General knowledge with CBSE SCIENCE

  4. Unsolved question.. Previous One:- Mention the type of chemical reaction that takes place when: (i) a magnesium ribbon is burnt in air.- Combination Reaction (ii) limestone is heated.- Thermal decomposition (iii) silver bromide is exposed to sunlight.- Photo Decomposition (iv) electricity is passed through acidified water.- Electric Decomposition (v) ammonia and hydrogen chloride are mixed with each other.- Combination Write the chemical equation for each reaction Complete Answers: i) Combination reaction:  2 M g + O 2 ​ → 2 M g O ii) Thermal Decomposition reaction:  C a C O 3 ​ → C a O + C O 2 ​ iii) Photo Decomposition reaction:  2 A g B r → 2 A g + B r 2 ​ iv) Electric Decomposition reaction:  2 H 2 ​ O → 2 H 2 ​ + O 2 ​ v) Combination reaction:  N H 3 ​ + H C l → N H 4 ​ C l https://kumarashwanisspace.quora.com/?invite_code=mJAm7EsHIbguzQC3373T

  Important Points  👀 Metallurgy is defined as  a process that is used for the extraction of metals in their pure form.    👀 The compounds of metals mixed with soil, limestone, sand, and rocks are known as minerals. 👀 Metals are commercially extracted from minerals at low cost and minimum effort. These minerals are known as ores.     👀 The concentration of ores:      👀 Concentration is when we remove the unwanted materials like sand, dust, etc.                from  the ores, so we get concentrated ore full of our required metals.  Roasting : In this process, the ore is warmed in a continuous air supply in the furnace at any temperature lower than their melting point. Eg: 2ZnS + 3O2 → 2ZnO + 2SO2 ( During Sulphide ore Roasting will be there) Calcination : Calcination involves heating when the volatile matter escapes leaving behind the metal oxide.  E.g: ZnCO3 (s)  →...

 

Law of inheritance( Mendel's  law) First law of inheritance -   Mendel's law of dominance states that:  “ When parents with pure, contrasting traits are crossed together, only one form of trait appears in the next generation" .  The hybrid offsprings will exhibit only the dominant trait in the phenotype.”  Law of dominance is known as the first law of inheritance. Second law of inheritance- Law of segregation is the second law of inheritance.  "Law of segregation states that the pair of alleles segregates from each other during meiosis (gamete formation) so that only one factor will be present in each gamete".   Third law of inheritance:- The Law of Independent Assortment states that  "during a dihybrid cross (crossing of two pairs of traits), an assortment of each pair of traits is independent of the other" .  In other words, during gamete formation, one pair of trait segregates from another pair of traits independently. https://kumarashwani...

 Acid-Base and Salt  1. How is concentration of hydronium ions (H3O+) affected when a solution of acid isdiluted? Ans. The concentration of hydronium ions decreased when the solution of an acid is diluted. 2.  What effect does the concentration of H+ ions have on the nature of the solution? Ans. Higher the concentration of H+ ions, greater is the acidic nature of the solution. 3.   Name the substance which on treatment with chlorine yields bleaching powder. Ans. Slaked lime or calcium hydroxide. 4. What is the common name of the compound CaOCl2? Ans. Bleaching powder. 5.   Name the sodium compound which is used for softening hard water  Ans. Sodium carbonate is used for softening hard water.

  Chemical Reaction And Chemical Equation 1.  A compound ‘A’ is used in the manufacture of cement. When dissolved in water, it evolves a large amount of heat and forms compound ‘B’. (i) Identify A and B. (ii) Write chemical equation for the reaction of A with water. (iii) List two types of reaction in which this reaction may be classified. (2020) Answer: (i) A is calcium oxide, CaO which is used in the manufacturing of cement. B is calcium hydroxide Ca(OH) 3 . (iii) The given reaction is a combination reaction. Example : NH 3(g) (g) + HCl (g)  → NH 4 Cl (s) 2. Mention with reason the colour changes observe when: (i) silver chloride is exposed to sunlight. (ii) copper powder is strongly heated in the presence of oxygen. (iii) a piece of zinc is dropped in copper sulphate solution. Ans:  (i) When white silver chloride is left exposed to sunlight, its colour changes to grey as it decomposes to silver in the presence of sunlight. This type of reaction is called photodeco...

  Chemical Reaction and Equations Q1. What is the meaning of chemical reaction? Ans: It is a process which transforms one or more substances into new substances with new properties. Q2. What is chemical equations? Ans: A chemical equation is a statement used in chemistry to represent a chemical reaction. Q3. What are reactants? Ans: The substances which take part in a chemical reaction are called reactants. Q4. What are products? Ans: The substance which are formed as a result of chemical reactions are called products. Q5. What is the meaning of balanced chemical equation? Ans: The chemical equation in which total number of atoms of reactants is equal to the total number of atoms of products is known as 'Balanced Chemical Equation'. Q6. What is skeletal equation? Ans: A chemical equation in which the number of atoms of each kind are not equal in the reactants and products is called unbalanced chemical equation or skeletal equation. Q7. What method we can use to balanced chemica...