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.
When water was added to a white anhydrous substance X, the colour changed to blue. X is
\(CuSO_{4}\)
\(FeSO_{4}\)
\(Na_{2}SO_{4}\)
\(PbSO_{4}\)
Correct answer is A
When water is added to white coloured anhydrous copper sulphate, its colour changes to blue, indicating that the blue coloured copper sulphate pentahydrate is regenerated.
Potassium Chloride solid does not conduct electricity because
it is a covalent compound
strong cohesive forces make its ions immobile
strong cohesive force makes its molecule immobile
each of potassium and chlorine structures contain noble gas structure
Correct answer is B
For a substance to conduct electricity, it must have charge particles like electrons and ions within it that are able to move freely throughout it. In its solid state, potassium chloride (like many other ionic compounds) have fixed ions, hence, they are immobile and can't conduct electricity.
Halogens generally react with metals to form
alkalis
acids
bases
salts
Correct answer is D
The word "halogen" is a Greek word meaning salt former, because they form salts when they react with metals eg NaCl.
Which of the following statements is NOT a chemical property of an acid?
Evolution of ammonia when heated with ammonium salts
Evolution of carbon dioxide gas when added to a trioxocarbonate (IV) salt
Formation of salt and water with alkalis
Formation of salt and hydrogen gas with reactive metals
Correct answer is A
Ammonium salts react with bases to release ammonia and not with acids.
\(CH\)
\(CH_{2}\)
\(CH_{3}\)
\(CH_{4}\)
Correct answer is B
The percentage of Carbon in the compound is (100 - 14.3)% = 85.7%
C : H
\(\frac{85.7}{12.0} : \frac{14.3}{1.0}\)
\( 7.14 : 14.3\)
\(\frac{7.14}{7.14} : \frac{14.3}{7.14}\)
\(\approxeq 1 : 2\)
Therefore, the empirical formula is \(CH_{2}\).