CBSE Important Questions

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

Q. 2. What is solubility. Give its units.(1)

Q. 3. Why is Crystallization considered better than simple evaporation.(1)

Q. 4. What is latent heat of vaporization.

Q. 5. Convert the following into K scale and 0C respectively :

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

Q. 6. 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. 7.

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

Q. 9. 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)