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.
Spring water
River water
Tap water
Sea water
Correct answer is C
Tap water contains less Ca\(^{2+}\) and Mg\(^{2+}\)
Aluminium does not react with either dilute or concentrated trioxonitrate (V) acid because
it is insoluble in either dilute or concentrated trioxonitrate (V) acid
it is lower than hydrogen in the electrochemical series
the reaction with trioxonitrate (V) acid has a light activation energy
an insoluble oxide is formed on its surface which renders it passive
Correct answer is D
Aluminium doesn’t react with either dilute or concentrated trioxonitrate (V) acid because an insoluble oxide is formed on its surface which renders it passive. It will depend on the concentration of the nitric acid used…. Although aluminium reacts with dilute nitric acid to produce aluminium nitrate and hydrogen gas, concentrated (>60%) nitric acid is such a powerful oxidising agent that it instantly causes a thin layer of aluminium oxide to coat the surface of the aluminium
The presence of ammonia gas in a desiccator can exclusively be removed by
phosphorus (V) oxide
fused calcium chloride
calcium oxide
concentrated tetraoxosulphate (VI) acid
Correct answer is D
Ammonia gas can be removed from a dessicator by adding a conc. H2SO4 so as to neutralize it since ammonia gas is basic.
The collision theory explains reaction rates in terms of
size of the product
frequency of collision of the reactants
size of reactant
frequency of collision of the products
Correct answer is B
Collision theory is the theory used to predict the rates of chemical reactions, particularly for gases. The collision theory is based on the assumption that for a reaction to occur it is necessary for the reacting species (atoms or molecules) to come together or collide with one another.
The end products of burning a candle in the atmosphere are water and
carbon (II) oxide
sulphur (IV) oxide
carbon (IV) oxide
sulphur (VI) oxide
Correct answer is C
When we ignite a candle, the hydrocarbon reacts with oxygen (in excess) to produce carbon dioxide and water. The burning sets an air current which gives dome shape to candle flame and it helps to get complete combustion at the bottom and the outer surface of the flame.
CO\(_2\) is produced