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Chemistry Past Questions

Study and practice Chemistry past questions with answers and detailed explanations. Then test your knowledge using our interactive CBT practice platform and prepare confidently for your upcoming examinations.

4,306 questions JAMB 2505 WAEC 1623 NECO 168 CUSTOM 10
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Past Questions

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Question 1 of 20 4,306 total questions
Question 781
waec 2012
MgO does not readily dissolve in water because
Aof its high melting point
Bit is a covalent compound
Cit forms a hydroxide when dissolved in water
Dits lattice energy is higher than its hydration energy
View Explanation & Discuss
Question 782
waec 2012

The vapour pressure of a liquid depends on l. temperature. ll. rate of condensation. III. cohesive forces holding the particles together

Al only
Bl and ll only
Cl and lll only
Dll and lll only
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Question 783
waec 2012

The complex compound formed when aluminum dissolves in aqueous sodium hydroxide is

ANa3Al(OH)4.
BNaAl(OH)4
CNaAl(OH)3
DNa2Al(OH)3
View Explanation & Discuss
Question 784
waec 2012

The complex compound formed by the combination of two elements with a large electronegativity difference is likely to be

Apolar covalent
Bgiant molecular
Ccovalent
Dionic
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Question 785
waec 2012

The shape of a graphite crystal is

Atetrahedral
Bpyramidal
Chexagonal
Doctahedral
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Question 786
waec 2012

Which of the following halogens is liquid at room temperature?

AChlorine
BFluorine
Clodine
DBromine
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Question 787
waec 2012

Which of the following elements is a metalloid?

ACarbon
BOxygen
CSilicon
DSodium
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Question 788
waec 2012

Which of the following statements about a radioactive substance is/are correct? l. lt emits radiation continuously and spontaneously. ll. The emitted radiations are affected by temperature and pressure III. The radiation can penetrate opaque matter

All only
Bl and ll only
Cl and lll only
Dll and lll only
View Explanation & Discuss
Question 789
waec 2012

The d-block elements are paramagnetic because they

Acontain paired electrons which are repelled by magnetic field
Bcontain unpaired electrons in the partially filled 3d-orbital
Ccontain paired electrons which are repelled by magnetic field force
Dhave delocalized valence electrons
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Question 790
waec 2012

Two elements, X and Y are in the same group on the periodic table because they both have the same

Anumber of electronic shells
Bnumber of valence electrons
Catomic size
Datomic number
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Question 791
waec 2012

The atomic radii of metals are usually

Agreater than their ionic radii
Bequal to their ionic radii
Cless than their ionic radii
Dless than those of non-metals in the same period
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Question 792
waec 2012

Which of the following ions has an electron configuration different from the other?

A17CI-
B8O2-
C12Mg2+
D13AI3+
View Explanation & Discuss
Question 793
waec 2012

Which of the following electron configurations represents that of an atom in its ground state?

A1s 22s12p1
B1s22s22p63s13p1
C1s22s12p3
D1s22s22p63s0
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Question 794
waec 2012

The number of orbitals in a p-sub level of an atom is

A2
B3
C5
D6
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Question 795
jamb 2012
An example of oxidation - reduction enzyme is
Aamylase
Bprotease
Clipase
Ddehydrogenase
View Explanation & Discuss
Question 796
jamb 2012

Ethanol reacts with concentrated tetraoxosulphate (VI) acid at a temperature above 170\(^0\)C to form

Aethanone
Bethene
Cethyne
Dethanal
View Explanation & Discuss
Question 797
jamb 2012
2 - methyl propan -2- ol is an example of a
Aprimary alkanol
Bsecondary alkanol
Ctertiary alkanol
Dquartenary alkanol
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Question 798
jamb 2012

The saponification of an alkanoate to produce soap and alkanol involves

Adehydration
Besterification
Chydrolysis
Doxidation
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Question 799
jamb 2012
A compound contains 40.0% C, 6.7% H 53.3% O. If the molecular mass of the compound is 180, its molecular formula is [C =12, H =1,O]
ACH2O
BC3H6O3
CC6H6O3
DC6H12O6
View Explanation & Discuss
Question 800
jamb 2012

Carbohydrates are large molecules with the molecular formula C\(_x\)(H\(_2\)O)\(_y\). In which of the following pairs is x not equal to y?

Aglucose and starch
Bmaltose and starch
Csucrose and fructose
Dgalactose and starch
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