CBSC Science

                        WHAT IS PHOTOSYNTHESIS? Photosynthesis is the process by which plants, algae, and some bacteria convert light energy into chemical energy in the form of glucose and other organic compounds. It is a complex biochemical process that occurs in the chloroplasts of plant cells and involves the absorption of light by pigments such as chlorophyll. The overall equation for photosynthesis is: 6CO2 + 6H2O + light energy → C6H12O6 + 6O2 In this equation, carbon dioxide (CO2) and water (H2O) are converted into glucose (C6H12O6) and oxygen (O2) through a series of reactions that involve the transfer of electrons and the formation of ATP, a molecule that stores energy. Photosynthesis occurs in two main stages: the light-dependent reactions and the light-independent reactions. In the light-dependent reactions, light energy is absorbed by chlorophyll and other pigments, and used to generate ATP and NADPH, which are ener...

  HOW TO STUDY CLASS 10TH SCIENCE SUBJECT Science Study Tips How to study class 10th science Studying for class 10th science can be challenging, but with the right approach and strategies, you can make the process more effective and efficient. Here are some tips to help you study science: 1) Understand the syllabus: Familiarize yourself with the syllabus to know what topics you need to cover. Break it down into smaller sections or chapters to make it more manageable. 2) Create a study schedule: Plan a study schedule that allocates specific time slots for science. Consistency is key, so try to stick to your schedule as much as possible. 4) Organize your notes: Keep your class notes, textbooks, and any other study materials organized. Use dividers or separate notebooks for different topics to easily locate information when you need it. 5) Read the textbook: Begin by reading the chapter from your textbook to get a general understanding of the concepts. Pay attention to headings, subhe...

                   CHAPTER NUMBER I ---------------------------------------------------------------------------- CHEMICAL REACTION AND EQUATION  * Chemical reaction : -               A chemical reaction is a process in which one or more substances are converted into one or more different substances. During a chemical reaction, the bonds between atoms in the reactants are broken and new bonds are formed to create the products.  Chemical reactions can be represented by chemical equations, which show the reactants on the left-hand side of the equation and the products on the right-hand side. For example, the chemical equation for the reaction between hydrogen gas (H2) and oxygen gas (O2) to form water (H2O) is:  2H2 + O2 → 2H2O  This equation shows that two molecules of hydrogen gas and one molecule of oxygen gas react to form two molecules of water.  * Chemical reactions can ...

*Reactivity Series :-    Reactivity series of metals The Arrangement of elements according to their reactivity is called reactivity series. * Reaction Of Metals with water. Metal react with water to form metal hydroxide and hydrogen gas is released Metal +water ------->metal hydroxide +hydrogen gas Na (s)  + cold H2O (l) ------------>NaOH (aq)+H2(g) K (s) + cold H2O (l) ---------> KOH (aq) + H2 (g) Note:-  Some Metals react with cold water: Sodium and Potassium are the metals which reacts with cold water. * Metals reacts with hot water Some Metals react with hot water: Calcium and Magnesium are the metals which reacts with hot water. Ca (s) + hot H2O (l)  --------> Ca(OH)2 (aq) Mg(s) + hot H20 (l) ----------> Mg(OH)2 (aq) Note:-  Some react with steam:Metals like Iron, Zinc and Aluminium react with steam *when iron reacts with steam : Fe (s)+steam H2O(l)--------->Fe3O4(s) + H2 (g) Some elements don't reacts:- Elements bel...

I) Reactivity Series: -            The Arrangement of elements according to their reactivity is called reactivity series. II) Reaction Of Metals with water.          Metal react with water to form metal hydroxide and hydrogen gas is released Metal +water ------->metal hydroxide +hydrogen gas Na (s) + cold H2O (l) ------------>NaOH (aq)+H2(g) K (s) + cold H2O (l) ---------> KOH (aq) + H2 (g) ✓Some Metals react with cold water:  Sodium and Potassium are the metals which reacts with cold water. ✓Some Metals react with hot water:  Calcium and Magnesium are the metals which reacts with hot water. Ca (s) + hot H2O (l) --------> Ca(OH)2 (aq) Mg(s) + hot H20 (l) ----------> Mg(OH)2 (aq) ✓Some metals react with steam:        Metals like Iron, Zinc and Aluminium react with steam ✓when iron reacts with steam :  Fe (s)+steam H2O(l)--------->Fe3O4(s) +H2 (g) ✓Some elements don't reacts:-...

  Metals and Non- Metals full explaination Class 10 Science Chapter 3 - Metals and non metals Element: Is a substance that can’t be broken into more simpler substances. Elements are classified into different categories: -: Metals :- Metals Metals are those elements which have 1,2 or 3 valence electrons in their valence shell. Example : atomic no. of Na =11 Electronic confugration =2,8,1 They always loose electrons to form electropositive ions. Na – 1electron ------Na + :-  Non Metals :- Non-Metals -> Non metals are those elements which have 4,5,6 or 7 valence electrons in their valence shell and they always gain electrons to form electronegative ions. Cl(17) – 1 electron --------Cl- Electronic Configuration = 2,8,7 Video Explanation of Lesson Metals and Non-Metals II)  Physical Properties Of Metals and Non Metals 1. malleability: process of beating into thin sheets Metals :are malleable. Gold and silver is the most malleable metals. Malleability Non metals :non malle...

