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Chemistry WAEC / WASSCE 2018 Stoichiometry & Mole Concept
The empirical formula of a compound containing 0.067mol Cu and 0.066mol O is [Cu = 63.5, O = 16]
A
\(Cu_{2}O\)
B
\(CuO\)
C
\(CuO_{2}\)
D
\(CuO_{4}\)
medium Difficulty
Chemistry WAEC / WASSCE 2018 Electrochemistry and Redox
The change in the oxidation state of iron in the reaction represented by the equation: \(2FeCl_{3} + H_{2}S \to 2FeCl_{2} + 2HCl + S\) is
A
+2 to +3
B
0 to +2
C
+3 to +2
D
+3 to 0
medium Difficulty
Chemistry WAEC / WASSCE 2018 Matter & Separation Techniques
Which of the following methods can be used to seperate blood cells from plasma?
A
Centrifugation
B
Filtration
C
Chromatography
D
Distillation
medium Difficulty
Chemistry WAEC / WASSCE 2018 Atomic Structure and Periodic Table
Which of the following statements is true about ionic radius? Ionic radius
A
increases as nuclear charge increases
B
decreases as nuclear charge increases
C
decreases as nuclear charge decreases
D
remains constant as nuclear charge increases
medium Difficulty
Chemistry WAEC / WASSCE 2018 Stoichiometry & Mole Concept
Analysis of a hydrocarbon shows that it contains 0.93g of Carbon per gram of the compound. The mole ratio of carbon to hydrogen in the compound is [H = 1.0, C=12.0]
A
1:1
B
1:2
C
2:1
D
2:3
medium Difficulty
Chemistry WAEC / WASSCE 2018 Stoichiometry & Mole Concept
The law of definite proportions states that
A
pure samples of the same compound contain the same elements combined in the same proportion by mass
B
pure samples of substances are in the same proportion by mass
C
chemical compounds are pure because they contain the same elements
D
matter can neither be created nor destroyed.
medium Difficulty
Chemistry WAEC / WASSCE 2018 Stoichiometry & Mole Concept
What is the relative molecular mass of a compound which has empirical formula \(CH_{2}O\)? [C= 12, H= 1, O= 16]
A
42
B
45
C
126
D
180
medium Difficulty
Chemistry WAEC / WASSCE 2018 Atomic Structure and Periodic Table
Atoms are electrically neutral because they
A
do not conduct electricity
B
contain equal number of protons and electrons
C
are composed of neutrons and electrons
D
cannot be attracted by electromagnetic field.
medium Difficulty
Chemistry WAEC / WASSCE 2018 Acids, Bases, and Salts
Common Salt (NaCl) is used to preserve foods. Which of the following properties can be used to determine its purity before use?
A
Solubility in water
B
Melting point
C
Relative density
D
Crystalline nature
medium Difficulty
Chemistry WAEC / WASSCE 2018 Atomic Structure and Periodic Table
Which of the following electron configurations represents the transition element Chromium \(_{24}Cr\)?
A
\(1s^{2} 2s^{2} 2p^{6} 3s^{2} 3p^{6} 4s^{2} 3d^{4}\)
B
\(1s^{2}2s^{2}2p^{6}3s^{2}3p^{6}3d^{6}\)
C
\(1s^{2}2s^{2}2p^{6}3s^{2}3d^{4} 4s^{1}\)
D
\(1s^{2}2s^{2}2p^{6}3s^{2}3p^{6}4s^{1}3d^{5}\)
medium Difficulty
Chemistry WAEC / WASSCE 2018 Atomic Structure and Periodic Table
The atomic number of an isotope of hydrogen is equal to its mass number because it
A
has a totally filled valence shell
B
has a high charge to mass ratio
C
does not contain neutrons
D
exhibits isotopy
medium Difficulty
Chemistry WAEC / WASSCE 2018 Atomic Structure and Periodic Table
What is the total number of shared pair of electrons in the compound above?
Attached Figure / Diagram
Question diagram
A
5
B
8
C
10
D
12
medium Difficulty
Chemistry WAEC / WASSCE 2018 Atomic Structure and Periodic Table
The bonding pair of electrons in a Hydrogen Chloride molecule is pulled towards the chlorine atom because
A
chlorine has a larger atomic size
B
chlorine has a larger atomic mass
C
chlorine is more electronegative
D
there is no bonding orbitals within the hydrogen atom
medium Difficulty
Chemistry WAEC / WASSCE 2018 Atomic Structure and Periodic Table
The solubility of \(CO_{2}\) in water can be accounted for by
A
Van der Waal's forces
B
Ionic attraction
C
dipole attraction
D
covalent bonding
medium Difficulty
Chemistry WAEC / WASSCE 2018 Atomic Structure and Periodic Table
Which of the following properties would not influence electrovalent bond formation?
A
Electronegativity
B
Electron Affinity
C
Ionization potential
D
Catalytic ability
medium Difficulty
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