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.
Chromatography is used to separate components of mixture which differ in their rates of ?
diffusion
migration
reaction
sedimentation
Correct answer is B
Chromatography is a method of separating mixtures by using a moving solvent on filter paper. The rate at which each solute moves up the paper depends on how strongly it is absorbed by the paper, and how soluble it is in the solvent.
less than 3.4
greater than 3.4
unaltered
the same as that of the pure water
Correct answer is A
The addition of conc HCL makes the solution more acidic and the solution falls below the original value
Which of the following gases will rekindle a brightly splint?
NO2
NO
N2O
CL2
Correct answer is C
Nitrogen(I)Oxide rekindles a brightly glowing splinter but extinguishes a feebly glowing one which is not hot enough to decompose the gas to liberate oxygen
28
32
44
71
Correct answer is D
500cm3 of the gas weighed 1.58
: 22400cm3 of the gas weight
[22400 X 1.58g] ÷ [ 500 ]
= 71
CaCO3 + 2HCL ⇒ CaCl2 + H2 O + CO2 , is?
1.00 X 1023
6.02 X 1023
6.02 X 1022
6.02 X 1024
Correct answer is C
1 mole of CaCO3 = 100g or 6.02 X 1023
liberated 1 mole of CO2 or 44g or 6.02 X 1023
:100g = 6.02 X 1023
10g of CaCO3 = x
cross multiply
[10g X 6.02 X 1023] / 100g = x
⇒ x = 6.02 X 1022
Since
6.02 X 1023 of CaCO3 liberated 6.02 X 1023 of CO2
⇒ 6.02 X 1022 of CaCO3 will liberate 6.02 X 1022 of CO2