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.
Which of the following gases is colourless, odourless and soluble in potassium hydroxide solution?
NO 2
SO 2
NH 3
CO2
Correct answer is D
CO2 (carbon dioxide) is a colorless and odourless gas and very soluble in KOH owning that it is an acidic gas.
8g mol -1
16 gmol -1
32g mol -1
64g mol -1
Correct answer is C
Using the ideal gas equation,
PV = nRT.
where \(n = \frac{mass}{\text{molar mass}}\).
For Hydrogen, \(\frac{m_H}{M_H} = \frac{PV}{RT}\).
For element X, \(\frac{m_X}{M_X} = \frac{PV}{RT}\)
Under the same conditions implies \(\frac{PV}{RT}\) is the same for both hydrogen and X.
\(\frac{m_H}{M_H} = \frac{m_X}{M_X}\)
Molar mass of X = \(\frac{\text{molar mass of hydrogen} \times \text{mass of X}}{\text{mass of hydrogen}}\)
= \(\frac{1 \times 9.6}{0.3}\)
= 32 g/mol
Which of the following increases as boiling water changes to steam?
temperature of the system
degree of disorder in the system
number of molecules
activation energy
Correct answer is B
No explanation has been provided for this answer.
What is the shape of a molecule of CCI4?
Pyramidal
Tetrahedral
Trigonal planar
Linear
Correct answer is B
No explanation has been provided for this answer.
A radioactive solid is best stored
under paraffin oil
under ultraviolet light
in a cool, dark cupboard
in a box lined with lead
Correct answer is D
No explanation has been provided for this answer.