WAEC Chemistry questions

357 questions with answers and explanations. Tap an option to check yourself.

All topics Acids, bases and salts · 26 Air · 16 Atomic structure and bonding · 26 Chemical combination · 27 Chemical equilibrium · 16 Chemistry and industry · 17 Electrolysis · 19 Energy changes · 16 Environmental pollution · 15 Kinetic theory of matter and gas laws · 18 Metals and their compounds · 23 Non-metals and their compounds · 22 Organic compounds · 29 Oxidation and reduction · 19 Rates of chemical reaction · 16 Separation of mixtures and purification · 18 Solubility · 16 Water · 18

Question 61· Atomic structure and bonding· WAEC
What is the electron configuration of an atom of atomic number 13?
Explanation and discussion
Question 62· Atomic structure and bonding· WAEC
The atoms ³⁵Cl and ³⁷Cl differ in their number of
Explanation and discussion
Question 63· Atomic structure and bonding· WAEC
The electron configuration of chlorine (atomic number 17) is
Explanation and discussion
Question 64· Atomic structure and bonding· WAEC
Isotopes of an element have
Explanation and discussion
Question 65· Atomic structure and bonding· WAEC
The shape of a methane molecule is
Explanation and discussion
Question 66· Atomic structure and bonding· WAEC
The particles found in the nucleus of an atom are
Explanation and discussion
Question 67· Atomic structure and bonding· WAEC
An atom of an element has 11 protons and 12 neutrons. Its mass number is
Explanation and discussion
Question 68· Atomic structure and bonding· WAEC
The element with electron configuration 2, 8, 2 belongs to
Explanation and discussion
Question 69· Chemical combination· WAEC
Calculate the percentage by mass of nitrogen in ammonium trioxonitrate(V), NH₄NO₃. [N = 14, H = 1, O = 16]
Explanation and discussion
Question 70· Chemical combination· WAEC
What volume does 0.25 mol of carbon(IV) oxide occupy at s.t.p.? [molar volume = 22.4 dm³]
Explanation and discussion
Question 71· Chemical combination· WAEC
Pure water from any source always contains hydrogen and oxygen in the mass ratio 1 : 8. This illustrates the law of
Explanation and discussion
Question 72· Chemical combination· WAEC
How many moles are in 9 g of water? (H = 1, O = 16)
Explanation and discussion
Question 73· Chemical combination· WAEC
The law of conservation of mass states that in a chemical reaction
Explanation and discussion
Question 74· Chemical combination· WAEC
How many moles are in 36 g of water? (H = 1, O = 16)
Explanation and discussion
Question 75· Chemical combination· WAEC
The empirical formula of a compound whose molecular formula is C₂H₆ is
Explanation and discussion
Question 76· Chemical combination· WAEC
In 2Mg + O₂ → 2MgO, how many moles of magnesium oxide are formed from 4 mol of magnesium?
Explanation and discussion
Question 77· Chemical combination· WAEC
The valency of aluminium in Al₂O₃ is
Explanation and discussion
Question 78· Chemical combination· WAEC
Calculate the mass of 0.2 mol of NaCl. (Na = 23, Cl = 35.5)
Explanation and discussion
Question 79· Chemical combination· WAEC
In the equation 2H₂ + O₂ → 2H₂O, the mass of water formed from 4 g of hydrogen is
Explanation and discussion
Question 80· Chemical combination· WAEC
When the equation aAl + bO₂ → cAl₂O₃ is balanced, a, b and c are
Explanation and discussion

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WAEC Chemistry questions

What is the electron configuration of an atom of atomic number 13?

The atoms ³⁵Cl and ³⁷Cl differ in their number of

The electron configuration of chlorine (atomic number 17) is

Isotopes of an element have

The shape of a methane molecule is

The particles found in the nucleus of an atom are

An atom of an element has 11 protons and 12 neutrons. Its mass number is

The element with electron configuration 2, 8, 2 belongs to

Calculate the percentage by mass of nitrogen in ammonium trioxonitrate(V), NH₄NO₃. [N = 14, H = 1, O = 16]

What volume does 0.25 mol of carbon(IV) oxide occupy at s.t.p.? [molar volume = 22.4 dm³]

Pure water from any source always contains hydrogen and oxygen in the mass ratio 1 : 8. This illustrates the law of

How many moles are in 9 g of water? (H = 1, O = 16)

The law of conservation of mass states that in a chemical reaction

How many moles are in 36 g of water? (H = 1, O = 16)

The empirical formula of a compound whose molecular formula is C₂H₆ is

In 2Mg + O₂ → 2MgO, how many moles of magnesium oxide are formed from 4 mol of magnesium?

The valency of aluminium in Al₂O₃ is

Calculate the mass of 0.2 mol of NaCl. (Na = 23, Cl = 35.5)

In the equation 2H₂ + O₂ → 2H₂O, the mass of water formed from 4 g of hydrogen is

When the equation aAl + bO₂ → cAl₂O₃ is balanced, a, b and c are