CBSE Class 10 Science Collection Of Important Questions Worksheet

Q1. What is the chemical name of baking soda? Give formula also.

Q2. Why POP should be stored in a moisture proof container?

Q3. Name the largest artery in human body.

Q4. Name the metal which is least reactive and silvery white.

Q5. Sweet tooth leads to tooth decay. Explain. What is the role of tooth paste in tooth decay?

Q6. When water is added to a white powder ‘A’, vigorous reaction takes place and a large amount of heat is released. Compound A is also used in white washing. Identify A, Give its chemical reaction and name the product.

Q7. Why copper turns to green when left in open? Give chemical equation also.

Q8. Why ice cream vendor adds common salt to ice to make ice cream. State the reason by giving chemical equation.

Q9. What is a good source of energy? Give one example of good source of energy.

Q10. State two disadvantages of Hydro Power Plants?

Q11. Why is series arrangement not used for domestic circuits?

Q12. Why are coils of electric toasters and electric irons made of an alloy rather than a pure metal?

Q13. Discuss how brain and spinal cord is protected.

Q14. Predict the nature of following salts by hydrolysing them, and give chemical equations:

a) Sodium chloride.

b) Magnesium sulphate.

c) Potassium carbonate.

Q15. Name the acid found in the following:

a) Curd.

b) Bee’s sting.

c) Lemon juice.

Q16. The atomic number of F, Na and Ne are 9, 10 and 11.Why Na and F are very reactive and Ne shows almost no reactivity?

Q17. Draw a labelled diagram of a biogas plant and labell any three parts.

Q18. The SI unit of a Physical quantity is Ohm. Name the physical quantity. What are the two factors on which it depends?

Q19. i. Give the commercial unit of electrical energy. 

ii. An electric Iron of resistance 20 Ω takes a current of 5 A. Calculate the heat developed in 30 s.

Q20. State three factors on which magnetic field of a current carrying coil depends. 

Q21. Write the functions of the following in the digestive process:

i) HCl ii) Bile ii) Pancreatic amylase 

Q22. Name the two hormones secreted by pancreas. Write the function of each hormone named.

Q23. Give reasons for the following. 

i) Glottis is covered by epiglottis.

ii) Lung alveoli are covered with blood capillaries.

iii) The walls of trachea is supported by cartilage rings.

Q24. Give reasons for the following:

i) M.P. and B.P. of ionic compounds are high.

ii) Tarnished copper vessels are cleaned with tamarind juice.

iii) A sulphide ore is converted into its oxide to extract the metal.

iv) Galvanisation is the better method of prevention than painting.

v) Chips packets are flushed with nitrogen gas.

OR

Explain how the following metal is obtained from their compounds by the process of reduction:

a) Name the metal which is in the middle of the reactivity series of metals..

b) Give the name and formula of its ore.

c) Give the chemical reactions involved.and name them.

d) In the electrolytic refining of metal M, name the cathode, anode and electrolyte.

Q25. Draw the diagram of cross section of a leaf and labell the following in it :

i) Chloroplast ii) Guard cells iii) Lower epidermis iv) Upper epidermis

Name the two stages in photosynthesis

OR

What is reflex action? Give its two examples. Illustrate the pathway followed by a message from the receptor in a reflex arc.

Name any five receptors along with the organ in which they occur.

Q26. i. What is electric Power? Write the expressions for electric power. Define the SI unit of electric power.

ii. An electric motor takes 5A current from a 220 V line. Calculate the power. Also calculate the energy consumed in 2 hours.

(OR)

i. Derive the relation for the equivalent resistance of a combination of three resistors connected in Parallels.

Draw the necessary diagram

ii. Show how would you connect three resistors each of resistance 6 Ω so that the combination has a total resistance of 18 Ω.

Q27. Draw a diagram of a electric DC Generator to explain its construction and labell the following parts:

Armature coil, Magnetic poles, Split rings, Brushes and Battery. Give one difference between the construction of AC Generator and DC Generator . 

(OR)

i) What are the three factors on which force on a current carrying conductor placed in a magnetic field depends?

ii) State Fleming’s left hand Rule.

Q28. When a few drops of phenolphthalein are added to a dil. solution of HCl it remains colourless. What will be the colour of final mixture when excess of NaOH is added to it :

a) Red. c) Green.

b) Pink. d) Blue.

Q29. A student adds dil. solution of hydrochloric acid to universal indicator. He would observe that colour of the solution changes from colourless to :

a) Red. c) Green.

b) Blue. d) Yellow.

Q30. Two solutions A and B were found to have pH value of 8 and 3 respectively. The inference which can be drawn is :