If for H2(g) + ½ O2(g) → H2O(g)ΔH1 is the enthalpy of reaction and for H2(g) + ½ O2(g) → H2O (l)ΔH2 is enthalpy of reaction, then.. [ Pb. CET 1990]
38%
a) ΔH1 > ΔH2
25%
b) ΔH1=ΔH2
38%
c) ΔH1 < ΔH2
0%
d) ΔH1 + ΔH2=0
Q.6.
Heat of neutralisation of strong acid and strong base is nearly equal to ...[ AIIMS 1988]
20%
a) 10 kJ/mole
30%
b) 10 cal/mole
40%
c) -57 kJ/mole
10%
d) -57 Cal/mole
Q.7.
If ΔH is the change in enthalpy and ΔE, the change in internal energy accompanying a gaseous reaction, then ..[ CBSE PMT 1990]
40%
a) ΔH is always greater than ΔE
40%
b) ΔH < ΔE only if the number of moles of products is greater than the number of moles of the reactants
10%
c) ΔH is always less than ΔE
10%
d) ΔH < ΔE only if the number of moles of products is less than the number of moles of the reactants
Q.8.
In which of the following, the entropy decreases? [ CPMT 1988]
50%
a) Crystallisation of sucrose from solution
25%
b) Rusting of iron
0%
c) Melting of ice
25%
d) Vaporization of camphor
Q.9.
If H+ + OH- → H2O + 13.7 kcalthen heat of complete neutralisation of one gram mole of H2SO4 with a base will be [ MP 1990]
50%
a) 13.7 kcal
38%
b) 27.4 kcal
0%
c) 6.85 kcal
12%
d) 3.425 kcal
Q.10.
A mixture of 2moles of carbon monoxide and one mole oxygen in a closed vessel in ignited to get carbon dioxide. If ΔH is the enthalpy change and ΔE is the change in internal energy, then ..[ MP PMT 1998]
22%
a) ΔH > Δ E
56%
b) Δ H < Δ E
11%
c) Δ H=Δ H
11%
d) not definite
Q.11.
The molar neutralisation heat for KOH and HNO3 as compaired to molar neutralisation heat of NaOH and HCl is ..[ MP PMT 1989]
12%
a) Less
25%
b) more
62%
c) equal
0%
d) depends on pressure
Q.12.
The enthalpy at 298K of the reactionH2O2 → H2O(l) + ½ O2(g)is -23.5 kcal/mol and enthalpy of formation of H2O2(l) is -44.8 kcal/mol. The enthalpy of formation of H2O(l) is ... [ Pb. CET 1988]
60%
a) - 68.3 kcal/mol
40%
b) 68.3 kcal/mol
0%
c) -91.8 kcal/mol
0%
d) 91.8 kcal/mol
Q.13.
Which of the following is an endothermic reaction? [ IIT 1989]
25%
a) 2H2 + O2 → 2H2O
38%
b) N2 + O2 → 2NO
38%
c) 2NaOH + H2SO4 → Na2SO4 + 2H2O
0%
d) C2H5OH + 3O2 → 2CO2 + 3H2O
Q.14.
If CH3COOH + OH- → CH3COO- + H2O + q1H+ + OH- → H2O + q2then the enthalpy change for the reactionCH3COOH → CH3COO- + H+ is equal to ..[Pb.CET 1988]
27%
a) q1 + q2
18%
b) q1 - q2
55%
c) q2 - q1
0%
d) -q1 + q2
Q.15.
When 1M H2SO4 is completely neutralised by sodium hydroxide, the heat liberated is 114.64kJ. What is the enthalpy of neutralisation? [ Tamilnadu CET 2000]
0%
a) + 114.64 kJ
0%
b) - 114.64 kJ
80%
c) -57.32 kJ
20%
d) +57.32 kJ
Q.16.
H2 + 0.5 O2 → H2O; ΔH°=-68 kcalK + H2O + aq → KOH(aq) + 0.5H2; ΔH°=-48 kcalKOH + aq → KOH(aq) ; ΔH°=-14 kcalFrom the above data, the standard heat of formation of KOH in kcal is ... [ CPMT 1988]
17%
a) - 68 + 48 - 14
67%
b) - 68 - 48 + 14
17%
c) 68 - 48 + 14
0%
d) 68 + 48 + 14
Q.17.
Which of the following statements/relationship is not correct? [ Pb. CET 1989]
20%
a) In an exothermic reaction, the enthalpy of products is less than that of reactants
40%
b) ΔHfusion=ΔHsublimation -ΔHvaporisation
40%
c) A reaction for which ΔH° < 0 and ΔS° > 0 is possible at all temperatures.
0%
d) ΔH is less than ΔE for the reactionC(s) + ½O2(g) → CO(g)
Q.18.
Which of the following reaction can be used to define the heat of formation of CO2(g)? [ MP PMT 1989]
If ΔHf(X), ΔHf(Y), ΔHf(R) and ΔHf(S) denote the enthalpies of formation of X, Y,R and S respectively the enthalpy of the reactionX + Y → R + S is given .... [ Pb.CET 1898]
17%
a) ΔHf(X) + ΔHf(Y)
0%
b) ΔHf(R) + ΔHf(S)
50%
c) ΔHf(X) + ΔHf(Y) - ΔHf(R) - ΔHf(S)
33%
d) ΔHf(S) + ΔHf(R) - ΔHf(X) - ΔHf(Y)
Q.21.
One mole of a non-ideal gas undergoes a change of state (2.0atm, 3.0L, 95K) → (4.0 atm, 5.0L, 245K) with a chnage in internal energy, ΔU=30.0 L atm, The change in enthalpy ( ΔH ) of the process in L atm is ... [ IIT 2002 p
20%
a) 40.0
20%
b) 42.3
60%
c) 44.0
0%
d) not defined, because pressure is not constant
Q.22.
(diamond) → C(graphite) ; ΔH=-1.5 kJIt follows that
20%
a) diamond is exothermic
0%
b) graphite is endothermic
20%
c) graphite is stable than diamond
60%
d) diamond is stable than graphite
Q.23.
For the transition C(diamond) → C(graphite) ; ΔH = -1.5 kJ It follows that ... [ BHU 1981 ]
0%
a) diamond is exothermic
40%
b) graphite is endothermic
20%
c) graphite is stabler than diamond
40%
d) diamond is stabler than graphite.
Q.24.
Thermodynamic equilibrium involves .. [ Pb CET 1991]
20%
a) Chemical equilibrium
60%
b) Thermal equilibrium
0%
c) Mechanical equilibrium
20%
d) All the above
Q.25.
An isolated system is that system in which ...[ MP PMT 1993]
40%
a) there is no exchange of energy with the surroundings
0%
b) there is exchange of mass and energy with the surroundings
60%
c) there is no exchange of mass and energy with surroundings