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KV ITBP BHANU
Sample Paper for Cumulative Examination
Class- XI
Subject – Chemistry
Time Allowed : 3 Hrs.
M.M.70
General Instructions:
All questions are Compulsory.
1) Question nos. 1 to 8 are very short answer questions and carry 1 mark each.
2) Question nos. 9 to 18 are short answer questions and carry 2 marks each.
3) Question nos. 19 to 27 are also short answer questions and carry 3 marks each.
4) Question nos. 28 to 30 are long answer questions and carry 5 marks each.
5) Use Log tables if necessary, use of calculators is not allowed.
Q1. Give that relationship which relates wavelength and momentum of a moving electron.
Q2. Express the 32.968 number to three significant figure.
Q3. Write the equilibrium constant expression for the following reaction
AgBr (s)
Ag + (aq) + Br (aq)
Q4. State zeroth law of thermodynamics.
Q5. Why do elements in the same group have similar physical and chemical properties?
Q6. Draw the Lewis structure for the following molecules
SiCl4 , BeF2
Q7. What is the oxidation number of oxygen in H2O2?
Q8. Give mathematical expression of Charle’s Law.
Q9. Write electronic configuration of dioxygen molecule (O2).Prove that it is paramagnetic.
Q10. Find the pH of the following:(a) 2 x 10-3 M HCL(aq)
(b) 1 x 10-3 M KOH(aq)
Q11. A solution is prepared by adding 2g of a substance A to 18g of water. Calculate the
mass percent of the solute.
Q12. Calculate the wavelength of an electron moving with a velocity of 2.05 x 107 ms-1.
Q13. What is the basic difference in approach between Mendeleev’s Periodic Law and
Modern Periodic Law?
Q14. Enthalpy of combustion of carbon to CO2 is -393.5 KJ vol -1. Calculate the heat
released upon formation of 35.2g of CO2 from carbon and dioxygen gas.
Q15. Balance the following redox reaction by ion – electron method:MnO4 (aq) +Br – (aq) → MnO2(s) + BrO3 (aq) ( in basic medium)
Q16. Give two limitations of Bohr’s Atomic model?
OR
Give two limitations of Rutherford’s model ?
Q17. (a) Give any method of preparation of hydrogen.
(b) What is oxidation number of hydrogen in NaH.
Q18 What is electronegativity? How does it varies in group. Give reason.
Q19 (a) State Heinsberg’s uncertainty Principle.
(b) The uncertainity in the position and velocity of a particle are 10-2 m and 5.27x10-24
m/s respectively Calculate mass of the particle
L = 6.626 x 10-34 kg
Q20 Write the molecular orbital configuration of the following species
(a)
(b)
O2
-
O2 +
(i)
Calculate their bond orders.
(ii)
Perdict their magnetic behaviour.
OR
Write the resonating structures for NO-3, CO 3 2 -, SO 2
Q21 (a) Identify the substance oxidized , reduced , oxidizing agent and reducing agent for the
following :Pb (s) + PbO2(s) + 2H2SO4 (aq)
PbSO4 (s) + 2H2O(l)
(c) Write formulas for the following Compounds
(i) Mercury( II ) Chloride
(ii) Chromium (III) Oxide
Q22 Calculate the enthalpy of formation of acetic acid if its enthalpy of combustion is
-867 kg/mol. The enthalpy of formation of CO2 (g) and H2O(l) are -393.5 KJ/mol
and 285.9 KJ / mol respectively.
Q23 (a) Name the isotope of Hydrogen which is radioactive.
(b) Give formula and molecular mass of heavy water.
(c) Name two ions which cause hardness in water.
Q24 (a) Explain why BeH2 molecule has a zero dipole moment although the Be-H bonds
are polar.
(b) Use molecular orbital theory to explain why Be2 molecule does not exist.
(c) Out of LiF and LiCl which has more ionic character and why?
Q25 A compound contains 4.07% hydrogen , 24.27% carbon and 71.65% chlorine. Its
molar mass is 98.96g . What are its empirical and molecular formulas?
Q26 A neon – dioxygen mixture contains 70.6g dioxygen and 167.5g neon . If pressure of
the mixture of gases in the cylinder is 25 bar . What is the partial pressure of
dioxygen and neon in the mixture?
Q27 Explain the terms:(a) Solubility product
(b) Common ion effect
(c) Buffer Solutions
Q28 The following represents a gaseous system at equilibrium
2SO2 (g) + O2
2SO3 (g) +Heat
Indicate the direction in which the equilibrium will shift when the following changes
are made.
(i)
Temperature of the system is decreased.
(ii)
Total Pressure is added.
(iii)
A Catalyst is added
(iv)
Volume of Container is increased.
(v)
1 mole of He (g) is added at constant pressure.
OR
State Le Chatelier ‘s principle. Under what condition is it applicable ?
Discuss its application in the manufacture of ammonia by Habers Process.
Q29 What happens to work , when?
(i)
Gas expands irreversibly against an external pressure
(ii)
Gas is compressed.
(iii)
Gas expands into vacuum.
(iv)
An ideal gas expands reversibly and isothermally.
(v)
Gas expands adiabatically.
OR
Under what conditions , the heat evolved or absorbed in a reaction is equal to its free
energy change.
(i)
The standard free energy of a reaction is found to be zero, what is its equilibrium
constant.
(ii)
The dissolution of ammonium chloride in water is endothermic still it dissolves in
water .
(iii)
A real crystal has more entrophy than an ideal crystal.
(iv)
If
o
rH is negative and and
rS
o
is also negative whether the reaction will be
spontaneous or non- spontaneous at high temperature.
Q30 (a) Give the shape of molecules ammonia, water , PCl5 , CH4, BeCl2 , BCl3
(b) Describe the shape of ethene on the basis of hybridization.
OR
(a) Which of the following molecules are polar and which are non- polar and why?
BF3, NH3 , H2O
(b) Which of the following does not exist and why? (Explain on the basis of molecular
orbital theory)
He2 and H2