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 two gases can be used for the demonstration of the fountain experiment?
SO4 and NH3
SO3 and NH3
HCl and NH3
SO2 and CO
Correct answer is C
No explanation has been provided for this answer.
75,000 particles
35,000 particles
25,000 particles
50,000 particles
Correct answer is C
Given:
t12 = 20 years
After the first 20 years, half of the substance (12×100,000=50,000) will have decayed. Hence, we have 100,000 - 50,000 = 50,000 particles left.
After the second 20 years (being 40 years in all), half of the remaining substance (12×50,000=25,000) will have decayed.
Remaining particles after 40 years = 50,000 - 25,000
= 25,000 particles.
Na2CO3 + 2HCl → 2NaCl + H2O + CO2
The indicator most suitable for this reaction should have a pH equal to
5
7
3
9
Correct answer is C
Methyl orange is the best indicator for the reaction with range 3.1 - 4.4.
The molecular shape and bond angle of water are respectively
linear, 180°
bent, 109.5°
tetrahedral, 109.5°
bent, 105°
Correct answer is D
The shape of water molecule = Bent/ V- shaped The bond angle of water = 104.5°/ 105°