Acid-bases and salts * Preparation and uses of important compounds. I) Caustic Soda (Sodium Hydroxide, NaOH) Preparation of Sodium hydroxide Preparation: In the process of electrolytic decomposition of brine (aqueous solution of sodium chloride), brine decomposes to form sodium hydroxide. 2NaCl(aq) + 2H2O(l) → 2NaOH(aq) + Cl2(g) + H2(g) In this process, chlorine is moved towards anode and hydrogen gas is moved towards cathode as by products. This whole process is known as Chlor – Alkali process. Uses: Sodium hydroxide is used for degreasing of metals, manufacturing of paper, soap, detergents, artificial fibres, etc. II) Bleaching Powder (Calcium Oxychloride, CaOCl2) Preparation of Bleaching powder Preparation: Bleaching powder is produced by the action of chlorine on dry slaked lime [Ca(OH)2]. Ca(OH)2 + Cl2→ CaOCl2 + H2O Uses: (i) It is use for bleaching cotton and linen in the textile industry, for bleaching wood pulp in paper factories and for bleaching washed clothes in laundry; (i...

  • Importance of pH in everyday life :- --------------------------------------- I) Are plants and animals pH sensitive ?   -> Our body works within the pH range of 7.0 to 7.8 .  -> Organisms survive in this narrow pH range change.  -> When pH of rain water is less than 5.6 then it is called acid rain . It lowers the pH of river water when mix with it and the survival of aquatic life becomes difficult. II) pH of Soil :- pH of Soil   -> plants required a specific pH for their healthy growth.  -> In most plants, the optimum pH range is from 5.5 to 7.0 , but some plants will grow in more acid soil or may require a more alkaline level.   III) pH in our digestive system :- pH of digestive system   -> Our stomach produces hydrochloric acid which helps in the digestion of food without harming the stomach.   -> During indigestion stomach produces too much acid which causes pain and irritation . To get ride from thi...

 I) What happens to an Acid  in a Water Solution ? ->  The hydrogen ion produced in the presence of water in HCl. - >The separation of H+ ion from HCl molecules cannot occur in the absence of water.   HCl + H2O --------> H3O+  + Cl- - >Hydrogen ions cannot exist alone but exist after combines water molecules hence H+ (aq) or hydronium ion (H3O+) .   H+ + H2O --------> H3O+ II) What happens to an Base in a Water Solution ? - >Bases generate hydroxide (OH-) ions in water.  Bases which soluble in water are called alkalis .   Examples:-   a) NaOH(s) + H2O(l) --------> Na+(aq) + OH-(aq)  b) KOH(s) + H2O (l) ----------> K+ (aq) + OH- (aq)  c)  Mg(OH)2 (s) + H2O (l) ----------> Mg2+(aq) +2OH- (aq) III) Process of mixing of Acid or a Base with Water. - >The process of dissolving an acid or a base in water is a exothermic process .  - >We must take care when doing this process. Like mixing of c...

  I) Acids and Bases reacts with each other. - > When Acids reacts with Bases to form Salt and water as product. This reaction is also called as neutralisation reaction . Acid + Base ---------> Salt + Water  Example:- i) NaOH (aq) + HCl (aq) ---------> NaCl (aq) + H2O(l) ii) MgOH (aq) + HCl (aq) -------> Mg(OH)2 (aq) + H2O (l) iii) LiOH (aq) + HCl (aq) ---------> LiCl (aq) + H2O (l) iv) Ca(OH)2 (aq) + H2SO4 (aq) ---------> CaSO4 (aq) + H2O (l) II) Metallic Oxides reacts with Acids:- - > When Metallic Oxides reacts with Acids it gives Salt and Water as products. Metallic Oxide + Acid ------> Salt + Water Example :-  i)  CuO (s) + HCl (aq) -------> CuCl2 (aq) + H2O (aq) black colour                     blue-green colour ->We notice that tht the colour of the solution becomes blue-green due to the formation of copper(II) chloride in the reaction . ii) CuO (s) + H2SO4 (aq) -------> CuSO4 ...

                             • When Acids reacts with Metal.  ->  Acid + Metal ---------> Salt + Hydrogen gas. -> When Acids react with Metals it gives salt and liberate hydrogen gas. Example:- i) 2HCl (l)+ 2Na(s) ---------> 2NaCl(s)+ H2(g) ii) H2SO4 (l) + Mg (s) ----------> MgSO4(s) + H2 (g)  iii) 2CH3COOH (l) + 2Na(s) -------> 2CH3COONa (s) + H2 (g) • When Bases reacts with Metals: -> When bases reacts with metals it gives salt and Hydrogen gas . Base + Metal ---------> Salt + Hydrogen gas Example:-  I) 2NaOH (aq) + Zn (s) ----------> Na2ZnO2 (s) + H2 (s) II) NaOH (aq) + Al (s)  ----------> NaAlO2 + H2 (s) • Metal carbonate and metal hydrogen carbonate reacts with acids. -> When Metal carbonate/ Metal hydrogen carbonate reacts with acids to give Salt, Water and  releases Carbon dioxide gas. Metal carbonate/Metal hydrogen carbonate + Acid ------> ...