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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.

91 questions JAMB 2505 WAEC 1623 NECO 168 CUSTOM 10
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Past Questions

91 questions
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Question 1 of 20 91 total questions
Question 11
waec 1999
An exothermic reaction is one which involves
Aattainment of dynamic equilibrium
Bloss of heat to the surrounding
Cevolution of gas as it proceeds
Dpositive change in value of enthalpy
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Question 12
waec 1999

30cm3 pf hydrogen at s.t.p combine with 20cm3 of oxygen to form steam according to the following equation 2H2(g) + O2(g) → 2H2O(g).

Calculate the total volume of the gaseous mixture at the end of the reaction

A50cm3
B35cm3
C30cm3
D25cm3
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Question 13
waec 1999

Helium is preferred to hydrogen in filling balloons because hydrogen

Ais inflammable
Bis diatomic
Cexhibits isotopy
Dis a component of water
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Question 14
waec 1999
What volume of hydrogen is produced at s.t.p. When 2.60 g of zinc reacts with excess HCI according to the following equation? Zn(s) + 2HCI(aq) → ZnCI 2(aq) + H2(g) [Zn = 65; 1 mole of a gas occupies 22.4dm3 at s.t.p]
A0.040dm 3
B0.896dm 3
C5.82dm 3
D8.62dm 3
View Explanation & Discuss
Question 15
waec 1999
Gas molecules are said to be perfectly elastic because
Athey collide without loss of energy
Bthey move about in straight lines
Cthe distances between them are negligible
Dthe volume occupied by them is negligible
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Question 16
waec 1999
Equal volumes of CO2 cnd CO at s.t.p have the same
Amass
Bdensity
Crate of diffusion
Dnumber of molecules
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Question 17
waec 1999
Which of the following movements can be described as random motion?
Awheelbarrow being pushed
Bcar travelling on a straight line
CGas molecules colliding in a flask
DPlanets going round the sun
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Question 18
waec 1999
Exhaust fumes discharged from a smoky vehicle gradually become invisible as a result of
Adiffusion
Bcombustion
Cabsorption
Demission
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Question 19
waec 1999
One mole of a compound M(HCO3)2 has a mass of 162g. Calculate the relative atomic mass of M. [H = 1, C =12, O = 16]
A122
B101
C53
D40
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Question 20
waec 1999
If an element with high electron affinity combines with another element with low ionization energy the bond formed will be mainly
Acovalent
Bionic
Cdative
Dmetallic
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Question 21
waec 1999
Which of the following compounds has the highest ionic character?
APCI5
BSiCI4
CAICI3
DKCI
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Question 22
waec 1999

The crystal layers in graphite are held together by

Aelectrostatic forces
Bvan der Waals' forces
Chydrogen bonds
Dcovalent bonds
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Question 23
waec 1999
Which of the following halogens is the most reactive?
AF2
BBr2
Cl2
DCl
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Question 24
waec 1999

Which of the following reactions is not feasible?

ACl2 + 2Kl → 2KCI + I2
BCl2 + 2NaF → 2NaCI + F2
CZn + CuCI2 → ZnCl2 + Cu
DZn + 2AgNO3 → Zn(NO3)2 + 2Ag
View Explanation & Discuss
Question 25
waec 1999
In the Periodic Table, the elements that loss electrons most readily belong to
AGroup 1 A
BGroup 11 A
CGroup 111 A
DGroup V11 A
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Question 26
waec 1999
Which of the following properties increases down a group in the Periodic Table?
AAtomic radius
BElectronegativity
CElecton affinity
DIonization energy
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Question 27
waec 1999
Calcium atom ionizes by
Againing two electrons
Blosing two electrons
Csharing two electrons
Dgaining two protons
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Question 28
waec 1999
Two radioactive elements Q and S have half-life periods of 10 hours and 20 hours respectively. Therefore
AS decays faster than Q
BQ is twice as stable as S
CQ emits fewer particles than S
DS is more stable than Q
View Explanation & Discuss
Question 29
waec 1999
Which of the orbitals 4s, 4p, 4d and 4f has the lowest energy?
A4f
B4p
C4d
D4s
View Explanation & Discuss
Question 30
waec 1999
Pauli Exclusion Principle is related to
Aquantum numbers of electrons
Breversiblility of equlibrium reactions
Celectronegativity values of elements
Dcollision theory of reaction rates
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