Explanation:Chemical ReactionDefinition:When two or more substances react and form some new substance, it is called a chemical reaction.Let us see few activities related to chemical reaction:chemical reaction1. Burning of magnesium ribbon: the magnesium ribbon we bring has a layer of carbonate on it so before burning it needs to be CLEANED with sandpaper.Products : magnesium oxide (white color_MgO)Identification property of reaction: white dazzling flamechemical reaction2.Reacting zinc granules with dilute sulphuric acidChemical reaction : H2So4+Zn--- ZnSo4+H2Products : zinc-sulphate and HYDROGEN gasIdentification: beaker becomes hot and hydrogen gas is produced which MAKES match stick burn with pale blue flame and popping sound. chemical reaction3.Reacting barium iodide with lead chlorideChemical reaction : BaI+PbCl2→BaCL2+PbProducts : barium chloride white color and yellow color precipitate of lead iodide. Top Related - Tips to score 95% in Class 10 Science PAPER Characteristics of a chemical reaction    It is either accompanied by a change in colour.    It either leads to a change in state.    Heat energy is produced or absorbed.    Precipitate is formed.    Gas is released. Top Chemical Equation and BalancingChemical equation: it is the representation of chemical reaction in terms of symbols, molecularformulas, moles, states, etc.As we know, all chemical reaction obeys law of chemical combination. Therefore, chemicalreactions need to be balanced. It is done by HIT and trial method. (For practice, questions aresolved in the end). Top Class 10 Science ChaptersOur Environment  Sources of Energy Sustainable Management of Natural ResourcesMagnetic Effect of Electric Current