Wednesday, March 27, 2013

10th Metal and Non Metal [CBSE Test Paper]


QUESTIONS FROM CBSE EXAMINATION PAPERS

I. VERY SHORT ANSWER QUESTIONS (1 Mark)

1. Why do silver ornaments loose their shine when kept for some time? [2010 (T-1)]

2. Name a metal other than aluminium that is covered with an oxide film layer. [2010 (T-1)]

3. Name one metal and one non-metal which exists in liquid state at room temperature? [2010 (T-1)]

4. Name a non-metal which is lustrous and a metal which is non-lustrous. [2010 (T-1)]

5. Name two metals which have very low melting point. [2010 (T-1)]

6. If copper metal is heated over a flame, it develops a coating. What is the colour and composition of this coating? [2010 (T-1)]

7. Why is sodium metal kept immersed in kerosene oil? [2010 (T-1)]

8. Name one metal which react with very dilute HNO3 to evolve hydrogen gas. [2010 (T-1)]

9. A non-metal X exists in two different forms Y and Z. Y is the hardest natural substance, whereas Z is a good conductor of electricity. Identify X, Y, and Z. [2010 (T-1)]

10. An element A form two oxides AO and AO2. The oxide AO is neutral whereas the oxide AO2 is acidic in nature. Would you call element A a metal or non-metal. [2010 (T-1)]

II. SHORT ANSWER QUESTIONS (2/3 Marks)

11. What are the constituents of solder alloy? Which property of solder makes it suitable for welding electrical wires? [HOTS]

12. What happen when (a) ZnCO3 is heated in the absence of oxygen? (b) a mixture of Cu2O and Cu2S is heated?[HOTS]


13. A metal P is placed in an aqueous solution of Q. In a few hours metal Q was deposited on metal P. Which metal amongst P and Q is more reactive and why? [HOTS]

14. State reasons for the following observations:

(i) The shining surface of some metals becomes dull when exposed to air for a long time.

(ii) Metals sulphides occur mainly in rocks but metal halides occur mostly in sea and lake. [2009]

15. Differentiate between roasting and calcinations processes used in metallurgy. Give an example of each. [2008]

16. Give reason for the following:

(a) Gold and silver are used to make jewellery.

(b) Carbonate and sulphide ores are usually converted into oxides prior to reduction during the process of extraction. [2008]

17. Compound X and aluminium are used to join railway tracks. [HOTS]

(a) Identity the compound X (b) Name the reaction (c) Write down its reaction.

18. Give the steps involved in the extraction of metals of low and medium reactivity from their respective sulphide ores. [HOTS]

19. (a) What type of reaction is to be performed to ascertain and verify the position of metals in the reactivity series?

(b) If an iron nail immersed in the aqueous solution of copper sulphate, what are the changes happening to the nail and to the solution?


(c) Write the balanced chemical equation for the reaction between iron metal and aqueous copper sulphate solution. [2010 (T-1)]


20. Name two metals which react violently with cold water. Write any three observations you would make when such a metal is dropped into water. How would you identify the gas evolved, if any, during the reaction? [2008]

For solutions and more practice and solved paper: visit Link

Wednesday, March 6, 2013

Ch.1- Matter in our surroundings 9th Solved Question

Picture
Q.1 Define matter.

Ans: Anything that occupies space and has mass and is felt by senses is called matter.

Q.2 what happens if you put copper sulphate crystals in water?

Ans: Copper sulphate crystals mixed between the spaces of molecules of water and disappear.

Q.3 A substance has a definite volume but no definite shape? State whether this substance is a solid, a liquid or a gas.



Ans: Liguid

Q.4 Arrange the following substances in increasing order of force of attraction between the particles. 
(a) Milk (b) Salt (c) Oxygen.

Ans: Oxygen < Milk< Salt

Q.5 A substance has neither a fixed shape nor a fixed volume . State whether it is a solid , a liquid or a gas.

Ans: Gas

Q.6 The melting point of a substance is below the room temperature. Predict its physical state.

Ans: Ice

Q.7 What is vapour ?

Ans: A substance that found in gaseous state only at room temperature is called Vapour

Q.8 Name the temperature at which the solid and liquid states of substance can exist together.

Ans; 0 degree C

Q.9 What is the effect of pressure on boiling point?

Ans: boiling point  increases with  increase in pressure.

Q.10 Name any two substances which sublime.

Ans: Camphor and Naphthalene, iodine and Ammonium chloride iodine

Q.11 Define Condensation.

Ans: The change of solid state from liquid state on cooling is also known as Condensation.

Q.12 For any substance, why does the temperature remain constant during the change of state?

Ans: On increasing the temperature of solids, the kinetic energy of the particles increases which is used to overcome the forces of attraction between the particles therefore the temperature remain constant during the change of state.

Q.13 Which is the slow process , Evaporation or Boiling ?

Ans: Evaporation

Q.14 State the effect of surface area on rate of evaporation.

Ans: If the surface area is increased, the rate of evaporation increases.

Q.15 Why are we able to sip hot tea faster from saucer rather than from a cup?

Ans: This is because the rate of evaporation is faster from saucer.

Q.16 What is the SI unit of temperature?

Ans: Kelvin

Q.17 Kelvin scale of temperature is regarded as better scale than Celsius. Why?

Ans: As it has wide range of measurement and Kelvin scale of temperature has always positive sign , hence regarded as better scale than Celsius.

Q.18.  Convert 10oC into Kelvin scale.

Ans: 270 + 10 = 280 K

Q.19 Pressure on the surface of a gas is increased. What will happen to the inter particle forces?

Ans: come closer and compressed

Q.20 A gas can exert pressure on the walls of the container. Assign reason.

Saturday, March 2, 2013

CBSE Board Paper Solution : 2013 Class X

Now U can See 

Solution of board paper 2014 maths class 10 CBSE

Class X Delhi Math Set-3 Section – A [2013]
1. The angle of depression of a car, standing on the ground, from the top of a 75 m high tower, is 30°. The distance of  the car from the base of the tower (in m.) is:

(A) 25 √3 (B) 50√ 3 (C) 75√ 3 (D) 150 

Answer: (C)

2. The probability of getting an even number, when a die is thrown once, is:

(A) ½ (B) 1/3 (C) 1/6 (D)5/6 

Answer: (A)

3. A box contains 90 discs, numbered from 1 to 90. If one disc is drawn at random from the box, the probability that it bears a prime-number less than 23, is :

(A) 7/ 90 (B) 10/ 90 (C) 4/ 45 (D) 9/ 89

 Answer: (C)
For full paper solution to check out your answer Visit given link

Question Papers for Board Examinations 2011 (CLASS X)

Mathematics SET-1    SET-2     SET-3    SET-4     SET-5

Science        SET-1     SET2     SET3      SET4      SET-5