sample paper
Chemistry (043) – XI
Session : 2023-24
General instructions:
1. There are 9 questions in this question paper. All questions are compulsory.
2. Q.No. 1 to 3 are very short answer questions carrying 1 mark each.
3. Q.No. 4 to 6 are short answer questions carrying 2 marks each.
4. Q.No. 7 & 8 are short answer questions carrying 3 marks each.
5. Q.No. 9 carry 5 marks
Q1 All bof the following have a standard heat of formation value of zero at
25°C and 1.0 atm except:
(a) N2(g)
(b) Fe(s)
(c) Ne (g)
(d) H(g)
Q2 A system suffers an increase in internal energy of 80 J and at the same time
has 50 J of work done on it. What is the heat change of the system?
(a) +130 J
(b) +30 J
(c) –130 J
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(d) –30 J
Q3 Choose the correct option out of the choices given below for following
question.
•
A and R both are correct, and R is correct explanation of A.
•
A and R both are correct, but R is not the correct explanation of A.
•
A is true but R is false.
•
A and R both are false.
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Assertion (A): Enthalpy of graphite is lower than that of diamond.
Reason (R): Entropy of graphite is greater than that of diamond
Q4 Derive the relationship Cp – Cv = R.
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Q5
2
•
Is the bond dissociation enthalpy of all the four C – H bonds in CH4
same? Give reason in support of your.
•
Given, N2(g) + 3H2(g) → 2NH3(g); ∆rHo = – 92.4 kJ/mol;
What is the standard enthalpy of formation of NH3 gas?
Q6 Predict the sign of ∆S for the following changes:
•
Freezing of water.
•
2NaHCO3(s) → Na2CO3(s) + CO2(g) + H2O(g)
•
H2(g) at 298 k and 1 bar → H2(g) at 298 k and 10 bar
•
H2(g) + I2(g) → 2HI(g)
Q7 Enthalpies of formation of CO(g), CO2(g), N2O(g) and N2O4(g) are –110, –
2
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393, 81 and 9.7 kJ mol-1 respectively. Find the value of ∆rH for the reaction;
N2O4(g) + 3CO (g) → N2O (g) + 3CO2 (g)
Q8 Calculate the lattice energy of CaCl2 from the given data
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Ca (s) + Cl2(g) → CaCl2(s) ∆ f H0 = − 795 kJ mol−1
ΔaH° of Ca(s) = +121 kJ mol−1
ΔIEH° of Ca(g) = +2422 kJ mol−1
ΔaH° of Cl2 (g) = +242.8 kJ mol−1
ΔegH° of Cl(g) = −355 kJ mol−1
Q9
•
Define the Hess's law of constant heat summation.
•
The entropy of steam is more than that of water at its boiling point
.explain
(C) A pump lifts water into the water tank at the top of a building. Is this
process
spontaneous?
(D) What is the free expansion? Determine work done in case of free
expansion of
an ideal gas.
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