Learn more about the properties, composition, and structure of substances (elements and compounds) with these Chemistry questions and answers. This Test can be used by students preparing for Chemistry in JAMB, WAEC, NECO or Post UTME.
What number of moles of Cu 2+ will be deposited by 360 coulombs of electricity?
[f = 96500 C mol -1]
5.36 x 10 -4 mole
1. 87 x 10 10 -3 mole
9. 35 x 10 -4 mole
3. 73 x 10 -3
Correct answer is B
Cu\(^{2+}\) + 2e\(^{-}\)\(_{(aq)}\) \(\rightarrow\) Cu\(_{(s)}\)
Liberating 1 mole of Cu
2 x 1F = 2 x 96,500C = 193,000C of electricity is needed
Hence, 193,000C = 1 mole
360C of electricity = \(\frac{360C \times 1 mol}{193,000C}\)
= 0.001865 mol
= 1.87 x 10\(^{-3}\) moles
Na2O2(s) + H2O(1) → NaOH(s) +O2(g)
The substance that is oxidized in the reaction above is
2NaO2(s)
NaOH(aq)
H2O(1)
O2(g)
Correct answer is C
No explanation has been provided for this answer.
The oxidation number of boron in NaBH 4 is
-3
-1
+1
+3
Correct answer is D
No explanation has been provided for this answer.
A major factor considered in selecting a suitable method for preparing a simple salt is its
Crystalline from
melting point
reactivity with dilute acids
solubility in water
Correct answer is D
No explanation has been provided for this answer.
22.40 dm 3
11.20 dm 3
2.24 dm 3
1.12 dm 3
Correct answer is D
No explanation has been provided for this answer.