#### Term I - Model Question Paper

11th Standard

Reg.No. :
•
•
•
•
•
•

Chemistry

Time : 03:00:00 Hrs
Total Marks : 100

Part A

Multiple Choice Question

20 x 1 = 20
1. 40 ml of methane is completely burnt using 80 ml of oxygen at room temperature The volume of gas left. after cooling to room temperature is

(a)

40 ml CO2 gas

(b)

40 ml CO2 gas and 80 ml H2O gas

(c)

60 ml CO2 gas and 60 ml H2O gas

(d)

120 ml CO2 gas

2. An element X has the following isotopic Composition 200X = 90%, 199X = 8% and 202X = 2% The Weighted average atomic mass of the element X is closet to

(a)

201 u

(b)

202 u

(c)

199 u

(d)

200 u

3. The number of water molecules in a drop of water weighing 0.018 g is

(a)

6.022 x 1026

(b)

6.022 x1023

(c)

6.022 x 1020

(d)

9.9 x 1022

4. Which one of the following represents 180g of water?

(a)

5 Moles of water

(b)

90 moles of water

(c)

$\frac { 6.022\times { 10 }^{ 23 } }{ 180 }$ molecules of water

(d)

6.022 x 1024molecules of water

5. The oxidation number of Cr in Cr2O72- __________ is

(a)

+6

(b)

-6

(c)

+7

(d)

-7

6. Which of the following contain same number of carbon atoms as in 6 g of carbon-12.

(a)

7.5 g ethane

(b)

8 g methane

(c)

both (a) and (b)

(d)

none of these

7. Which of the following compound(s) has /have a percentage of carbon same as that in ethylene (C2H4)

(a)

propene

(b)

ethyne

(c)

benzene

(d)

ethane

8. The change in the oxidation number of S in H2S and SO2,in the following industrial reaction:
2H2S(g) + SO2(g) $\longrightarrow$ 3S(s) + H2O(g)

(a)

-2 to 0, +4 to 0

(b)

-2 to 0, +4 to -1

(c)

-2 to -1, +4 to 0

(d)

-2 to -1, +4 to -2

9. In which of the following reactions, hydrogen peroxide acts as an oxidising agent?

(a)

I2+ H2O2 + 20H- $\longrightarrow$ 21- + 2H2O + O2

(b)

PbS + 4H2O2 $\longrightarrow$ PbSO4 + 4H2O

(c)

2MnO4-+ 3H2O2 $\longrightarrow$ 2MnO2 + 3O2 + 2H2O + 2OH-

(d)

HOCI + H2O2 $\longrightarrow$ H2O+ + Cl- + O2

10. A sample of ${ CaCO }_{ 3 }$ is 50% pure.  On heating 1.12 L of ${ CO }_{ 2 }$ ( at STP) is obtained.  Residue left (assuming non volatile Impurity is

(a)

7.8g

(b)

3.8g

(c)

2.8g

(d)

8.9g

11. Polyethylene can be produced from calcium carbide according to the following sequence of relations.

${ CaC }_{ 2 }+{ H }_{ 2 }O\rightarrow CaO+HC\equiv CH$

$n(HC\equiv CH)+{ nH }_{ 2 }\rightarrow { \left( { CH }_{ 2 }-{ CH }_{ 2 } \right) }_{ n }$

The mass of polyethylene, which can be produced from 20.0 kg of ${ CaC }_{ 2 }$ is

(a)

6.75 kg

(b)

7.75 kg

(c)

8.75 kg

(d)

9.57 kg

12. 1.0g of magnesium is burnt with 0.56g${ O }_{ 2 }$ in a closed vessel.  Which reactant is left in excess and how much? (At.wt.Mg=24; 0=16)

(a)

Mg. 0.16g

(b)

${ O }_{ 2 },0.16\quad g$

(c)

Mg,0.44 g

(d)

${ O }_{ 2 },0.28\quad g$

13. ${ 10 }^{ 21 }$ molecules are removed from 200 mg of ${ CO }_{ 2 }$.  The moles of ${ CO }_{ 2 }$ left are

(a)

$2.88\times { 10 }^{ -3 }$

(b)

