Class 10 Periodic Classification of Elements Important Questions

Periodic Classification of Elements Important Questions “Atomic number of an element is considered to be a more appropriate parameter than its atomic mass for a chemist.” Take the example of element X (atomic number 13) to justify this statement. How many triads did Dobereiner identify from the existing elements during his time ? Give an […]

Class 10 Periodic Classification of Elements Notes

Periodic Classification of Elements Notes Döbereiner’s triads:- Dobereiner arranged elements with similar properties into groups having three elements each and called those groups triads.When the three elements in a triad were written in the order of increasing atomic masses, the atomic mass of middle element was roughly equal to the average atomic masses of other […]

Class 9 Atoms and Molecules Notes

Atoms and Molecules Notes Laws of chemical combination:- Law of conservation of mass:- It states that mass can neither be created nor be destroyed in a chemical reaction. Or,It states that the total mass of reactants is equal to total mass of products in a chemical reaction. Law of constant proportion:- It states that in […]

Class 10 Carbon and its Compounds Previous Years Questions

Carbon and its Compounds Previous Years Questions To prepare soap fat/oil is heated with : ester acid alkali alcohol [CBSE 2017] [1 Mark] Four students recorded the following observation while adding soap in soft water and hard water. Soaps form lather easily in soft water as well as in hard water. Soaps form lather easily […]

Class 10 Carbon and its Compounds Important Questions

Carbon and its Compounds Important Questions a. Complete the following equations:-b. Write the name of the following:-i. CH3CH2COOHii. CH3CH2Brc. Draw the electron dot structure of ethene (C2H4). a. Name the compound CH3CH2OH and identity its functional group.b. Give a chemical test to distinguish between ethanol and ethanoic acid.c. Name the product formed when an organic […]

Class 10 Carbon and its Compounds Notes

Carbon And Its Compounds – Notes Covalent compound:- The compound formed by the sharing of electrons between the atoms is known as covalent compound. Difference between covalent compound and ionic/electrovalent compounds:- No. Covalent compounds Ionic/Electrovalent compounds (i) Covalent compounds are formed by the sharing of electrons between atoms. Ionic compounds are formed by the transfer […]

Class 10 Metals and Non-metals Important Questions

Metal and Non-Metals Important Questions In what forms are metals found in nature? With the help of examples explain how metals react with oxygen, water and dilute acids. Also write chemical equations for the reactions. How is copper obtained from its ore (Cu2S)? Write only the chemical equations. How is copper thus obtained refined? Name […]

Class 10 Metals and Non-Metals Previous Years Questions

Metals And Non-Metals : Previous Years Questions Show the formation of Na2O by the transfer of electrons. [CBSE 2019] [2 Marks] Show the formation of magnesium oxide by the transfer of electrons. [CBSE 2019] [2 Marks] What are ionic compounds ? Why do ionic compounds not conduct electricity in the solid state? [CBSE 2019] [2 […]

Class 10 Metals and Non-metals Notes

Metals and Non-metals Notes Physical properties of metals:- They are solid in state except mercury (liquid). They are malleable i.e., they can be beaten into thin sheet.Gold and silver are most malleable metals. They are ductile i.e., they can be drawn into thin wire.Gold is the most ductile metal. They are good conductors of heat […]

Class 10 Acids, Bases and Salts Previous Years Questions

Acids, Bases and Salts Previous Years Questions If 10 ml of H2SO4 is mixed with 10 ml of Mg(OH)2 of the same concentration, the resultant solution will give the following colour with universal indicator: [1 Mark] [CBSE 2020] Red Yellow Green Blue 2 mL of sodium hydroxide is added to a few pieces of granulated […]