Sample paper Science Class 10 ( Chemical reaction and equation, Reproduction, Electricity, preodic table, acid base and salt)

 

1. 2 mL of sodium hydroxide solution is added to a few pieces of granulated zinc metal taken in a test tube. When the contents are warmed, a gas evolves which is bubbled through a soap solution before testing. Write the equation of the chemical reaction involved and the test to detect the gas. Name the gas which will be evolved when the same metal reacts with dilute solution of a strong acid. (3 Marks)
2. Write one main difference between asexual and sexual mode of reproduction. Which species is likely to have comparatively better chances of survival – the one reproducing asexually or the one reproducing sexually ? Give reason to justify your answer. ( 3 Marks)
3. Show how would you join three resistors, each of resistance 9 W  so that the equivalent resistance of  of the combination is (i) 13.5 W  and (ii) 6 W (3 Marks)
4. (a) Write Joule’s law of heating.
    (b) Two lamps, one rated 100 W; 220 V, and the other 60 W; 220 V, are connected in parallel to
          electric mains supply. Find the current drawn by two bulbs from the line, if the supply voltage is
           220 V. (3Marks)
5. (a) List the factors on which the resistance of a conductor in the shape of a wire depends.
    (b) Why are metals good conductors of electricity whereas glass is a bad conductor of electricity? Give reason.
    (c) Why are alloys commonly used in electrical heating devices? Give reason. ( 3 Marks)
6. (a) The modern periodic table has been evolved through the early attempts of Dobereiner, Newland and
           Mendeleev. List one advantage and one limitation of all the three attempts.
    (b) Name the scientist who first of all showed that atomic number of an element is a more fundamental
          property than its atomic mass.
    (c) State Modern periodic law. ( 5 Marks)
7. (a) Define excretion.
    (b) Name the basic filtration unit present in the kidney. (c) Draw excretory system in human beings and label
          the following organs of excretory system which perform following functions :
        (i) form urine. (ii) is a long tube which collects urine from kidney. (iii) store urine until it is passed out. ( 5 Marks)
8. In an industrial process used for the manufacture of sodium hydroxide, a gas ‘A’ is formed as a by-product. The gas
    ‘A’ reacts with lime water to give a compound ‘B’ which is used as a bleaching agent in the chemical industry. Identify
    ‘A’ and ‘B’. Also give the chemical equations of the reactions involved ( 3 Marks)
9.  Carbon a member of group 14, forms a large number of carbon compounds estimated to be about three million.
     Why is this property not exhibited by other elements of this group? Explain. ( 3 Marks)
10. Draw a neat diagram showing fertilisation in a flower and label (a) Pollen tube, (b) Male germ cell and (c) Female germ cell, on it. Explain the process of fertilisation in a flower. What happens to the (i) ovary and (ii) ovule after fertilisation ?  ( 5 Marks)
11. (a) What is puberty ?
       (b) Describe in brief the functions of the following parts in the human male reproductive system : (i) Testes (ii) 

 Seminal vesicle (iii) Vas deferens (iv) Urethra
       (c) State how sperms move towards the female germ cell. (4 Marks)