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10g of a solid is in equilibrium with its own vapour.
When 1 g of a small amount of solid is added, the vapour pressure?
Aremains the same
Bdrops
Cincreases by 1%
Dincreases by 99%
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Question 32
jamb1993
The standard enthalpies of formation of CO2(g), H2O(g) and CO(g) in kJ mol- are -394, -242 and -110 respectively. What is the standard enthalpy change for the reaction CO(g) + H2(g)O → CO2(g) + H2(g)?
A-42 KJ mol-
B+42 KJ mol-
C-262 KJ mol-
D+262 KJ mol-
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Question 33
jamb1993
A reaction takes places spontaneously if?
A∆G = O
B∆S < O and ∆H > O
C∆H < T ∆S
D∆G > O
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Question 34
jamb1993
The oxidation states of chlorine in HOCL, HCLO3 and HCLO4 are respectively?
A-1, +5, and +7
B-1, -5 and 7
C+1, +3 and +4
D+1, +5 and +7
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Question 35
jamb1993
Which of the reactions occurs at the anode during the electrolysis of a very dilute aqueous solution of sodium chloride?
AOH- - e → OH
BCIsup>- - e → CI
COHsup>- + CIsup>-HCI + O2
DNa+ - esup>- Hg (Na)/(Hg) amalgam
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Question 36
jamb1993
During the electrolysis of a salt of a metal M, a current of 0.5 A flows from for 32 minutes 10 seconds and deposits 0.325 g of M, What is the charge of the metal ion?
(M = 65, If = 96,500 C per mole of electron)
A1
B2
C3
D4
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Question 37
jamb1993
4.0 g of sodium hydroxide in 250 cm3 of solution contains?
A0.40 moles per dm3
B0.10 moles per dm3
C0.04 moles per dm3
D0.02 moles per dm3
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Question 38
jamb1993
NH\(_3\) + H\(_3\)O\(^+\) → NH\(_4\)\(^+\) + H\(_2\)O. It may be deduced from the reaction above that?
Aa redox reaction has occurred
BH3O+ acts as an oxidizing agent
CH3O+ acts as an acid
Dwater acts as an acid
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Question 39
jamb1993
A student prepares 0.5 M solution each of hydrochloric and ethanoic acids and then measured pH. The result would show that the?
ApH values are equal
BHCI solution has a higher pH
Csum of the values is 14
Dethanoic acid solution has a higher pH
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Question 40
jamb1993
The phenomenon whereby sodium trioxocarbonate (IV) decahydrate loses some of its water of crystallization on exposure to the atmosphere is known as?
Adeliquescene
Bhygroscopy
Ceffervescence
Defflorescence
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Question 41
jamb1993
Water can be identified by the use of?
Aanhydrous copper (II) tetraoxosulphate (VI)
Banhydrous sodium trioxocarbonate (IV)
Cpotassium heptaoxochromate (VII)
Dcopper (II) trioxocaronate (IV)
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Question 42
jamb1993
The air around a petroleum refinery is most likely to contain?
ACO2, SO3 and N2O
BCO2, CO and N2O
CSO2, CO and NO2
DPH3 H2O and CO2
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Question 43
jamb1993
Argon is used in gas-filled electric lamp because it helps to?
Aprevent the reduction of the lamp fillaments
Bprevent oxidation of the lamp fillaments
Cmake the lamp fillament glow brightly
Dkeep the atmosphere in the lamp inert
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Question 44
jamb1993
Water has a rather high boiling point despite its low molecular mass because of the presence of?
Ahydrogen bonding
Bcovalent bonding
Cionic bonding
Dmetallic bonding
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Question 45
jamb1993
Which group of elements forms hydrides that are pyramidal in structure?
AIII
BIV
CV
DVI
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Question 46
jamb1993
As the difference in electronegativity between bonded atoms increases, polarity of the bond?
Adecreases
Bincreases
Cremains unchanged
Dreduces to zero
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Question 47
jamb1993
Two atoms represented as U and U are?
Aisomers
Ballotropes
Cisotopes
Danomers
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Question 48
jamb1993
An element, E, has the electronic configuration 1s22s22p63s2p3. The reaction of E with a halogen X can give?
AEX3 and EX5
BEX3 only
CEX5 only
DEX2 and EX3
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Question 49
jamb1993
For iodine crystals to sublime on heating, the molecules must acquire energy that is?
Aless than the forces odf attraction in the solid
Bequal to the forces of attraction in th solid
Cnecessary to melt the solid
Dgreater than the forces of attraction in both the solid and the liquid phases
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Question 50
jamb1993
How many moles of oxygen molecules would be produced from the decomposition of 2.50 moles of potassium trioxochlorate (V)?
