Saturday, September 1, 2012

Assignment Chemistry + Physics X Summative assessment-1

Assignment - class-X Chemistry   Summative assessment-1
1. Write the balanced chemical equations for the following reactions and identify the type of reaction in each case.
(a) Thermite reaction, iron (III) oxide reacts with aluminum and gives molten iron and aluminum oxide.
(b) Magnesium ribbon is burnt in an atmosphere of nitrogen gas to form solid magnesium nitride.
(c) Chlorine gas is passed in an aqueous potassium iodide solution to form potassium chloride solution and solid iodine.
(d) Ethanol is burnt in air to form carbon dioxide, water and releases heat.
2. Which among the following changes are exothermic or endothermic in nature?
(a) Decomposition of ferrous sulphate                (b) Dilution of sulphuric acid
(c) Dissolution of sodium hydroxide in water     (d) Dissolution of ammonium chloride in water
3. A solution of potassium chloride when mixed with silver nitrate solution, an insoluble white substance is formed. Write the chemical reaction involved and also mention the type of the chemical reaction?
4. Grapes hanging on the plant do not ferment but after being plucked from the plant can be fermented. Under what conditions do these grapes ferment? Is it a chemical or a physical change?
5. During the reaction of some metals with dilute hydrochloric acid, following observations were made.
(a) Silver metal does not show any change
(b) The temperature of the reaction mixture rises when aluminium (Al) is added.
(c) The reaction of sodium metal is found to be highly explosive
(d) Some bubbles of a gas are seen when lead (Pb) is reacted with the acid.
Explain these observations giving suitable reasons.
6. What will be the action of the following substances on litmus paper? Dry HCl gas, Moistened NH3 gas, Lemon juice, Carbonated soft drink, Curd, Soap solution.
7. A student prepared solutions of (i) an acid and (ii) a base in two separate beakers. She forgot to label the solutions and litmus paper is not available in the laboratory. Since both the solutions are colorless, how will she distinguish between the two?
8. How would you distinguish between baking powder and washing soda by heating?
9. Salt A commonly used in bakery products on heating gets converted into another salt B which itself is used for removal of hardness of water and a gas C is evolved. The gas C when passed  through lime water, turns it milky. Identify A, B and C.
10. A metal carbonate X on reacting with an acid gives a gas which when passed through a solution Y gives the carbonate back. On the other hand, a gas G that is obtained at anode during electrolysis of brine is passed on dry Y, it gives a compound Z, used for disinfecting drinking water. Identity X, Y, G and Z.
11. Write the balanced chemical equations for the following reactions and identify the type of reaction in each case.
(a) Thermit reaction, iron (III) oxide reacts with aluminium and gives molten iron and aluminium oxide.
(b) Magnesium ribbon is burnt in an atmosphere of nitrogen gas to form solid magnesium nitride.
(c) Chlorine gas is passed in an aqueous potassium iodide solution to form potassium chloride solution and solid iodine.
(d) Ethanol is burnt in air to form carbon dioxide, water and releases heat.
12. Which among the following changes are exothermic or endothermic in nature?
(a) Decomposition of ferrous sulphate               (b) Dilution of sulphuric acid
(c) Dissolution of sodium hydroxide in water (d) Dissolution of ammonium chloride in water
13. A solution of potassium chloride when mixed with silver nitrate solution, an insoluble white substance is formed. Write the chemical reaction involved and also mention the type of the chemical reaction?
14. Why do fire flies glow at night?
15. Which among the following are physical or chemical changes?
(a) Evaporation of petrol                              (b) Burning of Liquefied Petroleum Gas (LPG)
(c) Heating of an iron rod to red hot.           (d) Curdling of milk
(e) Sublimation of solid ammonium chloride
16. During the reaction of some metals with dilute hydrochloric acid, following observations were made.
Explain these observations giving suitable reasons.
(a) Silver metal does not show any change
(b) The temperature of the reaction mixture rises when aluminum (Al) is added.
(c) The reaction of sodium metal is found to be highly explosive
(d) Some bubbles of a gas are seen when lead (Pb) is reacted with the acid.
CLASS X – ASSIGNMENT SUBJECT – Physics
1. Fuel used in thermal power plants is
(a) water    (b) uranium             (c) biomass  (d) fossil fuels
2.Which of the following is a non-renewable source of energy?
(a) Wood (b) Sun        (c) Fossil fuels       (d) Wind
3.The strength of magnetic field inside a long current carrying straight solenoid is
(a) more at the ends than at the centre            (b) minimum in the middle
(c) same at all points                                             (d) found to increase from one end to the other
4. In an electrical circuit two resistors of 2 Ω and 4 Ω respectively are connected in series to a 6 V battery.    The heat dissipated by the 4 Ω resistor in 5 s will be (a) 5 J (b) 10 J (c) 20 J  (d) 30 J
5.What is the role of a plane mirror and a glass sheet in a solar cooker?
6. Mention three advantages of a solar cell?
7.How can solar energy be harnessed? Mention any two limitations in using solar energy. How are these limitations overcome?
8.What is biomass? Explain the principle and working of a biogas plant using a labelled schematic diagram.
9.What does the direction of thumb indicate in the right-hand thumb rule. In what way this rule is different from Fleming’s left-hand rule?
10.Draw an appropriate schematic diagram showing common domestic circuits and discuss the  importance of fuse. Why is it that a burnt out fuse should be replaced by another fuse of identical rating?
11. What is Joule’s heating effect? How can it be demonstrated experimentally? List its four applications in  daily life.
12. Find out the following in the electric circuit given in Figure
(a) Effective resistance of two 8 Ω resistors in the combination
(b) Current flowing through 4 Ω resistor
(c) Potential difference across 4 Ω resistance
(d) Power dissipated in 4 Ω resistor
(e) Difference in ammeter readings, if any.

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