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.
Ca2+
Na+
Zn2+
K+
Correct answer is A
The test indicates the presence of \(Ca_{2+}\).
NaNO3
Zn(NO3)2
Cu(NO3)2
NH4NO3
Correct answer is D
\(NH_4NO_3 → N_2O + 2H_2O\)
oxygen
chlorine
nitrogen
hydrogen
Correct answer is A
The substance used in the steel industry for the removal of carbon, sulphur, and phosphorus impurities from pig iron is oxygen. This process is called "oxidation" and it occurs when oxygen reacts with the impurities in the pig iron, which then form oxides that can be easily removed.
The rate of a reaction usually decreases with a decrease in the concentration of reactants because
kinetic energy decrease
temperature increase
speed increases
reactants collision decrease
Correct answer is D
Decrease in the concentration of reactants reduces the number of molecules that acquire effective collisions, and consequently reduces the reaction rate.
A catalyst speeds up the rate of chemical reaction by
taking part in the reaction
increasing the activation energy of the reaction
lowering the activation energy of the reaction
increasing the heat content
Correct answer is C
Catalyst lowers the activation energy of reaction and hence speeds up the rate of chemical reaction.