1997 - JAMB Chemistry Past Questions and Answers - page 5
41
(1 /(2) N2(g) + (1) / (2)O2(g) → NO(g) ∆H° 89 KJ mol-. If the entropy change for the reaction above at 25°C is 11.8 J mol-, calculate the change in free energy. ∆G°, for the reaction at 25°C?
A
88.71 KJ
B
85.48 KJ
C
-204.00 KJ
D
-3427.40 KJ
correct option: d
∆G = ∆H - T∆S; T = 2s° + 273 = 298 k
∆G = 89 - 298 x 11.8 = -3427.4
Users' Answers & Comments∆G = 89 - 298 x 11.8 = -3427.4
42
Use the graph above to answer this question. A sample, X, solid at room temperature, was melted, heated to a temperature of 358 K and allowed to cool as shown in OPQR. The section PQ indicates that X is
A
a mixture of salts
B
a hydrated salt
C
an ionic salt
D
a pure compound
correct option: d
Users' Answers & Comments43
Use the graph above to answer this question. A sample, X, solid at room temperature, was melted, heated to a temperature of 358 K and allowed to cool as shown in OPQR.The section OP suggests that X is in the
A
liquid sate
B
solid/liquid state
C
solid state
D
gaseous state
correct option: a
Users' Answers & Comments44
In the diagram above the gas Y could be
A
hydrogen chloride
B
oxygen
C
carbon (IV) oxide
D
chlorine
correct option: a
Users' Answers & Comments45
The IUPAC nomenclature of the organic compound with the above structural formula is
A
3-ethyl-2,5-dimethylhexane
B
4-ethyl-2,5-dimethylhexane
C
3-ethyl-2,5,5 - trimethylpentane
D
3-ethyl, 1,1,4-trimethylpentane
correct option: a
Users' Answers & Comments46
How many more isomers of the compound above can be obtained ?
A
5
B
4
C
3
D
2
correct option: b
Users' Answers & Comments47
Choose the correct answer from the options above. When Fehling is solution is added to two isomeric carbonyl compounds X and Y with the molecular formula C 5H 10O, compound X gives a red precipitate while Y does not react. It can be inferred that X is
A
A
B
B
C
C
D
D
correct option: b
Users' Answers & Comments48
The compound above contains
A
Sp 3 hybridized carbon atoms only
B
Sp 2 hybridized carbon atoms only
C
Sp 3 and Sp hybirdized carbon atoms
D
Sp 3 and Sp 2
correct option: d
Users' Answers & Comments49
The compound above is the product of the oxidation of
A
2-methlbutan-2-ol
B
2-methylbutan -1- ol
C
2, 3-dimethylprop 1-ol
D
Pentan -2- ol
correct option: b
Users' Answers & Comments