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Chemistry WAEC / WASSCE 1997 Atomic Structure, Orbitals & Nuclear Chemistry
An atom 17 protons, 17 electrons and 18 neutrons has a mass number of
A
17
B
18
C
34
D
35
E
52
medium Difficulty
Chemistry WAEC / WASSCE 1997 Acids, Bases, pH & Salts
If an element R belongs to the same group as sodium, an aqueous solution of ROH will
A
be neutral
B
be acidic
C
be coloured
D
have pH greater than 7
E
turn back litmus red
medium Difficulty
Chemistry WAEC / WASSCE 1997 Atomic Structure, Orbitals & Nuclear Chemistry
Element X, with electronic configuration 2, 8, 2 and element Y with electronic configuration 2, 8, 7 are like to combine by
A
metallic bonding
B
covalent bonding
C
electrovalent bonding
D
dative bonding
E
hydrogen bonding
medium Difficulty
Chemistry WAEC / WASSCE 1997 Stoichiometry, Mole Concept & Volumetric Analysis
The valence electrons of element 12Mg are in the
A
1s orbital
B
2s orbital
C
2px orbital
D
2py orbital
E
3s orbital
medium Difficulty
Chemistry WAEC / WASSCE 1997 Chemical Bonding & Intermolecular Forces
Which of the following statements is correct about sodium chloride in the solid state?
A
it exists as aggregates of ions
B
it conducts electricity
C
its melting point is below 100oC
D
it exists as discrete molecules
E
its ions are linked by metallic bonds
medium Difficulty
Chemistry WAEC / WASSCE 1997 Periodic Table & Periodicity
Which of the following Group 1 elements has the highest ionization energy?
A
55Cs
B
37Rb
C
19K
D
11Na
E
3Li
medium Difficulty
Chemistry WAEC / WASSCE 1997 Kinetic Theory of Matter & Gas Laws
What volume of oxygen at s.t.p would react with carbon to form 4.40g of CO2 according to the following equation? C(s) + O2(g) → CO2(g) [O = 16; C =12; 1 mole of a gas occupies 22.4dm3 at s.t.p]
A
0.224dm3
B
2.24dm3
C
4.40dm3
D
4.48dm3
E
22.4dm3
medium Difficulty
Chemistry WAEC / WASSCE 1997 Nature of Matter & Separation Techniques
A mixture of NaCI(s) and CaCO3(s) is best separated by
A
dissolution followed by filtration
B
sublimation followed by crystallization
C
dissolution followed by evaporation
D
dissolution followed by crystallization
E
sublimation followed by dissolution
medium Difficulty
Chemistry WAEC / WASSCE 1997 Stoichiometry, Mole Concept & Volumetric Analysis
What is the basicity of the acid in the followed reaction? NaCO + 2CHCOOH → 2CH COONa + H2O + CO2
A
1
B
2
C
3
D
4
E
8
medium Difficulty
Chemistry WAEC / WASSCE 1997 Stoichiometry, Mole Concept & Volumetric Analysis
All your burette readings (initial and final), as well as the size of your pipette, must be recorded but on no account of experimental procedure is required. All calculations must be done in your answer book. A is 0.50 mol dm\(^{-3}\) hydrochloric acid. B is 0.025 mol dm\(^{-3}\) of a trioxocarbonate (IV) salt. (a) Put A into the burette and titrate with 20.0cm\(^{-3}\) or 25.0 cm\(^{-3}\) portions of B using methyl orange or screened methyl Orange indicator. Record the volume of your pipette. Tabulate your burette readings and calculate the average of A used. (b) From your results, calculate the mole ratio of acid to trioxocarbonate (IV) in the reaction, expressing your answer as a whole number ratio of one. (c) Given that B contains 7.2g dm\(^{-3}\) of the hydrated trioxocarbonate (IV) salt, calculate the: (i) concentration of anhydrous salt in B in g dm\(^{-3}\) [Molar mass of anhydrous salt in B = 106g] (ii) percentage of water of crystallization in the hydrated salt.
A
1
B
2
C
3
D
4
E
8
medium Difficulty
Chemistry WAEC / WASSCE 1997 Atomic Structure, Orbitals & Nuclear Chemistry
(a) List two properties of alpha particles. (b) X is an element which exists as an isotopic mixture containing 90% of \(^{39}_{19} X\) and 10% of \(^{41}_{19}X\). (i) How many neutrons are present in the isotope \(^{41}_{19}X\)? (ii) Calculate the mean relative atomic mass of X.
medium Difficulty
Chemistry WAEC / WASSCE 1997 Nature of Matter & Separation Techniques
(a)(i) State the two main processes involved in the manufacture of oxygen from air (ii) Name the type of chemical bonding which exists between oxygen atoms in a molecule of oxygen (b) What term is used to describe the relationship between oxygen and ozone (O\(_3\))?
medium Difficulty
Chemistry WAEC / WASSCE 1997 Electrolysis & Electrochemical Cells
(a) List two industrial uses of concentrated tetraoxosulphate (VI) acid (b) The diagram below represents the set-up for the electrolysis of dilute tetraoxosulphate (VI) acid. Use it to answer Questions (i) to (iii). (i) Which letter on the diagram represents the battery? (ii) Write an equation for the reaction occurring at the cathode (iii) What product does V represent?
medium Difficulty
Chemistry WAEC / WASSCE 1997 Acids, Bases, pH & Salts
(a) State two properties of alkalis (b)(i) Why is tetraoxosulphate (VI) acid able to produce two types of salt? (ii) Write an equation for the reactior involved on heating sodium trioxosulphate (IV) with hydrochloric acid.
medium Difficulty
Chemistry WAEC / WASSCE 1997 Reaction Rates & Chemical Equilibrium
Consider the reaction represented by the following Q equation: N\(_2\)O\(_{4(g)}\) \(\rightleftharpoons\) 2NO\(_{2(g)}\) \(\Delta\)H = +57.2KJmol\(^{-1}\) (a) When is the reaction said to be at equilibrium? (b) Mention two conditions that can favour the forward reaction (c) Name the principle involved in (b) above.
medium Difficulty
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