D. C. Pant 💻

Chapter – 2 Is Matter Around Us Pure     Question 1. Which separation techniques will you apply for the separation of the following?   (a) Sodium chloride from its solution in water. -------Evaporation.   (b) Ammonium chloride from a mixture containing sodium chloride and ammonium chloride. -------Sublimation   (c) Small pieces of metal in the engine oil of a car. ------Filtration   (d) Different pigments from an extract of flower petals. -------Chromatography     (e) Butter from curd. ------------Centrifugation   (f) Oil from water. ---------Separating Funnrl   (g) Tea leaves from tea. ---------Filtration   (h) Iron pins from sand. -------------Magnetic Separation   (i) Wheat grains from husk. ------------ Sieving   (j) Fine mud particles suspended in water. --------- sedimentation and then filtration.     Question 2. Write the step...

  NCERT BOOK QUESTIONS AND EXERCISES Chapter 1 : Matter in Our Surroundings Part – 3  Question 1- Convert the following temperature to the Celsius scale :            (a)                       293 K              (b) 470 K  Answer – (a) Temp. On Kelvin scale = Temp. on Celsius scale + 273 293 = temperature on Celsius scale + 273 So, temperature on Celsius scale = 293 – 27       = 20 o C (b) Temp. On Kelvin scale = Temp. on Celsius scale + 273 470 = temperature on Celsius scale + 273 So, temperature on Celsius scale = 470 – 273         = 197 o C   Question 2 – Convert the following temperature to the Kelvin scale -        (a)                 ...

  NCERT BOOK QUESTIONS AND EXERCISES Chapter 1 : Matter in Our Surroundings Part – 2 Question 9 . Convert to following temperature to Celsius scale : (a)            300 K                          (b)     573 K Answer : (a) We know that : Temperature on Celsius   scale = temperature on Kelvin   scale – 273                                         = 300 – 273                                       ...

Class – 8 Subject – Science Chapter – 2 : Microorganisms : Friends and Foe Exercise    (Question and Answer)   Question 1. Fill in the blanks. (a) Microorganisms can be  seen with the help of a _ microscope _. (b) Blue green algae  fix _ nitrogen _ directly from air and enhance fertility of soil. (c) Alcohol is produced with the help of _ yeast _. (d) Cholera is  caused by _ bacteria _.   Question 2. Tick the correct answer. (a) Yeast  is used in the production of (i) sugar                                    (ii) alcohol  (iii) hydrochloric acid           (iv) oxygen   Answer - (ii) Yeast   (b) The following is an  antibiotic (i) Sodium bicarbonate.   (ii) Streptomycin (iii) Alcohol.                     ...