$28.8\times { 10 }^{ -3 }$

(c)

$288\times { 10 }^{ -3 }$

(d)

$28.8\times { 10 }^{ -3 }$

14. 1+2 (17-15.1)=x. Hence, x is equal to

(a)

4.8

(b)

19.9

(c)

5

(d)

5.0

15. Number of significant figures in the answer of the following will be $\frac { (29.2-20.2)(1.79\times 105) }{ 1.39 }$

(a)

4

(b)

3

(c)

2

(d)

1

16. H2SO4 solution is 500 molal (d=1.8 g/mL) hence, its molarity is

(a)

18 M

(b)

36 M

(c)

9 M

(d)

4.50 M

17. Molality of sucrose solution changes if

(a)

temperature is increased

(b)

(c)

in both (a) and (b) cases

(d)

in none of the above cases

18. Equal moles of H2O and NaCI are present in a solution. Hence, molality of NaCI solution is

(a)

0.55

(b)

55.5

(c)

1.00

(d)

0.18

19. SI units of pressure is

(a)

pascal

(b)

atmosphere

(c)

metre

(d)

dyne/cm2

20. SI unit of emf is

(a)

joule

(b)

millivolt

(c)

volt

(d)

ampere

21. Part B

10 x 2 = 20
22. Calculate the molar mass of the following compounds. -Sulphurci  Acid [H2SO4]

23. Write a note on Thomson's plum pudding model of an atom.

24. What are the defects of Rutherford's model?

25. How many neutrons and protons are there in the Following nuclei?
$_{ 6 }^{ 13 }{ C }$,$_{ 2 }^{ 18 }{ O }$.$_{ 12}^{ 24}{ Mg }$,$_{26 }^{ 56}{ Fe }$,$_{ 88}^{ 38}{ Sr }$

26. Why Pauli exclusion principle is called exclusion principle?

27. Bring out the similarities and dissimilarities between a 1s and 2s orbital.

28. Calculate the wave length of an electron (mass = 9.1 x 10-31 kg) moving with 'a velocity of 10ms-1 (h = 6.6 x 10-34 kg m2 sec-1).

29. The kinetic energy of a subatomic particle is 5.58 x 10-25 J. Calculate the frequency of the particle wave. (Planck's constant h = 6.626 x 10-34 kg m2 s-1)

30. A microscope using suitable photons is employed to locate an electron in an atom within a distance of 0.1$\overset { o }{ A }$  What is the uncertainty involved in the measurement of its velocity.

31. Explain how matter has dual character?

32. Part C

10 x 3 = 30
33. Matter is defined as anything that has mass and occupies space. All matter is composed of atoms

34. Write a note on the differences between elements and compounds

35. Write down the formulae for calculating the equivalent mass of an acid, base and oxidizing agent.

36. 1.05g of a metal gives on oxidation 1.5g of its oxide. Calculate its equivalent mass.

37. A piece of cut apple becomes brown. Why? Can you prevent it by a simple method

38. Balance the following reaction:
H2C2O4+KMnO4 + H2SO4 $\rightarrow$ H2SO4 + MnSO4 + CO2 + H2O

39. Calculate the molar volume of 146 g of HCI gas and the number of molecules present in it

40. Calculate the molar mass of 20 L of gas weighing 23.2 g at STP.

41. Describe in brief Lothar Meyer's classification of elements.

42. Explain classification of elements based on Newland's law of Octaves.

43. Part D

6 x 5 = 30
44. Write note on combination reaction.

45. Arrange the elements silver, Zinc and copper in the order of their decreasing electron releasing tendency and justify your arrangement with an appropriate experiment.

46. Balance the following equations by oxidation number method.
KBr + MnO2 + H2SO4 ⟶ KHSO4 + MnSO4 + H2O + Br2

47. Calculate the empirical and molecular formula of a compound containing 32% carbon, 4% hydrogen and rest oxygen. Its vapour density is 75.

48. Light of wavelength 12818 $\overset { o }{ A }$ is emitted when the electron of a hydrogen atom drops from 5th to 3rd orbit. Find the wavelength of a photon emitted when the electron falls from 3rd to 2nd orbit.

49. Explain about the factors that influence the ionization enthalpy.