +). In the second step, the nucleophilic reagent ...

  9. Chemical element - Wikipedia

    en.wikipedia.org/wiki/Chemical_element

    Natural carbon is a mixture of 12 C (about 98.9%), 13 C (about 1.1%) and about 1 atom per trillion of 14 C. Most (54 of 94) naturally occurring elements have more than one stable isotope. Except for the isotopes of hydrogen (which differ greatly from each other in relative mass—enough to cause chemical effects), the isotopes of a given ...