Multiple Choice QuestionsThe heat of combustion of carbon to CO2 is -395.5 kJ/mol. The heat released upon the formation of 35.2 g CO2 from carbon and oxygen gas isÂ
-315 kJ
+315 kJ
-630 kJ
-630 kJ
The formation of the oxide ion O2- (g), from oxygen atom requires first an exothermic and then an endothermic step as shown below,
Thus, the process of formation of O2- in the gas phase is unfavourable even though O2- is isoelectronic with neon. It is due to the fact that
electron repulsion outweighs the stability gained by achieving a noble gas configuration
O- ion has comparatively smaller size that oxygen atom
oxygen is more electronegative
oxygen is more electronegative
Consider the following processes Δ H (kJ/mol)
1/2 A →                +150
3B   → 2 C + D           -125
E + A  → 2D             +350
For  B + D   → E + 2C, ΔH will beÂ
525 kJ/mol
-175 kJ/mol
-325 kJ /mol
-325 kJ /mol
Standard entropies X2, Y2 and XY2 are 60, 40 and 50 J K-1 mol-1 respectively for the reaction
equilibrium, the temperature should be
750 K
1000 KÂ
1250 K
1250 K
Three moles of an ideal gas expanded spontaneously into the vacuum. The work done will be
infinte
3 J
9 J
9 J
Match List I (equation) with List II (types of the process) and select the correct option.
|
List I (Equations)
|
List II (Types of process)
|
||
|
A |
KP > Q |
1 |
Non-spontaneous |
|
B |
ΔGo < RT In Q |
2 |
Equilibrium |
|
C |
KP = Q |
3 |
Spontaneous and endothermic |
|
D |
T> ΔH/ ΔS |
4 |
Spontaneous |
|
A
|
B
|
C
|
D
|
|
1
|
2
|
3
|
4
|
| A | B | C | D |
| 3 | 4 | 2 | 1 |
| A | B | C | D |
| 4 | 1 | 2 | 3 |
| A | B | C | D |
| 4 | 1 | 2 | 3 |
The values of ΔH and ΔS for the reaction, C(graphite) + CO2(g) → 2 CO (g) are 170 kJ and 170 JK-1 respectively. This reaction will be spontaneous at
710 KÂ
910 K
1110 K
1110 K
Which of the following are not state functions?
I) q + W
II) q
III) W
IV) H-TS
(I) and (IV)
(II) (III) and (IV)
(I), (II) and (III)
(I), (II) and (III)
D.
(I), (II) and (III)
A state function is the property of the system whose value depends only on the initial and final state of the system and is independent of the path.
Therefore,Â
Internal energy (ΔE) = q +W
It is a state function because it is independent of the path. It is an extensive property.
∴ Gibbs energy (G) = H -TS
It is also a state function because it is independent of the path. It is also extensive property.Â
Heat (q) and work (W) are not state functions being path dependent.
For the gas phase, reaction,
PCl5 (g) ⇌ PCl3 (g) Cl2 (g)
Which of the following conditions are correct?
Δ H = 0 and ΔS > 0
ΔH >0 and ΔS > 0
Δ H < 0 and ΔS < 0
Δ H < 0 and ΔS < 0
Consider the following reactions:
Enthalpy of formation of H2O (l) is:
- x2 kJ mol-1
+ x3 kJ mol-1
- x4Â kJ mol-1
- x4Â kJ mol-1
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