(Important Questions) CBSE Important Questions For Chemistry Class IX

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CBSE Important Questions For Science Class IX

 

Q. 1. Write the chemical formula of (a) calcium nitrate (b) ferric oxide?

Q. 2. Write electronic configuration of fluorine and potassium.

Q. 3. Write the names of Mg(HCO3)2 and Ba3(PO4)2.

Q. 4. What are cathode rays?

Q. 5. Calculate the maximum no. of electrons that can be present in the 3rd orbit of an atom?

Q. 6. Why are He, Ne and Ar called inert gases?

Q. 7. A naturally occurring sample of lithium contains 7.42% of 6Li and 92.58% of 7Li. Calculate the atomic mass of a naturally occurring sample of lithium.

Q. 8. Define atomicity? What are diatomic molecules? Give two examples.

Q. 9. What are isotopes? Give one example. Write two applications of isotopes.

Q. 10. The molecular mass of H2SO4 is 98 u. Calculate the number of moles of each element in 294 g of H2SO4.

Q. 11.

  1. What is the mass of 10 moles of Na2SO3?
  2. How many moles of Cr are there in 85g of Cr2S3? (Cr = 52)

Q. 12. Describe Rutherford’s α-ray scattering experiment and mention observations and conclusions derived from it. Cite one main defect of the Rutherford’s atomic model.

Q. 13. Give one example of emulsion and foam.(1)

Q.14. What is solubility. Give its units.(1)

Q. 15. Why is Crystallization considered better than simple evaporation.(1)

Q. 16. What is latent heat of vaporization.

Q. 17. Convert the following into K scale and 0C respectively :

  1. 300C
  2. 293 K.(1+1=2)

Q. 18. Give reasons for :

  1. Clothes dry faster on a windy day.
  2. Our palm feels cold when we put some acetone on it.(1+1=2)

Q. 19.

  1. Calculate the concentration of solution containing 40 g of salt in 360 g of water.
  2. Differentiate between:

    (1)solution and suspension
    (2)boiling and evaporation(1+1+1=3)

Q 20.

    a.    Draw a neat labeled diagram of how will you separate two miscible liquids having boiling point difference less than 25 K.(3).

    b.    Explain with an activity how will you obtain different colours of black dye. Also write the principle and draw a neat labeled diagram of the process.(2+1=3)

 

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