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.
In the shown experiment (Fig. 1) the litmus paper will initially
be bleached
turn green
turn red
turn blue
Correct answer is D
\(NH_4Cl → NH_3 + HCl\). rate of diffusion of substances depends too on their molar mass, the smaller the molar mass of a substance the faster the rate of diffusion of that substance. so the litmus paper initially turns blue because ammonia will get to it first since it diffuses faster than HCl.
2.2M
1.1M
0.2M
0.11M
Correct answer is C
No explanation has been provided for this answer.
The periodic classification is an arrangement of the elements
atomic weights
isotopic weights
molecular weights
atomic numbers
Correct answer is D
Elements in the periodic table are arranged according to their atomic number (proton number). Electronegativity increase from left to right while atomic radius increases down the group
Elements in the periodic table are arranged according to their atomic number (proton number). Electronegativity increase from left to right while atomic radius increases down the group
Which of the following statements is correct about the periodic table?
Elements in the same period have the same number of valence electrons
The valence electrons of the elements in the same period increase progressively across the period
Elements in the same group have the same number of electron shells
The non-metallic Properties of the elements tend to decrease across each period
Correct answer is B
The valence electrons refer to the number of electrons in the outer shell. Across a period (horizontal row), the valence electron increases.
I, II, III and IV
I and II only
II only
III and IV only
Correct answer is D
The solubility of a gas decreases with an increase in temperature and a decrease in pressure.