X CHEM PRACTICE PAPER SA I

1. Potato Chips manufactures fill the packet of chips with nitrogen gas. Why ?

2. An element A forms 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 a non-metal.

3. A small amount of ferrous sulphate were heated in a hard glass test tube?

(i) Write the equations involved in the above reaction

(ii) What type of reaction is taking place ?

4. What is a redox reaction? Write down a chemical equation representing it.

7. A metal is treated with dil H₂S0₄ the gas evolved is collected by the method shown in the figure. Answer the following

(i) Name the gas. (ii) Name the method of collection of the gas. (iii) Is the gas soluble or insoluble in water? (iv) Is the gas lighter or heavier than air ?

5. Differentiate between roasting and calcination process giving an example of each.

6. A brown substance ‘X’ on heating in air forms a substance ‘Y’. When hydrogen gas is passed over heated ‘Y’, it again changes back into ‘X’.

(i) Name the substance X and Y.

(ii) Name the chemical processes occurring during both the changes.

(iii) Write the chemical equations.

7. What is neutralisation reaction ? Give two examples.

8. A compound which is prepared from Gypsum has the property of hardening when mixed with proper quantity of water.

(i) Identify the Compound.

(ii) Write the chemical equation for its preparation.

(iii) Mention one important use of this compound.

9. Four metals A,B,C and D are in turn added to the following solutions one by one. The observations made are tabulated below.

Metal Iron (II) sulphate Copper (II) Sulphate Zinc sulphate Silver nitrate

A No reaction Displacement

B Displacement No reaction

C No reaction No reaction No reaction Displacement

D No reaction No reaction No reaction No reaction

Answer the following questions based on the above information.

(i) Which is the most active metal and why ?

(ii) What would be observed if B is added to a solution of copper sulphate and why.

(iii) Arrange the metals A,B,C and D in order of increasing reactivity.

(iv) Container of which metal can be used to store both Zinc sulphate solution and silver nitrate solution.

(v) Which of the above solutions can be easily stored in a container made up of any of these metals.

OR

Design an activity to show the conditions needed for iron nails to rust. Why do we apply paint on iron articles ?

10. Reddish brown deposit obtained on iron nails when kept in a solution of CuSO₄ in water is that of

(a) Cu₂O (b) CuO (c) Cu (d) CuS

11. When crystals of FeSO₄ are strongly heated the residue obtained is :

(a) red in colour (b) blue in colour

(c) green in colour (d) colourless.

12. When CO₂ is passed through lime water, milkiness is formed is due to :

(a) CaCO₃ (b) Ca(OH)₂

(c) Ca(HCO₃)₂ (d) none of these

13. In a sample of distilled water a pinch of solid sodium carbonate is dissolved in it. The pH will be:

(a) Less than 7 (b) More than 7 (c) Exactly 7 (d) very near to 7

14. A few drops of liquid ‘X’ were added to distilled water. It was observed that pH of the water is increased. The liquid ‘X’ is:

(a) lemon juice (b) NaCl solution

(c) Na₂CO₃ solution (d) dilute HCl solution

MIDPOINT OF RIGHT ANGLE TRIANGLE

In the figure given below, ABC is a right angled triangle with ÐABC = 90° is

the midpoint of AC. Prove that DA=DC=DB

LINK FOR CBSE SAMPLE PAPER

http://www.cbse.nic.in/welcome.htm

X SCIENCE PROBABLE QUESTIONS SA II -1

1. Draw a ray diagram to determine the position of image formed of an object placed between the pole and the focus of concave mirror. [1]

2. The power of a lens is +5.5D. What is the focal length and nature of this lens? [11

3. A 14 years old student is not able to see clearly the questions written on a blackboard placed at a distance of 5m from him.

(i) Name the defect of vision, he is suffering from,

(ii) Name the type of lens used to correct this defect. [1]

4. What change in colour is observed when white silver chloride is left exposed to sunlight? What type of chemical reaction is this? [1]

5. A compound ‘X’ is an important ingredient of an antacid. It is also used in fire extinguisher. Identify ‘X’ & write its chemical formula? [11

6. Giving an example to explain thermit reaction. [1]

7. A student performs an experiment to study the magnetic effect of current around a current carrying straight conductor. He reports that,

(i) the direction of deflection of the north pole of a compass needle kept at a given point near the conductor remains unaffected even when the terminals of the battery sending current in the wire are inter changed.

(ii) for a given battery, the degree of deflection of a N-pole decreases when the compass is kept at a point farther away from conductor. Which of the above obseivations of the student is incorrect? Why? [2]

8. What will be observed when the screen is placed,

(i) between the two inverted prism, and

(ii) after the second inverted prism as shown in the figure?

(ii) what will happen if the prism is hollow? [2]

X MATHS PROBABLE QUESTIONS SA II -2

1. (a)The ratio of the base radii of two right circular cones of the same height is 3 : 4. Find the ratio of their volumes.9:16

(b) The ratio of the heights of two right circular cones is 5 : 2 and that of their base radii in 2:5. Find the ratio of their volumes. Ans2:5

(c) The height and the radius of the base of a right circular cone is half the corresponding height and radius of another bigger cone. Find :(i) the ratio of their volumes. (ii) the ratio of their lateral surface areas. Ans 1:8 , 1:4

2. An open cylindrical vessel is made of a metal. The internal diameter is 7 cm, the internal depth is 10 cm and the metal is 5 mm thick. Calculate

(i) the capacity of the vessel (ii) the volume of the metal. Ans: 385,143

X MATHS PROBABLE QUESTIONS SA II -1

1. Two customers are visiting a particular shop in the same week (Monday to Saturday). Each is equally likely to visit the shop on any day of the week. What is the probability that both will visit the shop on(i) the same day? (ii) two different days? (iii) consecutive days?
2. A canal is 300cm wide and 120cm deep. The water in the canal is flowing with a speed of 20km/h. How much area will it irrigate in 20 minutes if 8cm of standing water is desired?
3. Solve for x, using the quadratic formula: abx² - (a²+b²)x + ab=0
4. Marbles of diameter 1.4 cm are dropped into a cylindrical beaker of diameter 7 cm, containing some water. Find the number of marbles that should be dropped into the beaker so that the level rises by 5.6 cm.
5. How many metres of cloth 5 m wide will be required to make a conical tent, the radius of whose base is 7 m and whose height is 24 cm?
6. A hollow cone is cut by a plane parallel to the base and upper portion is removed. If the curved surface area of the remainder is 8/9 of the curved surface area of the whole cone, find the ratio of the line segments into which the altitude of the cone is divided by the plane.

X MATHS SAMPLE PAPER SA II -1

1. Two circles touch each other externally at C and AB is a common tangent to the circles. Then, angle ACB=

(a) 60 ^o (b) 45 ^o (c) 30 ^o (d) 90^o

2. The length of an arc that subtends an angle of 24o at the centre of a circle with 5 cm radius is

(a) 2π /3 (b) 3π / 2 (c) π /3 (d) 5π /3

3. An observer 1.5 m tall is 28.5 m away from a tower. The angle of elevation of the top of the tower from his eyes is 450. The height of the tower is

(a) 10 m (b) 20 m (c) 30 m (d) 40 m

4. The probability that a randomly chosen number from one to twelve is a divisor of twelve is

(a) 1/12 (b) 1/2 (c) 1/4 (d) 1/6

5. The value of x, for which the points (x,-1), (2,1) and (4,5) lie on a line is

(a) 0 (b) 1 (c) 2 (d) 3

6. The ratio in which the point R (-2/7, -20/7) divides the join of P(-2,-2) and Q(2,-4) is

The Eminence

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