Chemistry

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WAEC NECO JAMB WASSCE JUPEB GCE

1.A normal body temperature is 37 o
C, Kw = 2.4 x 10-14. Calculate [H3O+
] and [OH]
for
the body fluid at this temperature.
A. [H3O+] = [OH]
= 2.5 x 10-7

B. [H3O+] = [OH]
= 1.5 x 10-8

C. [H3O+] = [OH]
= 1.5 x 10-6

D. [H3O+] = [OH]
= 1.5 x 10-7

2. Atoms of elements in a group on the Periodic Table have similar chemical properties.
This similarity is most closely related to the atoms’.
A. number of principal energy levels
B. number of valence electrons
C. atomic numbers
D. atomic masses

3. How many atoms of Cu are present in 35.4 g of Cu? [Cu = 63.5 gmol-1]
A. 1.08 x 1024 atoms of Cu
B. 3.27 x 1023 atoms of Cu
C. 6.02 x 1023 atoms of Cu
D. 1.20 x 1022 atoms of Cu

4. How would you prepare 250 cm3 of 0.25 M aqueous solution of NaCl?
[Na= 23 g mol-1
; Cl = 35.5 g mol-1]
A. Add 3.66 g NaCl to 250 cm3 of distilled water
B. Weigh 3.66 g NaCl into 250 ml flask and add distilled water up to the mark
C. Add 14.60 g NaCl to 250 cm3 of distilled water
D. Weigh 14.60 g NaCl into 250 ml flask and add distilled water up to the mark

5. What is the shape of PCl3?
A. Trigonal planar
B. Trigonal pyramidal
C. Tetrahedral
D. V-shaped (bent)

6. Uranium -233 (233U92) decays by α – emission. What is the decay product?
A. 229Th90
B. 231Th90
C. 231Ac91
D. 233Ac91

7. Arrange the following ions in order of decreasing charge density
Ca2+, Mg2+, Al3+ and Ba2+
A. Al3+> Mg2+>Ca2+>Ba2+
B. Ba2+>Ca2+> Mg2+> Al3+
C. Al3+< Mg2+<Ca2+<Ba2+
D. Mg2+>Al3+>Ba2+>Ca2+

8. Which of the following statements explain why caesium has a lower melting point
than sodium?
A. Sodium is a more electropositive metal
B. Sodium has higher ionization energy
C. Sodium has a stronger metallic bond
D. Caesium has a larger atomic radius

9. Transition metals can form complex ions because:
A. they have paired electrons in the d subshell
B. they have unpaired electrons in the d subshell
C. they have empty d orbitals
D. they have small charge/size ratio

10. How many equivalent hybrid orbitals are there in Sp2
-hybridised carbon?
A. four
B. two
C. three
D. one

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