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.
The most suitable substance for putting out petrol fire is
water
carbon(IV) oxide
fire blanket
sand
Correct answer is B
In order to extinguish a petrol fire, you have to cut off the oxygen. This can be done by using carbon dioxide gas to dilute the oxygen available and stop the burning.
\(1.2 \times 10^{22}\)
\(1.2 \times 10^{23}\)
\(2.4 \times 10^{22}\)
\(2.4 \times 10^{23}\)
Correct answer is A
\(1mole = 6.02 \times 10^{23} ions\)
\(0.02moldm^{-3} = 0.02 \times 6.02 \times 10^{23}\)
=\(0.1204 \times 10^{23} = 1.204 \times 10^{22}\)
\(\approxeq 1.2 \times 10^{22}\)
Stainless steel is an alloy comprising of
Fe and C
Fe and Ni
Fe, C and Ni
Fe, C and Al
Correct answer is C
Stainless steel comprises iron (Fe), chromium (Cr), manganese (Mn), silicon (Si), carbon (C) and, in many cases, significant amounts of nickel (Ni) and molybdenum (Mo).
The valence electrons of \(_{12}Mg\) are in the
3s orbital
2p\(_{x}\)
2s orbital
1s orbital
Correct answer is A
\(_{12}Mg = 2, 8, 2\)
\(= 1s^{2} 2s^{2} 2p^{6} 3s^{2}\)
The preferential discharge of ions during electrolysis is influenced by the
mechanism of electrolysis
electrolytic reactions
nature of the electrode
type of electrolytic cell
Correct answer is C
The preferential discharge of ions is influenced by:
- The position of the ions in the electrochemical series
- The concentration of the ions in the electrolyte
- The nature of the electrode